Cutis

As many as one-quarter of human cancers are related to chronic inflammation, chronic infection, or both.¹ Extrinsic inflammation leads to generation of proinflammatory cytokines that in turn recruit other inflammatory cells, which is thought to generate a positive amplification loop.² Intrinsic stimuli from proto-oncogenes and mutations in tumor suppressor genes lead to transformed cancer cells that also secrete proinflammatory cytokines, thus propagating the cycle.

Numerous factors have been observed in association with tumor growth, progression, invasion, and metastasis.³ One factor for the development of squamous cell carcinoma (SCC) may be chronic inflammatory dermatoses. To date, reviews of chronic inflammation–associated malignancy have focused on solid organ cancers. We sought to provide an up-to-date review of SCC arising within chronic dermatoses, with an emphasis on the anatomic location of dermatoses involved in the transformation of cancer cells, the lag time from onset of dermatosis to diagnosis of SCC, and the distinctive mechanisms thought to be involved in the tumorigenesis in particular dermatoses.

Discoid Lupus Erythematosus

Discoid lupus erythematosus (DLE) is a chronic cutaneous lupus erythematosus variant with a female to male predominance of 3:1,⁴ and DLE lesions are prone to malignant transformation. Retrospective cohort studies have attempted to characterize who is at risk for SCC and how SCCs behave depending on their location. Cohorts from China,⁵ India,⁶ and Japan⁷ have noted a higher rate of SCC within DLE lesions in men (female to male ratios of 1:2.2, 1:1.6, and 1:2, respectively) and shorter lag times for SCC onset within DLE lesions of the lips (13, 5, and 10 years, respectively) compared to SCC arising in DLE elsewhere (19.2, 11.2, and 26 years, respectively). Studies have noted that DLE lesions of the lips may be prone to more rapid SCC tumorigenesis compared to DLE on cutaneous sites. One study reported SCC in DLE recurrence, metastasis, and death rates of 29%, 16.1%, and 19.4%, respectively,⁵ which exceeds reported rates in non-DLE SCCs (20%, 0.5% to 6%, and 1%, respectively).^5,8

Because SCC arising within DLE is most common on the lips (Figure 1), it has been hypothesized that the high rate of transformation of DLE lesions on the lips may be due to constant exposure to irritation and tobacco, which may accelerate carcinogenesis.⁵ It also has been hypothesized that atrophic discoid lesions have lost sun protection and are more prone to mutagenic UV radiation,⁹ as SCCs arising in DLE lesions virtually always display prominent solar elastosis⁶; however, SCC has been observed to arise in non–sun-exposed DLE lesions in both White and Black patients.¹⁰

Photograph courtesy of Andrea Murina, MD.

Additionally, use of immunosuppressant medications may accelerate the emergence of malignancy or more aggressive forms of malignancy; however, patients with autoimmune disease have a greater risk for malignancy at baseline,¹¹ thus making it difficult to determine the excess risk from medications. There also may be a role for human papillomavirus (HPV) accelerating SCC development in DLE lesions, as demonstrated in a case of SCC arising in DLE lesions of the ears, with viral staining evident within the tumors.¹² However, testing for HPV is not routinely performed in these cases.

Dermatologists need to be aware of the relatively rapid tumorigenesis and aggressive behavior of transformation and aggression seen with SCC arising within orolabial DLE lesions compared to cutaneous lesions, especially those on the lips.

Lichen Planus

Although patients with typical cutaneous lichen planus lesions do not have an increased risk for SCC,¹³ variants of lichen planus may predispose patients to SCC.

Oral Lichen Planus—Oral lichen planus (OLP) lesions are prone to malignant transformation. A systematic review of 16 studies evaluating the risk for OLP-associated SCC revealed an overall transformation rate of 1.09%, with a mean lag time of 4.3 years,¹⁴ compared to a reference rate of 0.2% for oral SCC.¹⁵ A meta-analysis of 19,676 patients with OLP and other oral lichenoid lesions revealed an oral SCC rate of 1.1%, with higher rates of transformation seen in cigarette smokers, alcoholics, and patients with hepatitis C virus infection.¹⁶ The ulcerative subtype of OLP appears to present a greater risk for malignant transformation.¹⁵ Dermatologists also should be cognizant that treatments for OLP such as topical calcineurin inhibitors may support the development of malignancy within inflammatory lesions.¹⁷

Hypertrophic Lichen Planus—The hypertrophic variant of lichen planus (HLP) also is prone to malignant transformation. A 1991 epidemiologic study from Sweden of malignancy arising in lichen planus revealed a disproportionate number of cases arising in verrucous or hypertrophic lesions, with a mean of 12.2 years from onset of the dermatosis to malignancy diagnosis.¹³ A subsequent 2015 retrospective study of 38 patients revealed that SCC had a propensity for the lower limb, favoring the pretibial region and the calf over the foot and the ankle with a reported lag time of 11 years.¹⁸

Although metastatic SCC arising in HLP is rare, 2 cases have been reported. A 24-year-old woman presented with an HLP plaque on the lower leg that developed during childhood and rapidly enlarged 2 months prior to presentation; she eventually died from metastatic disease.¹⁹ In another case, a 34-year-old man presented with an HLP lesion of approximately 10 years’ duration. A well-differentiated SCC was excised, and he developed lymph node metastases 5 months later.²⁰

It is important to note that HLP on the legs often is misdiagnosed as SCC, as pseudoepitheliomatous hyperplasia and squamous metaplasia can be difficult to differentiate clinically and histologically.^21,22 In the case of multiple eruptive SCCs of the lower leg, clinical correlation is essential to avoid unnecessary and ineffective surgical treatment.

Patients with HLP may exhibit Wickham striae, follicular accentuation, and mucocutaneous lichen planus at other sites, or a correlative initiation of possible culprit medications.²³ Because true SCC arising within HLP is relatively rare, its malignant potential is not as clear as those arising within DLE; however, the lower limb appears to be the most common location for SCC within HLP.Nail Lichen Planus—Squamous cell carcinoma arising in nail lichen planus is rare. A report of 2 patients were diagnosed with lichen planus approximately 15 years prior to diagnosis of ungual SCC.²⁴ Given the rarity of this presentation, it is difficult to ascertain the approximate lag time and other risk factors. Furthermore, the role of HPV in these cases was not ruled out. Oncogenic HPV strains have been reported in patients with periungual SCC.^25,26

Lichen Sclerosus

Lichen sclerosus (LS) is a chronic inflammatory dermatosis that favors the anogenital area in a female to male ratio of 10:1.²⁷ It is considered a premalignant condition for SCC tumorigenesis and may be a strong predictor of vulvar SCC (Figure 2), as 62% of vulvar SCC cases (N=78) may have adjacent LS.²⁸

Photograph courtesy of Laura C. Williams, MD (New Orleans, Louisiana).

In a Dutch cohort of 3038 women with LS, 2.6% of patients developed vulvar SCC at a median of 3.3 years after LS diagnosis.²⁹ Other studies have estimated a lag time of 4 years until SCC presentation.³⁰ An Italian cohort of 976 women similarly observed that 2.7% of patients developed premalignancy or SCC.³¹ It was previously estimated that 3% to 5% of patients with LS developed SCC; however, prior studies may have included cases of vulvar intraepithelial neoplasia with low risk for invasive SCC, which might have overestimated true risk of SCC.³² Another confounding factor for elucidating SCC on a background of LS may be the presence of HPV.³³ Extragenital LS does not appear to have similar potential for malignant transformation.³⁴

In a prospective Australian cohort of 507 women with LS (mean age, 55.4 years), remission was induced with potent topical corticosteroids.³⁵ Patients who were adherent to a topical regimen did not develop SCC during follow-up. Those who were nonadherent or partially adherent had a 4.7% risk for SCC.³⁵ In a similar prospective study of 83 women in France, the SCC rate was 9.6% in lesions that were untreated or irregularly treated.³⁶ These studies provide essential evidence that appropriately treating LS can prevent SCC at a later date, though longer-term data are lacking.

The rate of SCC arising in male genital LS may approach 8.4%,³⁷ with a lag time of 17 years from onset of LS to SCC diagnosis.³⁸ Although circumcision often is considered curative for male genital LS, patients have been observed to develop penile SCC at least 5 years after circumcision.³⁹ Male penile SCC in a background of LS may not necessarily be HPV associated.⁴⁰

Marjolin Ulcer

Chronic ulcers or scars, typically postburn scars, may undergo malignant transformation, with SCC being the most common carcinoma.⁴¹ Squamous cell carcinoma in the context of a chronic ulcer or wound is known as a Marjolin ulcer (MU). Up to 2% of burn scars have been observed to undergo malignant transformation.⁴² Marjolin ulcers tend to behave aggressively once they form, and it has been proposed that removal of scar tissue may be a preventive therapeutic strategy.⁴³ Cohort studies of MU on the lower extremities have observed lag times of 26.4⁴⁴ and 37.9⁴⁵ years, with both studies also noting relatively high rates of local recurrence.

The pathogenesis of MU appears to be multifactorial. Chronic inflammation and scar formation have been implicated. Chronic inflammation and irritation of lesions at natural creases are thought to increase mitotic activity,⁴¹ and local accumulation of toxin may promote mutagenesis.⁴⁶ Scar formation may create a locally immunoprivileged site, allowing for developing tumors to evade the immune system⁴⁷ and become even more aggressive as the tumor accumulates.⁴⁸ Scar formation also may prevent the ability of immune cells to penetrate the tumor microenvironment and access lymphatic channels.⁴⁹

Hidradenitis Suppurativa

As many as 3.2% of patients with chronic hidradenitis suppurativa (HS) experience malignant transformation to SCC.⁵⁰ Early HS displays subclinical lymphedema in affected sites, which can progress to chronic fibrosis, stasis, and accumulation of protein-rich fluid.⁵¹ Stasis changes have been associated with altered local inflammatory proteins, such as toll-like receptors, β-defensins, and interleukins.⁵²

A retrospective cohort study of 12 patients revealed a lag time of 28.5 years from HS diagnosis to the manifestation of malignancy.⁵³ After local excision, 7 patients developed recurrence, with 100% mortality. Squamous cell carcinomas were well differentiated and moderately differentiated.⁵³ A 2017 literature review of 62 case reports calculated a mean lag time of 27 years. Despite 85% of SCCs being well differentiated and moderately differentiated, nearly half of patients died within 2 years.⁵⁴ As seen in other inflammatory conditions, HPV can complicate perineal HS and promote SCC tumorigenesis.⁵⁵

Squamous cell carcinomas arising within HS lesions are more prevalent in males (6.75:1 ratio),^54,56 despite HS being more prevalent in females (2:1 ratio).⁵⁷ Similar to DLE, SCCs arising in HS are aggressive and are seen more in males, despite both conditions being female predominant. Incidence and mortality rates for primary cutaneous SCC are higher for men vs women⁵⁸; however, the discordance in aggressive behavior seen more commonly in SCC arising from HS or DLE in male patients has yet to be explained.

 

 

Necrobiosis Lipoidica Diabeticorum

Malignancy arising within necrobiosis lipoidica diabeticorum (NLD) is rare. A review of 14 published cases noted that 13 were SCC and 1 was leiomyosarcoma.⁵⁹ The lag time was 21.5 years; 31% of cases (N=14) presented with regional lymph node metastasis. Although chronic ulceration is a risk factor for SCC and occurs in as many as one-third of NLD cases, its correlation with ulceration and malignant transformation has not been characterized.

Epidermolysis Bullosa

Recessive dystrophic epidermolysis bullosa (RDEB) is a noninflammatory inherited blistering disease, and patients have an inherently high risk for aggressive SCC.⁶⁰ Other forms of epidermolysis bullosa can lead to SCC, but the rarer RDEB accounts for 69% of SCC cases, with a median age of 36 years at presentation.⁶¹ Although SCCs tend to be well differentiated in RDEB (73.9%),⁶¹ they also exhibit highly aggressive behavior.⁶² In the most severe variant—RDEB-generalized severe—the cumulative risk for SCC-related death in an Australian population was 84.4% at 34 years of age.⁶³

As RDEB is an inherited disorder with potential for malignancy at a young age, the pathogenesis is plausibly different from the previously discussed inflammatory dermatoses. This disease is characterized by a mutation in the collagen VII gene, leading to loss of anchoring fibrils and a basement membrane zone split.⁶⁴ There also can be inherent fibroblast alterations; RDEB fibroblasts create an environment for tumor growth by supporting malignant-cell adhesion and invasion.⁶⁵ Mutations in p53,⁶⁶ local alterations in transforming growth factor β activity,⁶⁷ and downstream matrix metalloproteinase activity⁶⁸ have been implicated.

Additionally, keratinocytes may retain the N-terminal noncollagenous (NC1) domain of truncated collagen VII while losing the anchoring NC2 domain in mutated collagen VII RDEB, thereby supporting anchorless keratinocyte survival and higher metastatic potential.⁶⁹ Retention of this truncated NC1 domain has shown conversion of RDEB keratinocytes to tumor in a xenotransplant mouse model.⁷⁰ A high level of type VII collagen itself may inherently be protumorigenic for keratinocytes.⁷¹

There does not appear to be evidence for HPV involvement in RDEB-associated SCC.⁷² Squamous cell carcinoma development in RDEB appears to be multifactorial,⁷³ but validated tumor models are lacking. Other than conventional oncologic therapy, future directions in the management of RDEB may include gene-, protein- and cell-targeted therapies.⁷³

Conclusion

Squamous cell carcinomas are known to arise within chronic cutaneous inflammatory dermatoses. Tumorigenesis peaks relatively early in new orolabial DLE, LS, and OLP cases, and can occur over many decades in cutaneous DLE, HLP, HS, NLD, and chronic wounds or scars, summarized in the Table. Frequent SCCs are observed in high-risk subtypes of epidermolysis bullosa. Dermatologists must examine areas affected by these diseases at regular intervals, being mindful of the possibility of SCC development. Furthermore, dermatologists should adopt a lower threshold to biopsy suspicious lesions, especially those that develop within relatively new orolabial DLE, chronic HS, or chronic wound cases, as SCC in these settings is particularly aggressive and displays mortality and metastasis rates that exceed those of common cutaneous SCC.


As many as one-quarter of human cancers are related to chronic inflammation, chronic infection, or both.¹ Extrinsic inflammation leads to generation of proinflammatory cytokines that in turn recruit other inflammatory cells, which is thought to generate a positive amplification loop.² Intrinsic stimuli from proto-oncogenes and mutations in tumor suppressor genes lead to transformed cancer cells that also secrete proinflammatory cytokines, thus propagating the cycle.

Numerous factors have been observed in association with tumor growth, progression, invasion, and metastasis.³ One factor for the development of squamous cell carcinoma (SCC) may be chronic inflammatory dermatoses. To date, reviews of chronic inflammation–associated malignancy have focused on solid organ cancers. We sought to provide an up-to-date review of SCC arising within chronic dermatoses, with an emphasis on the anatomic location of dermatoses involved in the transformation of cancer cells, the lag time from onset of dermatosis to diagnosis of SCC, and the distinctive mechanisms thought to be involved in the tumorigenesis in particular dermatoses.

Discoid Lupus Erythematosus

Discoid lupus erythematosus (DLE) is a chronic cutaneous lupus erythematosus variant with a female to male predominance of 3:1,⁴ and DLE lesions are prone to malignant transformation. Retrospective cohort studies have attempted to characterize who is at risk for SCC and how SCCs behave depending on their location. Cohorts from China,⁵ India,⁶ and Japan⁷ have noted a higher rate of SCC within DLE lesions in men (female to male ratios of 1:2.2, 1:1.6, and 1:2, respectively) and shorter lag times for SCC onset within DLE lesions of the lips (13, 5, and 10 years, respectively) compared to SCC arising in DLE elsewhere (19.2, 11.2, and 26 years, respectively). Studies have noted that DLE lesions of the lips may be prone to more rapid SCC tumorigenesis compared to DLE on cutaneous sites. One study reported SCC in DLE recurrence, metastasis, and death rates of 29%, 16.1%, and 19.4%, respectively,⁵ which exceeds reported rates in non-DLE SCCs (20%, 0.5% to 6%, and 1%, respectively).^5,8

Because SCC arising within DLE is most common on the lips (Figure 1), it has been hypothesized that the high rate of transformation of DLE lesions on the lips may be due to constant exposure to irritation and tobacco, which may accelerate carcinogenesis.⁵ It also has been hypothesized that atrophic discoid lesions have lost sun protection and are more prone to mutagenic UV radiation,⁹ as SCCs arising in DLE lesions virtually always display prominent solar elastosis⁶; however, SCC has been observed to arise in non–sun-exposed DLE lesions in both White and Black patients.¹⁰

Photograph courtesy of Andrea Murina, MD.

Additionally, use of immunosuppressant medications may accelerate the emergence of malignancy or more aggressive forms of malignancy; however, patients with autoimmune disease have a greater risk for malignancy at baseline,¹¹ thus making it difficult to determine the excess risk from medications. There also may be a role for human papillomavirus (HPV) accelerating SCC development in DLE lesions, as demonstrated in a case of SCC arising in DLE lesions of the ears, with viral staining evident within the tumors.¹² However, testing for HPV is not routinely performed in these cases.

Dermatologists need to be aware of the relatively rapid tumorigenesis and aggressive behavior of transformation and aggression seen with SCC arising within orolabial DLE lesions compared to cutaneous lesions, especially those on the lips.

Lichen Planus

Although patients with typical cutaneous lichen planus lesions do not have an increased risk for SCC,¹³ variants of lichen planus may predispose patients to SCC.

Oral Lichen Planus—Oral lichen planus (OLP) lesions are prone to malignant transformation. A systematic review of 16 studies evaluating the risk for OLP-associated SCC revealed an overall transformation rate of 1.09%, with a mean lag time of 4.3 years,¹⁴ compared to a reference rate of 0.2% for oral SCC.¹⁵ A meta-analysis of 19,676 patients with OLP and other oral lichenoid lesions revealed an oral SCC rate of 1.1%, with higher rates of transformation seen in cigarette smokers, alcoholics, and patients with hepatitis C virus infection.¹⁶ The ulcerative subtype of OLP appears to present a greater risk for malignant transformation.¹⁵ Dermatologists also should be cognizant that treatments for OLP such as topical calcineurin inhibitors may support the development of malignancy within inflammatory lesions.¹⁷

Hypertrophic Lichen Planus—The hypertrophic variant of lichen planus (HLP) also is prone to malignant transformation. A 1991 epidemiologic study from Sweden of malignancy arising in lichen planus revealed a disproportionate number of cases arising in verrucous or hypertrophic lesions, with a mean of 12.2 years from onset of the dermatosis to malignancy diagnosis.¹³ A subsequent 2015 retrospective study of 38 patients revealed that SCC had a propensity for the lower limb, favoring the pretibial region and the calf over the foot and the ankle with a reported lag time of 11 years.¹⁸

Although metastatic SCC arising in HLP is rare, 2 cases have been reported. A 24-year-old woman presented with an HLP plaque on the lower leg that developed during childhood and rapidly enlarged 2 months prior to presentation; she eventually died from metastatic disease.¹⁹ In another case, a 34-year-old man presented with an HLP lesion of approximately 10 years’ duration. A well-differentiated SCC was excised, and he developed lymph node metastases 5 months later.²⁰

It is important to note that HLP on the legs often is misdiagnosed as SCC, as pseudoepitheliomatous hyperplasia and squamous metaplasia can be difficult to differentiate clinically and histologically.^21,22 In the case of multiple eruptive SCCs of the lower leg, clinical correlation is essential to avoid unnecessary and ineffective surgical treatment.

Patients with HLP may exhibit Wickham striae, follicular accentuation, and mucocutaneous lichen planus at other sites, or a correlative initiation of possible culprit medications.²³ Because true SCC arising within HLP is relatively rare, its malignant potential is not as clear as those arising within DLE; however, the lower limb appears to be the most common location for SCC within HLP.Nail Lichen Planus—Squamous cell carcinoma arising in nail lichen planus is rare. A report of 2 patients were diagnosed with lichen planus approximately 15 years prior to diagnosis of ungual SCC.²⁴ Given the rarity of this presentation, it is difficult to ascertain the approximate lag time and other risk factors. Furthermore, the role of HPV in these cases was not ruled out. Oncogenic HPV strains have been reported in patients with periungual SCC.^25,26

Lichen Sclerosus

Lichen sclerosus (LS) is a chronic inflammatory dermatosis that favors the anogenital area in a female to male ratio of 10:1.²⁷ It is considered a premalignant condition for SCC tumorigenesis and may be a strong predictor of vulvar SCC (Figure 2), as 62% of vulvar SCC cases (N=78) may have adjacent LS.²⁸

Photograph courtesy of Laura C. Williams, MD (New Orleans, Louisiana).

In a Dutch cohort of 3038 women with LS, 2.6% of patients developed vulvar SCC at a median of 3.3 years after LS diagnosis.²⁹ Other studies have estimated a lag time of 4 years until SCC presentation.³⁰ An Italian cohort of 976 women similarly observed that 2.7% of patients developed premalignancy or SCC.³¹ It was previously estimated that 3% to 5% of patients with LS developed SCC; however, prior studies may have included cases of vulvar intraepithelial neoplasia with low risk for invasive SCC, which might have overestimated true risk of SCC.³² Another confounding factor for elucidating SCC on a background of LS may be the presence of HPV.³³ Extragenital LS does not appear to have similar potential for malignant transformation.³⁴

In a prospective Australian cohort of 507 women with LS (mean age, 55.4 years), remission was induced with potent topical corticosteroids.³⁵ Patients who were adherent to a topical regimen did not develop SCC during follow-up. Those who were nonadherent or partially adherent had a 4.7% risk for SCC.³⁵ In a similar prospective study of 83 women in France, the SCC rate was 9.6% in lesions that were untreated or irregularly treated.³⁶ These studies provide essential evidence that appropriately treating LS can prevent SCC at a later date, though longer-term data are lacking.

The rate of SCC arising in male genital LS may approach 8.4%,³⁷ with a lag time of 17 years from onset of LS to SCC diagnosis.³⁸ Although circumcision often is considered curative for male genital LS, patients have been observed to develop penile SCC at least 5 years after circumcision.³⁹ Male penile SCC in a background of LS may not necessarily be HPV associated.⁴⁰

Marjolin Ulcer

Chronic ulcers or scars, typically postburn scars, may undergo malignant transformation, with SCC being the most common carcinoma.⁴¹ Squamous cell carcinoma in the context of a chronic ulcer or wound is known as a Marjolin ulcer (MU). Up to 2% of burn scars have been observed to undergo malignant transformation.⁴² Marjolin ulcers tend to behave aggressively once they form, and it has been proposed that removal of scar tissue may be a preventive therapeutic strategy.⁴³ Cohort studies of MU on the lower extremities have observed lag times of 26.4⁴⁴ and 37.9⁴⁵ years, with both studies also noting relatively high rates of local recurrence.

The pathogenesis of MU appears to be multifactorial. Chronic inflammation and scar formation have been implicated. Chronic inflammation and irritation of lesions at natural creases are thought to increase mitotic activity,⁴¹ and local accumulation of toxin may promote mutagenesis.⁴⁶ Scar formation may create a locally immunoprivileged site, allowing for developing tumors to evade the immune system⁴⁷ and become even more aggressive as the tumor accumulates.⁴⁸ Scar formation also may prevent the ability of immune cells to penetrate the tumor microenvironment and access lymphatic channels.⁴⁹

Hidradenitis Suppurativa

As many as 3.2% of patients with chronic hidradenitis suppurativa (HS) experience malignant transformation to SCC.⁵⁰ Early HS displays subclinical lymphedema in affected sites, which can progress to chronic fibrosis, stasis, and accumulation of protein-rich fluid.⁵¹ Stasis changes have been associated with altered local inflammatory proteins, such as toll-like receptors, β-defensins, and interleukins.⁵²

A retrospective cohort study of 12 patients revealed a lag time of 28.5 years from HS diagnosis to the manifestation of malignancy.⁵³ After local excision, 7 patients developed recurrence, with 100% mortality. Squamous cell carcinomas were well differentiated and moderately differentiated.⁵³ A 2017 literature review of 62 case reports calculated a mean lag time of 27 years. Despite 85% of SCCs being well differentiated and moderately differentiated, nearly half of patients died within 2 years.⁵⁴ As seen in other inflammatory conditions, HPV can complicate perineal HS and promote SCC tumorigenesis.⁵⁵

Squamous cell carcinomas arising within HS lesions are more prevalent in males (6.75:1 ratio),^54,56 despite HS being more prevalent in females (2:1 ratio).⁵⁷ Similar to DLE, SCCs arising in HS are aggressive and are seen more in males, despite both conditions being female predominant. Incidence and mortality rates for primary cutaneous SCC are higher for men vs women⁵⁸; however, the discordance in aggressive behavior seen more commonly in SCC arising from HS or DLE in male patients has yet to be explained.

 

 

Necrobiosis Lipoidica Diabeticorum

Malignancy arising within necrobiosis lipoidica diabeticorum (NLD) is rare. A review of 14 published cases noted that 13 were SCC and 1 was leiomyosarcoma.⁵⁹ The lag time was 21.5 years; 31% of cases (N=14) presented with regional lymph node metastasis. Although chronic ulceration is a risk factor for SCC and occurs in as many as one-third of NLD cases, its correlation with ulceration and malignant transformation has not been characterized.

Epidermolysis Bullosa

Recessive dystrophic epidermolysis bullosa (RDEB) is a noninflammatory inherited blistering disease, and patients have an inherently high risk for aggressive SCC.⁶⁰ Other forms of epidermolysis bullosa can lead to SCC, but the rarer RDEB accounts for 69% of SCC cases, with a median age of 36 years at presentation.⁶¹ Although SCCs tend to be well differentiated in RDEB (73.9%),⁶¹ they also exhibit highly aggressive behavior.⁶² In the most severe variant—RDEB-generalized severe—the cumulative risk for SCC-related death in an Australian population was 84.4% at 34 years of age.⁶³

As RDEB is an inherited disorder with potential for malignancy at a young age, the pathogenesis is plausibly different from the previously discussed inflammatory dermatoses. This disease is characterized by a mutation in the collagen VII gene, leading to loss of anchoring fibrils and a basement membrane zone split.⁶⁴ There also can be inherent fibroblast alterations; RDEB fibroblasts create an environment for tumor growth by supporting malignant-cell adhesion and invasion.⁶⁵ Mutations in p53,⁶⁶ local alterations in transforming growth factor β activity,⁶⁷ and downstream matrix metalloproteinase activity⁶⁸ have been implicated.

Additionally, keratinocytes may retain the N-terminal noncollagenous (NC1) domain of truncated collagen VII while losing the anchoring NC2 domain in mutated collagen VII RDEB, thereby supporting anchorless keratinocyte survival and higher metastatic potential.⁶⁹ Retention of this truncated NC1 domain has shown conversion of RDEB keratinocytes to tumor in a xenotransplant mouse model.⁷⁰ A high level of type VII collagen itself may inherently be protumorigenic for keratinocytes.⁷¹

There does not appear to be evidence for HPV involvement in RDEB-associated SCC.⁷² Squamous cell carcinoma development in RDEB appears to be multifactorial,⁷³ but validated tumor models are lacking. Other than conventional oncologic therapy, future directions in the management of RDEB may include gene-, protein- and cell-targeted therapies.⁷³

Conclusion

Squamous cell carcinomas are known to arise within chronic cutaneous inflammatory dermatoses. Tumorigenesis peaks relatively early in new orolabial DLE, LS, and OLP cases, and can occur over many decades in cutaneous DLE, HLP, HS, NLD, and chronic wounds or scars, summarized in the Table. Frequent SCCs are observed in high-risk subtypes of epidermolysis bullosa. Dermatologists must examine areas affected by these diseases at regular intervals, being mindful of the possibility of SCC development. Furthermore, dermatologists should adopt a lower threshold to biopsy suspicious lesions, especially those that develop within relatively new orolabial DLE, chronic HS, or chronic wound cases, as SCC in these settings is particularly aggressive and displays mortality and metastasis rates that exceed those of common cutaneous SCC.


As many as one-quarter of human cancers are related to chronic inflammation, chronic infection, or both.¹ Extrinsic inflammation leads to generation of proinflammatory cytokines that in turn recruit other inflammatory cells, which is thought to generate a positive amplification loop.² Intrinsic stimuli from proto-oncogenes and mutations in tumor suppressor genes lead to transformed cancer cells that also secrete proinflammatory cytokines, thus propagating the cycle.

Numerous factors have been observed in association with tumor growth, progression, invasion, and metastasis.³ One factor for the development of squamous cell carcinoma (SCC) may be chronic inflammatory dermatoses. To date, reviews of chronic inflammation–associated malignancy have focused on solid organ cancers. We sought to provide an up-to-date review of SCC arising within chronic dermatoses, with an emphasis on the anatomic location of dermatoses involved in the transformation of cancer cells, the lag time from onset of dermatosis to diagnosis of SCC, and the distinctive mechanisms thought to be involved in the tumorigenesis in particular dermatoses.

Discoid Lupus Erythematosus

Discoid lupus erythematosus (DLE) is a chronic cutaneous lupus erythematosus variant with a female to male predominance of 3:1,⁴ and DLE lesions are prone to malignant transformation. Retrospective cohort studies have attempted to characterize who is at risk for SCC and how SCCs behave depending on their location. Cohorts from China,⁵ India,⁶ and Japan⁷ have noted a higher rate of SCC within DLE lesions in men (female to male ratios of 1:2.2, 1:1.6, and 1:2, respectively) and shorter lag times for SCC onset within DLE lesions of the lips (13, 5, and 10 years, respectively) compared to SCC arising in DLE elsewhere (19.2, 11.2, and 26 years, respectively). Studies have noted that DLE lesions of the lips may be prone to more rapid SCC tumorigenesis compared to DLE on cutaneous sites. One study reported SCC in DLE recurrence, metastasis, and death rates of 29%, 16.1%, and 19.4%, respectively,⁵ which exceeds reported rates in non-DLE SCCs (20%, 0.5% to 6%, and 1%, respectively).^5,8

Because SCC arising within DLE is most common on the lips (Figure 1), it has been hypothesized that the high rate of transformation of DLE lesions on the lips may be due to constant exposure to irritation and tobacco, which may accelerate carcinogenesis.⁵ It also has been hypothesized that atrophic discoid lesions have lost sun protection and are more prone to mutagenic UV radiation,⁹ as SCCs arising in DLE lesions virtually always display prominent solar elastosis⁶; however, SCC has been observed to arise in non–sun-exposed DLE lesions in both White and Black patients.¹⁰

Photograph courtesy of Andrea Murina, MD.

Additionally, use of immunosuppressant medications may accelerate the emergence of malignancy or more aggressive forms of malignancy; however, patients with autoimmune disease have a greater risk for malignancy at baseline,¹¹ thus making it difficult to determine the excess risk from medications. There also may be a role for human papillomavirus (HPV) accelerating SCC development in DLE lesions, as demonstrated in a case of SCC arising in DLE lesions of the ears, with viral staining evident within the tumors.¹² However, testing for HPV is not routinely performed in these cases.

Dermatologists need to be aware of the relatively rapid tumorigenesis and aggressive behavior of transformation and aggression seen with SCC arising within orolabial DLE lesions compared to cutaneous lesions, especially those on the lips.

Lichen Planus

Although patients with typical cutaneous lichen planus lesions do not have an increased risk for SCC,¹³ variants of lichen planus may predispose patients to SCC.

Oral Lichen Planus—Oral lichen planus (OLP) lesions are prone to malignant transformation. A systematic review of 16 studies evaluating the risk for OLP-associated SCC revealed an overall transformation rate of 1.09%, with a mean lag time of 4.3 years,¹⁴ compared to a reference rate of 0.2% for oral SCC.¹⁵ A meta-analysis of 19,676 patients with OLP and other oral lichenoid lesions revealed an oral SCC rate of 1.1%, with higher rates of transformation seen in cigarette smokers, alcoholics, and patients with hepatitis C virus infection.¹⁶ The ulcerative subtype of OLP appears to present a greater risk for malignant transformation.¹⁵ Dermatologists also should be cognizant that treatments for OLP such as topical calcineurin inhibitors may support the development of malignancy within inflammatory lesions.¹⁷

Hypertrophic Lichen Planus—The hypertrophic variant of lichen planus (HLP) also is prone to malignant transformation. A 1991 epidemiologic study from Sweden of malignancy arising in lichen planus revealed a disproportionate number of cases arising in verrucous or hypertrophic lesions, with a mean of 12.2 years from onset of the dermatosis to malignancy diagnosis.¹³ A subsequent 2015 retrospective study of 38 patients revealed that SCC had a propensity for the lower limb, favoring the pretibial region and the calf over the foot and the ankle with a reported lag time of 11 years.¹⁸

Although metastatic SCC arising in HLP is rare, 2 cases have been reported. A 24-year-old woman presented with an HLP plaque on the lower leg that developed during childhood and rapidly enlarged 2 months prior to presentation; she eventually died from metastatic disease.¹⁹ In another case, a 34-year-old man presented with an HLP lesion of approximately 10 years’ duration. A well-differentiated SCC was excised, and he developed lymph node metastases 5 months later.²⁰

It is important to note that HLP on the legs often is misdiagnosed as SCC, as pseudoepitheliomatous hyperplasia and squamous metaplasia can be difficult to differentiate clinically and histologically.^21,22 In the case of multiple eruptive SCCs of the lower leg, clinical correlation is essential to avoid unnecessary and ineffective surgical treatment.

Patients with HLP may exhibit Wickham striae, follicular accentuation, and mucocutaneous lichen planus at other sites, or a correlative initiation of possible culprit medications.²³ Because true SCC arising within HLP is relatively rare, its malignant potential is not as clear as those arising within DLE; however, the lower limb appears to be the most common location for SCC within HLP.Nail Lichen Planus—Squamous cell carcinoma arising in nail lichen planus is rare. A report of 2 patients were diagnosed with lichen planus approximately 15 years prior to diagnosis of ungual SCC.²⁴ Given the rarity of this presentation, it is difficult to ascertain the approximate lag time and other risk factors. Furthermore, the role of HPV in these cases was not ruled out. Oncogenic HPV strains have been reported in patients with periungual SCC.^25,26

Lichen Sclerosus

Lichen sclerosus (LS) is a chronic inflammatory dermatosis that favors the anogenital area in a female to male ratio of 10:1.²⁷ It is considered a premalignant condition for SCC tumorigenesis and may be a strong predictor of vulvar SCC (Figure 2), as 62% of vulvar SCC cases (N=78) may have adjacent LS.²⁸

Photograph courtesy of Laura C. Williams, MD (New Orleans, Louisiana).

In a Dutch cohort of 3038 women with LS, 2.6% of patients developed vulvar SCC at a median of 3.3 years after LS diagnosis.²⁹ Other studies have estimated a lag time of 4 years until SCC presentation.³⁰ An Italian cohort of 976 women similarly observed that 2.7% of patients developed premalignancy or SCC.³¹ It was previously estimated that 3% to 5% of patients with LS developed SCC; however, prior studies may have included cases of vulvar intraepithelial neoplasia with low risk for invasive SCC, which might have overestimated true risk of SCC.³² Another confounding factor for elucidating SCC on a background of LS may be the presence of HPV.³³ Extragenital LS does not appear to have similar potential for malignant transformation.³⁴

In a prospective Australian cohort of 507 women with LS (mean age, 55.4 years), remission was induced with potent topical corticosteroids.³⁵ Patients who were adherent to a topical regimen did not develop SCC during follow-up. Those who were nonadherent or partially adherent had a 4.7% risk for SCC.³⁵ In a similar prospective study of 83 women in France, the SCC rate was 9.6% in lesions that were untreated or irregularly treated.³⁶ These studies provide essential evidence that appropriately treating LS can prevent SCC at a later date, though longer-term data are lacking.

The rate of SCC arising in male genital LS may approach 8.4%,³⁷ with a lag time of 17 years from onset of LS to SCC diagnosis.³⁸ Although circumcision often is considered curative for male genital LS, patients have been observed to develop penile SCC at least 5 years after circumcision.³⁹ Male penile SCC in a background of LS may not necessarily be HPV associated.⁴⁰

Marjolin Ulcer

Chronic ulcers or scars, typically postburn scars, may undergo malignant transformation, with SCC being the most common carcinoma.⁴¹ Squamous cell carcinoma in the context of a chronic ulcer or wound is known as a Marjolin ulcer (MU). Up to 2% of burn scars have been observed to undergo malignant transformation.⁴² Marjolin ulcers tend to behave aggressively once they form, and it has been proposed that removal of scar tissue may be a preventive therapeutic strategy.⁴³ Cohort studies of MU on the lower extremities have observed lag times of 26.4⁴⁴ and 37.9⁴⁵ years, with both studies also noting relatively high rates of local recurrence.

The pathogenesis of MU appears to be multifactorial. Chronic inflammation and scar formation have been implicated. Chronic inflammation and irritation of lesions at natural creases are thought to increase mitotic activity,⁴¹ and local accumulation of toxin may promote mutagenesis.⁴⁶ Scar formation may create a locally immunoprivileged site, allowing for developing tumors to evade the immune system⁴⁷ and become even more aggressive as the tumor accumulates.⁴⁸ Scar formation also may prevent the ability of immune cells to penetrate the tumor microenvironment and access lymphatic channels.⁴⁹

Hidradenitis Suppurativa

As many as 3.2% of patients with chronic hidradenitis suppurativa (HS) experience malignant transformation to SCC.⁵⁰ Early HS displays subclinical lymphedema in affected sites, which can progress to chronic fibrosis, stasis, and accumulation of protein-rich fluid.⁵¹ Stasis changes have been associated with altered local inflammatory proteins, such as toll-like receptors, β-defensins, and interleukins.⁵²

A retrospective cohort study of 12 patients revealed a lag time of 28.5 years from HS diagnosis to the manifestation of malignancy.⁵³ After local excision, 7 patients developed recurrence, with 100% mortality. Squamous cell carcinomas were well differentiated and moderately differentiated.⁵³ A 2017 literature review of 62 case reports calculated a mean lag time of 27 years. Despite 85% of SCCs being well differentiated and moderately differentiated, nearly half of patients died within 2 years.⁵⁴ As seen in other inflammatory conditions, HPV can complicate perineal HS and promote SCC tumorigenesis.⁵⁵

Squamous cell carcinomas arising within HS lesions are more prevalent in males (6.75:1 ratio),^54,56 despite HS being more prevalent in females (2:1 ratio).⁵⁷ Similar to DLE, SCCs arising in HS are aggressive and are seen more in males, despite both conditions being female predominant. Incidence and mortality rates for primary cutaneous SCC are higher for men vs women⁵⁸; however, the discordance in aggressive behavior seen more commonly in SCC arising from HS or DLE in male patients has yet to be explained.

 

 

Necrobiosis Lipoidica Diabeticorum

Malignancy arising within necrobiosis lipoidica diabeticorum (NLD) is rare. A review of 14 published cases noted that 13 were SCC and 1 was leiomyosarcoma.⁵⁹ The lag time was 21.5 years; 31% of cases (N=14) presented with regional lymph node metastasis. Although chronic ulceration is a risk factor for SCC and occurs in as many as one-third of NLD cases, its correlation with ulceration and malignant transformation has not been characterized.

Epidermolysis Bullosa

Recessive dystrophic epidermolysis bullosa (RDEB) is a noninflammatory inherited blistering disease, and patients have an inherently high risk for aggressive SCC.⁶⁰ Other forms of epidermolysis bullosa can lead to SCC, but the rarer RDEB accounts for 69% of SCC cases, with a median age of 36 years at presentation.⁶¹ Although SCCs tend to be well differentiated in RDEB (73.9%),⁶¹ they also exhibit highly aggressive behavior.⁶² In the most severe variant—RDEB-generalized severe—the cumulative risk for SCC-related death in an Australian population was 84.4% at 34 years of age.⁶³

As RDEB is an inherited disorder with potential for malignancy at a young age, the pathogenesis is plausibly different from the previously discussed inflammatory dermatoses. This disease is characterized by a mutation in the collagen VII gene, leading to loss of anchoring fibrils and a basement membrane zone split.⁶⁴ There also can be inherent fibroblast alterations; RDEB fibroblasts create an environment for tumor growth by supporting malignant-cell adhesion and invasion.⁶⁵ Mutations in p53,⁶⁶ local alterations in transforming growth factor β activity,⁶⁷ and downstream matrix metalloproteinase activity⁶⁸ have been implicated.

Additionally, keratinocytes may retain the N-terminal noncollagenous (NC1) domain of truncated collagen VII while losing the anchoring NC2 domain in mutated collagen VII RDEB, thereby supporting anchorless keratinocyte survival and higher metastatic potential.⁶⁹ Retention of this truncated NC1 domain has shown conversion of RDEB keratinocytes to tumor in a xenotransplant mouse model.⁷⁰ A high level of type VII collagen itself may inherently be protumorigenic for keratinocytes.⁷¹

There does not appear to be evidence for HPV involvement in RDEB-associated SCC.⁷² Squamous cell carcinoma development in RDEB appears to be multifactorial,⁷³ but validated tumor models are lacking. Other than conventional oncologic therapy, future directions in the management of RDEB may include gene-, protein- and cell-targeted therapies.⁷³

Conclusion

Squamous cell carcinomas are known to arise within chronic cutaneous inflammatory dermatoses. Tumorigenesis peaks relatively early in new orolabial DLE, LS, and OLP cases, and can occur over many decades in cutaneous DLE, HLP, HS, NLD, and chronic wounds or scars, summarized in the Table. Frequent SCCs are observed in high-risk subtypes of epidermolysis bullosa. Dermatologists must examine areas affected by these diseases at regular intervals, being mindful of the possibility of SCC development. Furthermore, dermatologists should adopt a lower threshold to biopsy suspicious lesions, especially those that develop within relatively new orolabial DLE, chronic HS, or chronic wound cases, as SCC in these settings is particularly aggressive and displays mortality and metastasis rates that exceed those of common cutaneous SCC.


The Diagnosis: Cutaneous Sarcoidosis

A biopsy of a plaque on the back confirmed cutaneous sarcoidosis (CS). A chest radiograph demonstrated hilar nodes, and a referral was placed for comanagement with a pulmonologist. Histopathology was critical in making the diagnosis, with well-circumscribed noncaseating granulomas present in the dermis. The granulomas in CS often are described as naked, as there are minimal lymphocytes present and plasma cells normally are absent.¹ Because the lungs are the most common site of involvement, a chest radiograph is necessary to examine for systemic sarcoidosis. Laboratory workup is used to evaluate for lymphopenia, hypercalcemia, elevated blood sedimentation rate, and elevated angiotensin- converting enzyme levels, which are common in systemic sarcoidosis.¹

Sarcoidosis is a multisystemic granulomatous disorder with an unknown etiology. It is believed to develop in genetically predisposed individuals as a reaction to unidentified antigens in the environment.¹ Helper T cells (T_H1) respond to these environmental antigens in those who are susceptible, which leads to the disease process, but paradoxically, even with the elevation of cellular immune activity at the sites of the granulomatous inflammation, the peripheral immune response in these patients is suppressed as shown by lymphopenia.²

Cutaneous sarcoidosis is found in approximately one-third of patients with systemic sarcoidosis but can occur without systemic involvement.^1,2 Sarcoidosis is reported worldwide and affects patients of all races and ethnicities, ages, and sexes but does have a higher prevalence among Black individuals in the United States, patients younger than 40 years (peak incidence, 20–29 years of age), and females.² In 80% of patients, CS occurs before systemic sarcoidosis develops, or they may develop simultaneously.¹

Cutaneous sarcoidosis has a wide range of clinical presentations that are classified as specific and nonspecific. Specific lesions in CS contain noncaseating granulomas while nonspecific lesions in CS appear as reactive processes.² The most common specific presentation of CS includes papules that are brown in pigmentation in lighter skin tones and red to violaceous in darker skin tones (Figure). The most common nonspecific skin manifestation is erythema nodosum, which represents a hypersensitivity reaction. Cutaneous sarcoidosis can appear as hypopigmented or hyperpigmented patches or plaques.¹

Treatments for CS vary based on the individual.¹ For milder and more localized cases, topical or intralesional steroids may be used. If systemic sarcoidosis is suspected or if there is diffuse involvement of the skin, systemic steroids, antimalarials (eg, hydroxychloroquine), low-dose methotrexate, minocycline, allopurinol, azathioprine, isotretinoin, tumor necrosis factor α inhibitors, or psoralen plus long-wave UVA radiation may be used. If systemic sarcoidosis is present, referral to a pulmonologist is recommended for co-management.¹

Cutaneous sarcoidosis is known as the “great imitator,” and there are multiple diseases to consider in the differential that are distinguished by the physical findings.¹ In our case of a middle-aged Black woman with indurated plaques, a few diagnoses to consider were psoriasis, discoid lupus erythematosus (DLE), mycosis fungoides (MF), and tinea infection.

Psoriasis is a common disease, and 90% of patients have chronic plaquelike disease with well-demarcated erythematous plaques that have a silver-gray scale and a positive Auspitz sign (also known as pinpoint bleeding).³ Plaques often are distributed on the trunk, limb extensors, and scalp, along with nail changes. Some patients also have joint pain, indicating psoriatic arthritis. The etiology of psoriasis is unknown, but it develops due to unrestrained keratinocyte proliferation and defective differentiation, which leads to histopathology showing regular acanthosis and papillary dermal ectasia with rouleaux. Mild cases typically are treated with topical steroids or vitamin D, while more severe cases are treated with methotrexate, cyclosporine, retinoids, or biologics.³

Discoid lupus erythematosus occurs 4 times more often in Black patients than in White patients. Clinically, DLE begins as well-defined, erythematous, scaly patches that expand with hyperpigmentation at the periphery and leave an atrophic, scarred, hypopigmented center.⁴ It typically is localized to the head and neck, but in cases where it disseminates elsewhere on the body, the risk for systemic lupus erythematosus increases from 1.2% to 28%.5 Histopathology of DLE shows vacuolar degeneration of the basal cell layer in the epidermis along with patchy lymphocytic infiltrate in the dermis. Treatments range from topical steroids for mild cases to antimalarial agents, retinoids, anti-inflammatory drugs, and calcineurin inhibitors for more severe cases.⁴

Although there are multiple types of cutaneous T-cell lymphoma, the most common is MF, which traditionally is nonaggressive. The typical patient with MF is older than 60 years and presents with indolent, ongoing, flat to minimally indurated patches or plaques that have cigarette paper scale. As MF progresses, some plaques grow into tumors and can become more aggressive. Histologically, MF changes based on its clinical stage, with the initial phase showing epidermotropic atypical lymphocytes and later phases showing less epitheliotropic, larger, atypical lymphocytes. The treatment algorithm varies depending on cutaneous T-cell lymphoma staging.⁶

Tinea infections are caused by dermatophytes. In prepubertal children, they predominantly appear as tinea corporis (on the body) or tinea capitis (on the scalp), but in adults they appear as tinea cruris (on the groin), tinea pedis (on the feet), or tinea unguium (on the nails).⁷ Tinea infections classically are known to appear as an annular patch with an active erythematous scaling border and central clearing. The patches can be pruritic. Potassium hydroxide preparation of a skin scraping is a quick test to use in the office; if the results are inconclusive, a culture may be required. Treatment depends on the location of the infection but typically involves either topical or oral antifungal agents.⁷

The Diagnosis: Cutaneous Sarcoidosis

A biopsy of a plaque on the back confirmed cutaneous sarcoidosis (CS). A chest radiograph demonstrated hilar nodes, and a referral was placed for comanagement with a pulmonologist. Histopathology was critical in making the diagnosis, with well-circumscribed noncaseating granulomas present in the dermis. The granulomas in CS often are described as naked, as there are minimal lymphocytes present and plasma cells normally are absent.¹ Because the lungs are the most common site of involvement, a chest radiograph is necessary to examine for systemic sarcoidosis. Laboratory workup is used to evaluate for lymphopenia, hypercalcemia, elevated blood sedimentation rate, and elevated angiotensin- converting enzyme levels, which are common in systemic sarcoidosis.¹

Sarcoidosis is a multisystemic granulomatous disorder with an unknown etiology. It is believed to develop in genetically predisposed individuals as a reaction to unidentified antigens in the environment.¹ Helper T cells (T_H1) respond to these environmental antigens in those who are susceptible, which leads to the disease process, but paradoxically, even with the elevation of cellular immune activity at the sites of the granulomatous inflammation, the peripheral immune response in these patients is suppressed as shown by lymphopenia.²

Cutaneous sarcoidosis is found in approximately one-third of patients with systemic sarcoidosis but can occur without systemic involvement.^1,2 Sarcoidosis is reported worldwide and affects patients of all races and ethnicities, ages, and sexes but does have a higher prevalence among Black individuals in the United States, patients younger than 40 years (peak incidence, 20–29 years of age), and females.² In 80% of patients, CS occurs before systemic sarcoidosis develops, or they may develop simultaneously.¹

Cutaneous sarcoidosis has a wide range of clinical presentations that are classified as specific and nonspecific. Specific lesions in CS contain noncaseating granulomas while nonspecific lesions in CS appear as reactive processes.² The most common specific presentation of CS includes papules that are brown in pigmentation in lighter skin tones and red to violaceous in darker skin tones (Figure). The most common nonspecific skin manifestation is erythema nodosum, which represents a hypersensitivity reaction. Cutaneous sarcoidosis can appear as hypopigmented or hyperpigmented patches or plaques.¹

Treatments for CS vary based on the individual.¹ For milder and more localized cases, topical or intralesional steroids may be used. If systemic sarcoidosis is suspected or if there is diffuse involvement of the skin, systemic steroids, antimalarials (eg, hydroxychloroquine), low-dose methotrexate, minocycline, allopurinol, azathioprine, isotretinoin, tumor necrosis factor α inhibitors, or psoralen plus long-wave UVA radiation may be used. If systemic sarcoidosis is present, referral to a pulmonologist is recommended for co-management.¹

Cutaneous sarcoidosis is known as the “great imitator,” and there are multiple diseases to consider in the differential that are distinguished by the physical findings.¹ In our case of a middle-aged Black woman with indurated plaques, a few diagnoses to consider were psoriasis, discoid lupus erythematosus (DLE), mycosis fungoides (MF), and tinea infection.

Psoriasis is a common disease, and 90% of patients have chronic plaquelike disease with well-demarcated erythematous plaques that have a silver-gray scale and a positive Auspitz sign (also known as pinpoint bleeding).³ Plaques often are distributed on the trunk, limb extensors, and scalp, along with nail changes. Some patients also have joint pain, indicating psoriatic arthritis. The etiology of psoriasis is unknown, but it develops due to unrestrained keratinocyte proliferation and defective differentiation, which leads to histopathology showing regular acanthosis and papillary dermal ectasia with rouleaux. Mild cases typically are treated with topical steroids or vitamin D, while more severe cases are treated with methotrexate, cyclosporine, retinoids, or biologics.³

Discoid lupus erythematosus occurs 4 times more often in Black patients than in White patients. Clinically, DLE begins as well-defined, erythematous, scaly patches that expand with hyperpigmentation at the periphery and leave an atrophic, scarred, hypopigmented center.⁴ It typically is localized to the head and neck, but in cases where it disseminates elsewhere on the body, the risk for systemic lupus erythematosus increases from 1.2% to 28%.5 Histopathology of DLE shows vacuolar degeneration of the basal cell layer in the epidermis along with patchy lymphocytic infiltrate in the dermis. Treatments range from topical steroids for mild cases to antimalarial agents, retinoids, anti-inflammatory drugs, and calcineurin inhibitors for more severe cases.⁴

Although there are multiple types of cutaneous T-cell lymphoma, the most common is MF, which traditionally is nonaggressive. The typical patient with MF is older than 60 years and presents with indolent, ongoing, flat to minimally indurated patches or plaques that have cigarette paper scale. As MF progresses, some plaques grow into tumors and can become more aggressive. Histologically, MF changes based on its clinical stage, with the initial phase showing epidermotropic atypical lymphocytes and later phases showing less epitheliotropic, larger, atypical lymphocytes. The treatment algorithm varies depending on cutaneous T-cell lymphoma staging.⁶

Tinea infections are caused by dermatophytes. In prepubertal children, they predominantly appear as tinea corporis (on the body) or tinea capitis (on the scalp), but in adults they appear as tinea cruris (on the groin), tinea pedis (on the feet), or tinea unguium (on the nails).⁷ Tinea infections classically are known to appear as an annular patch with an active erythematous scaling border and central clearing. The patches can be pruritic. Potassium hydroxide preparation of a skin scraping is a quick test to use in the office; if the results are inconclusive, a culture may be required. Treatment depends on the location of the infection but typically involves either topical or oral antifungal agents.⁷

The Diagnosis: Cutaneous Sarcoidosis

A biopsy of a plaque on the back confirmed cutaneous sarcoidosis (CS). A chest radiograph demonstrated hilar nodes, and a referral was placed for comanagement with a pulmonologist. Histopathology was critical in making the diagnosis, with well-circumscribed noncaseating granulomas present in the dermis. The granulomas in CS often are described as naked, as there are minimal lymphocytes present and plasma cells normally are absent.¹ Because the lungs are the most common site of involvement, a chest radiograph is necessary to examine for systemic sarcoidosis. Laboratory workup is used to evaluate for lymphopenia, hypercalcemia, elevated blood sedimentation rate, and elevated angiotensin- converting enzyme levels, which are common in systemic sarcoidosis.¹

Sarcoidosis is a multisystemic granulomatous disorder with an unknown etiology. It is believed to develop in genetically predisposed individuals as a reaction to unidentified antigens in the environment.¹ Helper T cells (T_H1) respond to these environmental antigens in those who are susceptible, which leads to the disease process, but paradoxically, even with the elevation of cellular immune activity at the sites of the granulomatous inflammation, the peripheral immune response in these patients is suppressed as shown by lymphopenia.²

Cutaneous sarcoidosis is found in approximately one-third of patients with systemic sarcoidosis but can occur without systemic involvement.^1,2 Sarcoidosis is reported worldwide and affects patients of all races and ethnicities, ages, and sexes but does have a higher prevalence among Black individuals in the United States, patients younger than 40 years (peak incidence, 20–29 years of age), and females.² In 80% of patients, CS occurs before systemic sarcoidosis develops, or they may develop simultaneously.¹

Cutaneous sarcoidosis has a wide range of clinical presentations that are classified as specific and nonspecific. Specific lesions in CS contain noncaseating granulomas while nonspecific lesions in CS appear as reactive processes.² The most common specific presentation of CS includes papules that are brown in pigmentation in lighter skin tones and red to violaceous in darker skin tones (Figure). The most common nonspecific skin manifestation is erythema nodosum, which represents a hypersensitivity reaction. Cutaneous sarcoidosis can appear as hypopigmented or hyperpigmented patches or plaques.¹

Treatments for CS vary based on the individual.¹ For milder and more localized cases, topical or intralesional steroids may be used. If systemic sarcoidosis is suspected or if there is diffuse involvement of the skin, systemic steroids, antimalarials (eg, hydroxychloroquine), low-dose methotrexate, minocycline, allopurinol, azathioprine, isotretinoin, tumor necrosis factor α inhibitors, or psoralen plus long-wave UVA radiation may be used. If systemic sarcoidosis is present, referral to a pulmonologist is recommended for co-management.¹

Cutaneous sarcoidosis is known as the “great imitator,” and there are multiple diseases to consider in the differential that are distinguished by the physical findings.¹ In our case of a middle-aged Black woman with indurated plaques, a few diagnoses to consider were psoriasis, discoid lupus erythematosus (DLE), mycosis fungoides (MF), and tinea infection.

Psoriasis is a common disease, and 90% of patients have chronic plaquelike disease with well-demarcated erythematous plaques that have a silver-gray scale and a positive Auspitz sign (also known as pinpoint bleeding).³ Plaques often are distributed on the trunk, limb extensors, and scalp, along with nail changes. Some patients also have joint pain, indicating psoriatic arthritis. The etiology of psoriasis is unknown, but it develops due to unrestrained keratinocyte proliferation and defective differentiation, which leads to histopathology showing regular acanthosis and papillary dermal ectasia with rouleaux. Mild cases typically are treated with topical steroids or vitamin D, while more severe cases are treated with methotrexate, cyclosporine, retinoids, or biologics.³

Discoid lupus erythematosus occurs 4 times more often in Black patients than in White patients. Clinically, DLE begins as well-defined, erythematous, scaly patches that expand with hyperpigmentation at the periphery and leave an atrophic, scarred, hypopigmented center.⁴ It typically is localized to the head and neck, but in cases where it disseminates elsewhere on the body, the risk for systemic lupus erythematosus increases from 1.2% to 28%.5 Histopathology of DLE shows vacuolar degeneration of the basal cell layer in the epidermis along with patchy lymphocytic infiltrate in the dermis. Treatments range from topical steroids for mild cases to antimalarial agents, retinoids, anti-inflammatory drugs, and calcineurin inhibitors for more severe cases.⁴

Although there are multiple types of cutaneous T-cell lymphoma, the most common is MF, which traditionally is nonaggressive. The typical patient with MF is older than 60 years and presents with indolent, ongoing, flat to minimally indurated patches or plaques that have cigarette paper scale. As MF progresses, some plaques grow into tumors and can become more aggressive. Histologically, MF changes based on its clinical stage, with the initial phase showing epidermotropic atypical lymphocytes and later phases showing less epitheliotropic, larger, atypical lymphocytes. The treatment algorithm varies depending on cutaneous T-cell lymphoma staging.⁶

Tinea infections are caused by dermatophytes. In prepubertal children, they predominantly appear as tinea corporis (on the body) or tinea capitis (on the scalp), but in adults they appear as tinea cruris (on the groin), tinea pedis (on the feet), or tinea unguium (on the nails).⁷ Tinea infections classically are known to appear as an annular patch with an active erythematous scaling border and central clearing. The patches can be pruritic. Potassium hydroxide preparation of a skin scraping is a quick test to use in the office; if the results are inconclusive, a culture may be required. Treatment depends on the location of the infection but typically involves either topical or oral antifungal agents.⁷

Clinical Importance

Western poison ivy (Toxicodendron rydbergii) is responsible for many of the cases of Toxicodendron contact dermatitis (TCD) reported in the western and northern United States. Toxicodendron plants cause more cases of allergic contact dermatitis (ACD) in North America than any other allergen¹; 9 million Americans present to physician offices and 1.6 million present to emergency departments annually for ACD, emphasizing the notable medical burden of this condition.^2,3 Exposure to urushiol, a plant resin containing potent allergens, precipitates this form of ACD.

An estimated 50% to 75% of adults in the United States demonstrate clinical sensitivity and exhibit ACD following contact with T rydbergii.⁴ Campers, hikers, firefighters, and forest workers often risk increased exposure through physical contact or aerosolized allergens in smoke. According to the Centers for Disease Control and Prevention, the incidence of visits to US emergency departments for TCD nearly doubled from 2002 to 2012,⁵ which may be explained by atmospheric CO₂ levels that both promote increased growth of Toxicodendron species and augment their toxicity.⁶

Cutaneous Manifestations

The clinical presentation of T rydbergii contact dermatitis is similar to other allergenic members of the Toxicodendron genus. Patients sensitive to urushiol typically develop a pruritic erythematous rash within 1 to 2 days of exposure (range, 5 hours to 15 days).⁷ Erythematous and edematous streaks initially manifest on the extremities and often progress to bullae and oozing papulovesicles. In early disease, patients also may display black lesions on or near the rash⁸ (so-called black-dot dermatitis) caused by oxidized urushiol deposited on the skin—an uncommon yet classic presentation of TCD. Generally, symptoms resolve without complications and with few sequalae, though hyperpigmentation or a secondary infection can develop on or near affected areas.^9,10

Taxonomy

The Toxicodendron genus belongs to the Anacardiaceae family, which includes pistachios, mangos, and cashews, and causes more cases of ACD than every other plant combined.⁴ (Shelled pistachios and cashews do not possess cross-reacting allergens and should not worry consumers; mango skin does contain urushiol.)

Toxicodendron (formerly part of the Rhus genus) includes several species of poison oak, poison ivy, and poison sumac and can be found in shrubs (T rydbergii and Toxicodendron diversilobum), vines (Toxicodendron radicans and Toxicodendron pubescens), and trees (Toxicodendron vernix). In addition, Toxicodendron taxa can hybridize with other taxa in close geographic proximity to form morphologic intermediates. Some individual plants have features of multiple species.¹¹

Etymology

The common name of T rydbergii—western poison ivy—misleads the public; the plant contains no poison that can cause death and does not grow as ivy by wrapping around trees, as T radicans and English ivy (Hedera helix) do. Its formal genus, Toxicodendron, means “poison tree” in Greek and was given its generic name by the English botanist Phillip Miller in 1768,¹² which caused the renaming of Rhus rydbergii as T rydbergii. The species name honors Per Axel Rydberg, a 19th and 20th century Swedish-American botanist.

Distribution

Toxicodendron rydbergii grows in California and other states in the western half of the United States as well as the states bordering Canada and Mexico. In Canada, it reigns as the most dominant form of poison ivy.¹³ Hikers and campers find T rydbergii in a variety of areas, including roadsides, river bottoms, sandy shores, talus slopes, precipices, and floodplains.¹¹ This taxon grows under a variety of conditions and in distinct regions, and it thrives in both full sun or shade.

 

 

Identifying Features

Toxicodendron rydbergii turns red earlier than most plants; early red summer leaves should serve as a warning sign to hikers from a distance (Figure 1). It displays trifoliate ovate leaves (ie, each leaf contains 3 leaflets) on a dwarf nonclimbing shrub (Figure 2). Although the plant shares common features with its cousin T radicans (eastern poison ivy), T rydbergii is easily distinguished by its thicker stems, absence of aerial rootlets (abundant in T radicans), and short (approximately 1 meter) height.⁴

Photograph courtesy of Thomas W. McGovern, MD.

Curly hairs occupy the underside of T rydbergii leaflets and along the midrib; leaflet margins appear lobed or rounded. Lenticels appear as small holes in the bark that turn gray in the cold and become brighter come spring.¹³

Photograph courtesy of Thomas W. McGovern, MD.

The plant bears glabrous long petioles (leaf stems) and densely grouped clusters of yellow flowers. In autumn, the globose fruit—formed in clusters between each twig and leaf petiole (known as an axillary position)—change from yellow-green to tan (Figure 3). When urushiol exudes from damaged leaflets or other plant parts, it oxidizes on exposure to air and creates hardened black deposits on the plant. Even when grown in garden pots, T rydbergii maintains its distinguishing features.¹¹

“Western poison ivy” by Whitney Cranshaw is licensed under CC BY 3.0 (https://creativecommons.org/licenses/by/3.0/us/).

Dermatitis-Inducing Plant Parts

All parts of T rydbergii including leaves, stems, roots, and fruit contain the allergenic sap throughout the year.¹⁴ A person must damage or bruise the plant for urushiol to be released and produce its allergenic effects; softly brushing against undamaged plants typically does not induce dermatitis.⁴

Pathophysiology of Urushiol

Urushiol, a pale yellow, oily mixture of organic compounds conserved throughout all Toxicodendron species, contains highly allergenic alkyl catechols. These catechols possess hydroxyl groups at positions 1 and 2 on a benzene ring; the hydrocarbon side chain of poison ivies (typically 15–carbon atoms long) attaches at position 3.¹⁵ The catechols and the aliphatic side chain contribute to the plant’s antigenic and dermatitis-inducing properties.¹⁶

The high lipophilicity of urushiol allows for rapid and unforgiving absorption into the skin, notwithstanding attempts to wash it off. Upon direct contact, catechols of urushiol penetrate the epidermis and become oxidized to quinone intermediates that bind to antigen-presenting cells in the epidermis and dermis. Epidermal Langerhans cells and dermal macrophages internalize and present the antigen to CD4⁺ T cells in nearby lymph nodes. This sequence results in production of inflammatory mediators, clonal expansion of T-effector and T-memory cells specific to the allergenic catechols, and an ensuing cytotoxic response against epidermal cells and the dermal vasculature. Keratinocytes and monocytes mediate the inflammatory response by releasing other cytokines.^4,17

Sensitization to urushiol generally occurs at 8 to 14 years of age; therefore, infants have lower susceptibility to dermatitis upon contact with T rydbergii.¹⁸ Most animals do not experience sensitization upon contact; in fact, birds and forest animals consume the urushiol-rich fruit of T rydbergii without harm.³

Prevention and Treatment

Toxicodendron dermatitis typically lasts 1 to 3 weeks but can remain for as long as 6 weeks without treatment.¹⁹ Recognition and physical avoidance of the plant provides the most promising preventive strategy. Immediate rinsing with soap and water can prevent TCD by breaking down urushiol and its allergenic components; however, this is an option for only a short time, as the skin absorbs 50% of urushiol within 10 minutes after contact.²⁰ Nevertheless, patients must seize the earliest opportunity to wash off the affected area and remove any residual urushiol. Patients must be cautious when removing and washing clothing to prevent further contact.

Most health care providers treat TCD with a corticosteroid to reduce inflammation and intense pruritus. A high-potency topical corticosteroid (eg, clobetasol) may prove effective in providing early therapeutic relief in mild disease.²¹ A short course of a systemic steroid quickly and effectively quenches intense itching and should not be limited to what the clinician considers severe disease. Do not underestimate the patient’s symptoms with this eruption.

Prednisone dosing begins at 1 mg/kg daily and is then tapered slowly over 2 weeks (no shorter a time) for an optimal treatment course of 15 days.²² Prescribing an inadequate dosage and course of a corticosteroid leaves the patient susceptible to rebound dermatitis—and loss of trust in their provider.

Intramuscular injection of the long-acting corticosteroid triamcinolone acetonide with rapid-onset betamethasone provides rapid relief and fewer adverse effects than an oral corticosteroid.²² Despite the long-standing use of sedating oral antihistamines by clinicians, these drugs provide no benefit for pruritus or sleep because the histamine does not cause the itching of TCD, and antihistamines disrupt normal sleep architecture.^23-25

Patients can consider several over-the-counter products that have varying degrees of efficacy.^4,26 The few products for which prospective studies support their use include Tecnu (Tec Laboraties Inc), Zanfel (RhusTox), and the well-known soaps Dial (Henkel Corporation) and Goop (Critzas Industries, Inc).^27,28

Aside from treating the direct effects of TCD, clinicians also must take note of any look for signs of secondary infection and occasionally should consider supplementing treatment with an antibiotic.

Clinical Importance

Western poison ivy (Toxicodendron rydbergii) is responsible for many of the cases of Toxicodendron contact dermatitis (TCD) reported in the western and northern United States. Toxicodendron plants cause more cases of allergic contact dermatitis (ACD) in North America than any other allergen¹; 9 million Americans present to physician offices and 1.6 million present to emergency departments annually for ACD, emphasizing the notable medical burden of this condition.^2,3 Exposure to urushiol, a plant resin containing potent allergens, precipitates this form of ACD.

An estimated 50% to 75% of adults in the United States demonstrate clinical sensitivity and exhibit ACD following contact with T rydbergii.⁴ Campers, hikers, firefighters, and forest workers often risk increased exposure through physical contact or aerosolized allergens in smoke. According to the Centers for Disease Control and Prevention, the incidence of visits to US emergency departments for TCD nearly doubled from 2002 to 2012,⁵ which may be explained by atmospheric CO₂ levels that both promote increased growth of Toxicodendron species and augment their toxicity.⁶

Cutaneous Manifestations

The clinical presentation of T rydbergii contact dermatitis is similar to other allergenic members of the Toxicodendron genus. Patients sensitive to urushiol typically develop a pruritic erythematous rash within 1 to 2 days of exposure (range, 5 hours to 15 days).⁷ Erythematous and edematous streaks initially manifest on the extremities and often progress to bullae and oozing papulovesicles. In early disease, patients also may display black lesions on or near the rash⁸ (so-called black-dot dermatitis) caused by oxidized urushiol deposited on the skin—an uncommon yet classic presentation of TCD. Generally, symptoms resolve without complications and with few sequalae, though hyperpigmentation or a secondary infection can develop on or near affected areas.^9,10

Taxonomy

The Toxicodendron genus belongs to the Anacardiaceae family, which includes pistachios, mangos, and cashews, and causes more cases of ACD than every other plant combined.⁴ (Shelled pistachios and cashews do not possess cross-reacting allergens and should not worry consumers; mango skin does contain urushiol.)

Toxicodendron (formerly part of the Rhus genus) includes several species of poison oak, poison ivy, and poison sumac and can be found in shrubs (T rydbergii and Toxicodendron diversilobum), vines (Toxicodendron radicans and Toxicodendron pubescens), and trees (Toxicodendron vernix). In addition, Toxicodendron taxa can hybridize with other taxa in close geographic proximity to form morphologic intermediates. Some individual plants have features of multiple species.¹¹

Etymology

The common name of T rydbergii—western poison ivy—misleads the public; the plant contains no poison that can cause death and does not grow as ivy by wrapping around trees, as T radicans and English ivy (Hedera helix) do. Its formal genus, Toxicodendron, means “poison tree” in Greek and was given its generic name by the English botanist Phillip Miller in 1768,¹² which caused the renaming of Rhus rydbergii as T rydbergii. The species name honors Per Axel Rydberg, a 19th and 20th century Swedish-American botanist.

Distribution

Toxicodendron rydbergii grows in California and other states in the western half of the United States as well as the states bordering Canada and Mexico. In Canada, it reigns as the most dominant form of poison ivy.¹³ Hikers and campers find T rydbergii in a variety of areas, including roadsides, river bottoms, sandy shores, talus slopes, precipices, and floodplains.¹¹ This taxon grows under a variety of conditions and in distinct regions, and it thrives in both full sun or shade.

 

 

Identifying Features

Toxicodendron rydbergii turns red earlier than most plants; early red summer leaves should serve as a warning sign to hikers from a distance (Figure 1). It displays trifoliate ovate leaves (ie, each leaf contains 3 leaflets) on a dwarf nonclimbing shrub (Figure 2). Although the plant shares common features with its cousin T radicans (eastern poison ivy), T rydbergii is easily distinguished by its thicker stems, absence of aerial rootlets (abundant in T radicans), and short (approximately 1 meter) height.⁴

Photograph courtesy of Thomas W. McGovern, MD.

Curly hairs occupy the underside of T rydbergii leaflets and along the midrib; leaflet margins appear lobed or rounded. Lenticels appear as small holes in the bark that turn gray in the cold and become brighter come spring.¹³

Photograph courtesy of Thomas W. McGovern, MD.

The plant bears glabrous long petioles (leaf stems) and densely grouped clusters of yellow flowers. In autumn, the globose fruit—formed in clusters between each twig and leaf petiole (known as an axillary position)—change from yellow-green to tan (Figure 3). When urushiol exudes from damaged leaflets or other plant parts, it oxidizes on exposure to air and creates hardened black deposits on the plant. Even when grown in garden pots, T rydbergii maintains its distinguishing features.¹¹

“Western poison ivy” by Whitney Cranshaw is licensed under CC BY 3.0 (https://creativecommons.org/licenses/by/3.0/us/).

Dermatitis-Inducing Plant Parts

All parts of T rydbergii including leaves, stems, roots, and fruit contain the allergenic sap throughout the year.¹⁴ A person must damage or bruise the plant for urushiol to be released and produce its allergenic effects; softly brushing against undamaged plants typically does not induce dermatitis.⁴

Pathophysiology of Urushiol

Urushiol, a pale yellow, oily mixture of organic compounds conserved throughout all Toxicodendron species, contains highly allergenic alkyl catechols. These catechols possess hydroxyl groups at positions 1 and 2 on a benzene ring; the hydrocarbon side chain of poison ivies (typically 15–carbon atoms long) attaches at position 3.¹⁵ The catechols and the aliphatic side chain contribute to the plant’s antigenic and dermatitis-inducing properties.¹⁶

The high lipophilicity of urushiol allows for rapid and unforgiving absorption into the skin, notwithstanding attempts to wash it off. Upon direct contact, catechols of urushiol penetrate the epidermis and become oxidized to quinone intermediates that bind to antigen-presenting cells in the epidermis and dermis. Epidermal Langerhans cells and dermal macrophages internalize and present the antigen to CD4⁺ T cells in nearby lymph nodes. This sequence results in production of inflammatory mediators, clonal expansion of T-effector and T-memory cells specific to the allergenic catechols, and an ensuing cytotoxic response against epidermal cells and the dermal vasculature. Keratinocytes and monocytes mediate the inflammatory response by releasing other cytokines.^4,17

Sensitization to urushiol generally occurs at 8 to 14 years of age; therefore, infants have lower susceptibility to dermatitis upon contact with T rydbergii.¹⁸ Most animals do not experience sensitization upon contact; in fact, birds and forest animals consume the urushiol-rich fruit of T rydbergii without harm.³

Prevention and Treatment

Toxicodendron dermatitis typically lasts 1 to 3 weeks but can remain for as long as 6 weeks without treatment.¹⁹ Recognition and physical avoidance of the plant provides the most promising preventive strategy. Immediate rinsing with soap and water can prevent TCD by breaking down urushiol and its allergenic components; however, this is an option for only a short time, as the skin absorbs 50% of urushiol within 10 minutes after contact.²⁰ Nevertheless, patients must seize the earliest opportunity to wash off the affected area and remove any residual urushiol. Patients must be cautious when removing and washing clothing to prevent further contact.

Most health care providers treat TCD with a corticosteroid to reduce inflammation and intense pruritus. A high-potency topical corticosteroid (eg, clobetasol) may prove effective in providing early therapeutic relief in mild disease.²¹ A short course of a systemic steroid quickly and effectively quenches intense itching and should not be limited to what the clinician considers severe disease. Do not underestimate the patient’s symptoms with this eruption.

Prednisone dosing begins at 1 mg/kg daily and is then tapered slowly over 2 weeks (no shorter a time) for an optimal treatment course of 15 days.²² Prescribing an inadequate dosage and course of a corticosteroid leaves the patient susceptible to rebound dermatitis—and loss of trust in their provider.

Intramuscular injection of the long-acting corticosteroid triamcinolone acetonide with rapid-onset betamethasone provides rapid relief and fewer adverse effects than an oral corticosteroid.²² Despite the long-standing use of sedating oral antihistamines by clinicians, these drugs provide no benefit for pruritus or sleep because the histamine does not cause the itching of TCD, and antihistamines disrupt normal sleep architecture.^23-25

Patients can consider several over-the-counter products that have varying degrees of efficacy.^4,26 The few products for which prospective studies support their use include Tecnu (Tec Laboraties Inc), Zanfel (RhusTox), and the well-known soaps Dial (Henkel Corporation) and Goop (Critzas Industries, Inc).^27,28

Aside from treating the direct effects of TCD, clinicians also must take note of any look for signs of secondary infection and occasionally should consider supplementing treatment with an antibiotic.

Clinical Importance

Western poison ivy (Toxicodendron rydbergii) is responsible for many of the cases of Toxicodendron contact dermatitis (TCD) reported in the western and northern United States. Toxicodendron plants cause more cases of allergic contact dermatitis (ACD) in North America than any other allergen¹; 9 million Americans present to physician offices and 1.6 million present to emergency departments annually for ACD, emphasizing the notable medical burden of this condition.^2,3 Exposure to urushiol, a plant resin containing potent allergens, precipitates this form of ACD.

An estimated 50% to 75% of adults in the United States demonstrate clinical sensitivity and exhibit ACD following contact with T rydbergii.⁴ Campers, hikers, firefighters, and forest workers often risk increased exposure through physical contact or aerosolized allergens in smoke. According to the Centers for Disease Control and Prevention, the incidence of visits to US emergency departments for TCD nearly doubled from 2002 to 2012,⁵ which may be explained by atmospheric CO₂ levels that both promote increased growth of Toxicodendron species and augment their toxicity.⁶

Cutaneous Manifestations

The clinical presentation of T rydbergii contact dermatitis is similar to other allergenic members of the Toxicodendron genus. Patients sensitive to urushiol typically develop a pruritic erythematous rash within 1 to 2 days of exposure (range, 5 hours to 15 days).⁷ Erythematous and edematous streaks initially manifest on the extremities and often progress to bullae and oozing papulovesicles. In early disease, patients also may display black lesions on or near the rash⁸ (so-called black-dot dermatitis) caused by oxidized urushiol deposited on the skin—an uncommon yet classic presentation of TCD. Generally, symptoms resolve without complications and with few sequalae, though hyperpigmentation or a secondary infection can develop on or near affected areas.^9,10

Taxonomy

The Toxicodendron genus belongs to the Anacardiaceae family, which includes pistachios, mangos, and cashews, and causes more cases of ACD than every other plant combined.⁴ (Shelled pistachios and cashews do not possess cross-reacting allergens and should not worry consumers; mango skin does contain urushiol.)

Toxicodendron (formerly part of the Rhus genus) includes several species of poison oak, poison ivy, and poison sumac and can be found in shrubs (T rydbergii and Toxicodendron diversilobum), vines (Toxicodendron radicans and Toxicodendron pubescens), and trees (Toxicodendron vernix). In addition, Toxicodendron taxa can hybridize with other taxa in close geographic proximity to form morphologic intermediates. Some individual plants have features of multiple species.¹¹

Etymology

The common name of T rydbergii—western poison ivy—misleads the public; the plant contains no poison that can cause death and does not grow as ivy by wrapping around trees, as T radicans and English ivy (Hedera helix) do. Its formal genus, Toxicodendron, means “poison tree” in Greek and was given its generic name by the English botanist Phillip Miller in 1768,¹² which caused the renaming of Rhus rydbergii as T rydbergii. The species name honors Per Axel Rydberg, a 19th and 20th century Swedish-American botanist.

Distribution

Toxicodendron rydbergii grows in California and other states in the western half of the United States as well as the states bordering Canada and Mexico. In Canada, it reigns as the most dominant form of poison ivy.¹³ Hikers and campers find T rydbergii in a variety of areas, including roadsides, river bottoms, sandy shores, talus slopes, precipices, and floodplains.¹¹ This taxon grows under a variety of conditions and in distinct regions, and it thrives in both full sun or shade.

 

 

Identifying Features

Toxicodendron rydbergii turns red earlier than most plants; early red summer leaves should serve as a warning sign to hikers from a distance (Figure 1). It displays trifoliate ovate leaves (ie, each leaf contains 3 leaflets) on a dwarf nonclimbing shrub (Figure 2). Although the plant shares common features with its cousin T radicans (eastern poison ivy), T rydbergii is easily distinguished by its thicker stems, absence of aerial rootlets (abundant in T radicans), and short (approximately 1 meter) height.⁴

Photograph courtesy of Thomas W. McGovern, MD.

Curly hairs occupy the underside of T rydbergii leaflets and along the midrib; leaflet margins appear lobed or rounded. Lenticels appear as small holes in the bark that turn gray in the cold and become brighter come spring.¹³

Photograph courtesy of Thomas W. McGovern, MD.

The plant bears glabrous long petioles (leaf stems) and densely grouped clusters of yellow flowers. In autumn, the globose fruit—formed in clusters between each twig and leaf petiole (known as an axillary position)—change from yellow-green to tan (Figure 3). When urushiol exudes from damaged leaflets or other plant parts, it oxidizes on exposure to air and creates hardened black deposits on the plant. Even when grown in garden pots, T rydbergii maintains its distinguishing features.¹¹

“Western poison ivy” by Whitney Cranshaw is licensed under CC BY 3.0 (https://creativecommons.org/licenses/by/3.0/us/).

Dermatitis-Inducing Plant Parts

All parts of T rydbergii including leaves, stems, roots, and fruit contain the allergenic sap throughout the year.¹⁴ A person must damage or bruise the plant for urushiol to be released and produce its allergenic effects; softly brushing against undamaged plants typically does not induce dermatitis.⁴

Pathophysiology of Urushiol

Urushiol, a pale yellow, oily mixture of organic compounds conserved throughout all Toxicodendron species, contains highly allergenic alkyl catechols. These catechols possess hydroxyl groups at positions 1 and 2 on a benzene ring; the hydrocarbon side chain of poison ivies (typically 15–carbon atoms long) attaches at position 3.¹⁵ The catechols and the aliphatic side chain contribute to the plant’s antigenic and dermatitis-inducing properties.¹⁶

The high lipophilicity of urushiol allows for rapid and unforgiving absorption into the skin, notwithstanding attempts to wash it off. Upon direct contact, catechols of urushiol penetrate the epidermis and become oxidized to quinone intermediates that bind to antigen-presenting cells in the epidermis and dermis. Epidermal Langerhans cells and dermal macrophages internalize and present the antigen to CD4⁺ T cells in nearby lymph nodes. This sequence results in production of inflammatory mediators, clonal expansion of T-effector and T-memory cells specific to the allergenic catechols, and an ensuing cytotoxic response against epidermal cells and the dermal vasculature. Keratinocytes and monocytes mediate the inflammatory response by releasing other cytokines.^4,17

Sensitization to urushiol generally occurs at 8 to 14 years of age; therefore, infants have lower susceptibility to dermatitis upon contact with T rydbergii.¹⁸ Most animals do not experience sensitization upon contact; in fact, birds and forest animals consume the urushiol-rich fruit of T rydbergii without harm.³

Prevention and Treatment

Toxicodendron dermatitis typically lasts 1 to 3 weeks but can remain for as long as 6 weeks without treatment.¹⁹ Recognition and physical avoidance of the plant provides the most promising preventive strategy. Immediate rinsing with soap and water can prevent TCD by breaking down urushiol and its allergenic components; however, this is an option for only a short time, as the skin absorbs 50% of urushiol within 10 minutes after contact.²⁰ Nevertheless, patients must seize the earliest opportunity to wash off the affected area and remove any residual urushiol. Patients must be cautious when removing and washing clothing to prevent further contact.

Most health care providers treat TCD with a corticosteroid to reduce inflammation and intense pruritus. A high-potency topical corticosteroid (eg, clobetasol) may prove effective in providing early therapeutic relief in mild disease.²¹ A short course of a systemic steroid quickly and effectively quenches intense itching and should not be limited to what the clinician considers severe disease. Do not underestimate the patient’s symptoms with this eruption.

Prednisone dosing begins at 1 mg/kg daily and is then tapered slowly over 2 weeks (no shorter a time) for an optimal treatment course of 15 days.²² Prescribing an inadequate dosage and course of a corticosteroid leaves the patient susceptible to rebound dermatitis—and loss of trust in their provider.

Intramuscular injection of the long-acting corticosteroid triamcinolone acetonide with rapid-onset betamethasone provides rapid relief and fewer adverse effects than an oral corticosteroid.²² Despite the long-standing use of sedating oral antihistamines by clinicians, these drugs provide no benefit for pruritus or sleep because the histamine does not cause the itching of TCD, and antihistamines disrupt normal sleep architecture.^23-25

Patients can consider several over-the-counter products that have varying degrees of efficacy.^4,26 The few products for which prospective studies support their use include Tecnu (Tec Laboraties Inc), Zanfel (RhusTox), and the well-known soaps Dial (Henkel Corporation) and Goop (Critzas Industries, Inc).^27,28

Aside from treating the direct effects of TCD, clinicians also must take note of any look for signs of secondary infection and occasionally should consider supplementing treatment with an antibiotic.

To the Editor:

Pyogenic granuloma (PG) is a benign vascular tumor that clinically is characterized as a small eruptive friable papule.¹ Lesions typically are solitary and most commonly occur in children but also are associated with pregnancy; trauma to the skin or mucosa; and use of certain medications such as isotretinoin, capecitabine, vemurafenib, or indinavir.¹ Numerous antineoplastic medications have been associated with the development of solitary PGs, including the taxane mitotic inhibitor paclitaxel (PTX) and the vascular endothelial growth factor receptor 2 (VEGFR2) monoclonal antibody ramucirumab.² We report a case of multiple PGs in a patient undergoing treatment with PTX and ramucirumab.

A 59-year-old woman presented to the dermatology clinic with red, itchy, bleeding skin lesions on the breast, superior chest, left cheek, and forearm of 1 month’s duration. She denied any preceding trauma to the areas. Her medical history was notable for gastroesophageal junction adenocarcinoma diagnosed more than 2 years prior to presentation. Her original treatment regimen included nivolumab, which was discontinued for unknown reasons 5 months prior to presentation, and she was started on combination therapy with PTX and ramucirumab at that time. She noted the formation of small red papules 2 months after the initiation of PTX-ramucirumab combination therapy, which grew larger over the course of the next month. Physical examination revealed 5 friable hemorrhagic papules and nodules ranging in size from 3 to 10 mm on the chest, cheek, and forearm consistent with PGs (Figure 1). Several scattered cherry angiomas were noted on the scalp and torso, but the patient reported these were not new. Biopsies of the PGs demonstrated lobular aggregates of small-caliber vessels set in an edematous inflamed stroma and partially enclosed by small collarettes of adnexal epithelium, confirming the clinical diagnosis of multiple PGs (Figure 2).

The first case of PTX-associated PG was reported in 2012.³ Based on a PubMed search of articles indexed for MEDLINE using the terms pyogenic granuloma, lobular capillary hemangioma, paclitaxel, taxane, and ramucirumab, there have been 9 cases of solitary PG development in the setting of PTX alone or in combination with ramucirumab since 2019 (Table).^3-8 Pyogenic granulomas reported in patients who were treated exclusively with PTX were subungual, while the cases resulting from combined therapy were present on the scalp, face, oral mucosa, and surfaces of the hands sparing the nails. Ibe et al⁶ reported PG in a patient who received ramucirumab therapy without PTX but in combination with another taxane, docetaxel, which itself has been reported to cause subungual PG when used alone.⁹ Our case of the simultaneous development of multiple PGs in the setting of combined PTX and ramucirumab therapy added to the cutaneous distributions for which therapy-induced PGs have been observed (Table).

The development of PG, a vascular tumor, during treatment with the VEGFR2 inhibitor ramucirumab—whose mechanism of action is to inhibit angioneogenesis—is inherently paradoxical. In 2015, a rapidly expanding angioma with a mutation in the kinase domain receptor gene, KDR, that encodes VEGFR2 was identified in a patient undergoing ramucirumab therapy. The authors suggested that KDR mutation resulted in paradoxical activation of VEGFR2 in the setting of ramucirumab therapy.¹⁰ Since then, ramucirumab and PTX were suggested to have a synergistic effect in vascular proliferation,⁵ though an exact mechanism has not been proposed. Other authors have identified increased expression of VEGFR2 in biopsy specimens of PG during combined ramucirumab and taxane therapy.⁶ Although genetic studies have not been used to evaluate for the presence of KDR mutations specifically in our patient population, it is possible that patients who develop PG and other vascular tumors during combined taxane and ramucirumab therapy have a mutation that makes them more susceptible to VEGFR2 upregulation. UV exposure may have a role in the formation of PG in patients on combined ramucirumab and taxane therapy⁷; however, our patient’s lesions were distributed on both sun-exposed and unexposed areas. Although potential clinical implications have not yet been thoroughly investigated, following long-term outcomes for these patients may provide important information on the efficacy of the antineoplastic regimen in the subset of patients who develop cutaneous vascular tumors during antiangiogenic treatment.

Combination therapy with PTX and ramucirumab has been associated with the paradoxical development of cutaneous vascular tumors. We report a case of multiple new-onset PGs in a patient undergoing this treatment regimen.

To the Editor:

Pyogenic granuloma (PG) is a benign vascular tumor that clinically is characterized as a small eruptive friable papule.¹ Lesions typically are solitary and most commonly occur in children but also are associated with pregnancy; trauma to the skin or mucosa; and use of certain medications such as isotretinoin, capecitabine, vemurafenib, or indinavir.¹ Numerous antineoplastic medications have been associated with the development of solitary PGs, including the taxane mitotic inhibitor paclitaxel (PTX) and the vascular endothelial growth factor receptor 2 (VEGFR2) monoclonal antibody ramucirumab.² We report a case of multiple PGs in a patient undergoing treatment with PTX and ramucirumab.

A 59-year-old woman presented to the dermatology clinic with red, itchy, bleeding skin lesions on the breast, superior chest, left cheek, and forearm of 1 month’s duration. She denied any preceding trauma to the areas. Her medical history was notable for gastroesophageal junction adenocarcinoma diagnosed more than 2 years prior to presentation. Her original treatment regimen included nivolumab, which was discontinued for unknown reasons 5 months prior to presentation, and she was started on combination therapy with PTX and ramucirumab at that time. She noted the formation of small red papules 2 months after the initiation of PTX-ramucirumab combination therapy, which grew larger over the course of the next month. Physical examination revealed 5 friable hemorrhagic papules and nodules ranging in size from 3 to 10 mm on the chest, cheek, and forearm consistent with PGs (Figure 1). Several scattered cherry angiomas were noted on the scalp and torso, but the patient reported these were not new. Biopsies of the PGs demonstrated lobular aggregates of small-caliber vessels set in an edematous inflamed stroma and partially enclosed by small collarettes of adnexal epithelium, confirming the clinical diagnosis of multiple PGs (Figure 2).

The first case of PTX-associated PG was reported in 2012.³ Based on a PubMed search of articles indexed for MEDLINE using the terms pyogenic granuloma, lobular capillary hemangioma, paclitaxel, taxane, and ramucirumab, there have been 9 cases of solitary PG development in the setting of PTX alone or in combination with ramucirumab since 2019 (Table).^3-8 Pyogenic granulomas reported in patients who were treated exclusively with PTX were subungual, while the cases resulting from combined therapy were present on the scalp, face, oral mucosa, and surfaces of the hands sparing the nails. Ibe et al⁶ reported PG in a patient who received ramucirumab therapy without PTX but in combination with another taxane, docetaxel, which itself has been reported to cause subungual PG when used alone.⁹ Our case of the simultaneous development of multiple PGs in the setting of combined PTX and ramucirumab therapy added to the cutaneous distributions for which therapy-induced PGs have been observed (Table).

The development of PG, a vascular tumor, during treatment with the VEGFR2 inhibitor ramucirumab—whose mechanism of action is to inhibit angioneogenesis—is inherently paradoxical. In 2015, a rapidly expanding angioma with a mutation in the kinase domain receptor gene, KDR, that encodes VEGFR2 was identified in a patient undergoing ramucirumab therapy. The authors suggested that KDR mutation resulted in paradoxical activation of VEGFR2 in the setting of ramucirumab therapy.¹⁰ Since then, ramucirumab and PTX were suggested to have a synergistic effect in vascular proliferation,⁵ though an exact mechanism has not been proposed. Other authors have identified increased expression of VEGFR2 in biopsy specimens of PG during combined ramucirumab and taxane therapy.⁶ Although genetic studies have not been used to evaluate for the presence of KDR mutations specifically in our patient population, it is possible that patients who develop PG and other vascular tumors during combined taxane and ramucirumab therapy have a mutation that makes them more susceptible to VEGFR2 upregulation. UV exposure may have a role in the formation of PG in patients on combined ramucirumab and taxane therapy⁷; however, our patient’s lesions were distributed on both sun-exposed and unexposed areas. Although potential clinical implications have not yet been thoroughly investigated, following long-term outcomes for these patients may provide important information on the efficacy of the antineoplastic regimen in the subset of patients who develop cutaneous vascular tumors during antiangiogenic treatment.

Combination therapy with PTX and ramucirumab has been associated with the paradoxical development of cutaneous vascular tumors. We report a case of multiple new-onset PGs in a patient undergoing this treatment regimen.

To the Editor:

Pyogenic granuloma (PG) is a benign vascular tumor that clinically is characterized as a small eruptive friable papule.¹ Lesions typically are solitary and most commonly occur in children but also are associated with pregnancy; trauma to the skin or mucosa; and use of certain medications such as isotretinoin, capecitabine, vemurafenib, or indinavir.¹ Numerous antineoplastic medications have been associated with the development of solitary PGs, including the taxane mitotic inhibitor paclitaxel (PTX) and the vascular endothelial growth factor receptor 2 (VEGFR2) monoclonal antibody ramucirumab.² We report a case of multiple PGs in a patient undergoing treatment with PTX and ramucirumab.

A 59-year-old woman presented to the dermatology clinic with red, itchy, bleeding skin lesions on the breast, superior chest, left cheek, and forearm of 1 month’s duration. She denied any preceding trauma to the areas. Her medical history was notable for gastroesophageal junction adenocarcinoma diagnosed more than 2 years prior to presentation. Her original treatment regimen included nivolumab, which was discontinued for unknown reasons 5 months prior to presentation, and she was started on combination therapy with PTX and ramucirumab at that time. She noted the formation of small red papules 2 months after the initiation of PTX-ramucirumab combination therapy, which grew larger over the course of the next month. Physical examination revealed 5 friable hemorrhagic papules and nodules ranging in size from 3 to 10 mm on the chest, cheek, and forearm consistent with PGs (Figure 1). Several scattered cherry angiomas were noted on the scalp and torso, but the patient reported these were not new. Biopsies of the PGs demonstrated lobular aggregates of small-caliber vessels set in an edematous inflamed stroma and partially enclosed by small collarettes of adnexal epithelium, confirming the clinical diagnosis of multiple PGs (Figure 2).

The first case of PTX-associated PG was reported in 2012.³ Based on a PubMed search of articles indexed for MEDLINE using the terms pyogenic granuloma, lobular capillary hemangioma, paclitaxel, taxane, and ramucirumab, there have been 9 cases of solitary PG development in the setting of PTX alone or in combination with ramucirumab since 2019 (Table).^3-8 Pyogenic granulomas reported in patients who were treated exclusively with PTX were subungual, while the cases resulting from combined therapy were present on the scalp, face, oral mucosa, and surfaces of the hands sparing the nails. Ibe et al⁶ reported PG in a patient who received ramucirumab therapy without PTX but in combination with another taxane, docetaxel, which itself has been reported to cause subungual PG when used alone.⁹ Our case of the simultaneous development of multiple PGs in the setting of combined PTX and ramucirumab therapy added to the cutaneous distributions for which therapy-induced PGs have been observed (Table).

The development of PG, a vascular tumor, during treatment with the VEGFR2 inhibitor ramucirumab—whose mechanism of action is to inhibit angioneogenesis—is inherently paradoxical. In 2015, a rapidly expanding angioma with a mutation in the kinase domain receptor gene, KDR, that encodes VEGFR2 was identified in a patient undergoing ramucirumab therapy. The authors suggested that KDR mutation resulted in paradoxical activation of VEGFR2 in the setting of ramucirumab therapy.¹⁰ Since then, ramucirumab and PTX were suggested to have a synergistic effect in vascular proliferation,⁵ though an exact mechanism has not been proposed. Other authors have identified increased expression of VEGFR2 in biopsy specimens of PG during combined ramucirumab and taxane therapy.⁶ Although genetic studies have not been used to evaluate for the presence of KDR mutations specifically in our patient population, it is possible that patients who develop PG and other vascular tumors during combined taxane and ramucirumab therapy have a mutation that makes them more susceptible to VEGFR2 upregulation. UV exposure may have a role in the formation of PG in patients on combined ramucirumab and taxane therapy⁷; however, our patient’s lesions were distributed on both sun-exposed and unexposed areas. Although potential clinical implications have not yet been thoroughly investigated, following long-term outcomes for these patients may provide important information on the efficacy of the antineoplastic regimen in the subset of patients who develop cutaneous vascular tumors during antiangiogenic treatment.

Combination therapy with PTX and ramucirumab has been associated with the paradoxical development of cutaneous vascular tumors. We report a case of multiple new-onset PGs in a patient undergoing this treatment regimen.

To the Editor:

Treatment of cancer, including cutaneous malignancy, has been transformed by the use of immunotherapeutic agents such as immune checkpoint inhibitors (ICIs) that target cytotoxic T lymphocyte-associated antigen 4, programmed cell-death protein 1 (PD-1), or programmed cell-death ligand 1 (PD-L1). However, these drugs are associated with a distinct set of immune-related adverse events (IRAEs). We present a case of generalized eruptive keratoacanthoma of Grzybowski associated with the ICI cemiplimab.

A 94-year-old White woman presented to the dermatology clinic with acute onset of extensive, locally advanced cutaneous squamous cell carcinoma (cSCC) of the upper right posterolateral calf as well as multiple noninvasive cSCCs of the arms and legs. Her medical history was remarkable for widespread actinic keratoses and numerous cSCCs. The patient had no personal or family history of melanoma. Various cSCCs had required treatment with electrodesiccation and curettage, topical or intralesional 5-fluorouracil, and Mohs micrographic surgery. Approximately 1 year prior to presentation, oral acitretin was initiated to help control the cSCC. Given the extent of locally advanced disease, which was considered unresectable, she was referred to oncology but continued to follow up with dermatology. Positron emission tomography was remarkable for hypermetabolic cutaneous thickening in the upper right posterolateral calf with no evidence of visceral disease.

The patient was started on cemiplimab, an anti-PD-1 monoclonal antibody ICI indicated for the treatment of both metastatic and advanced cSCC. After 4 cycles of intravenous cemiplimab, the patient developed widespread nodules covering the arms and legs (Figure 1) as well as associated tenderness and pruritus. Biopsies of nodules revealed superficially invasive, well-differentiated cSCC consistent with keratoacanthoma. Although a lymphocytic infiltrate was present, no other specific reaction pattern, such as a lichenoid infiltrate, was present (Figure 2).

Positron emission tomography was repeated, demonstrating resolution of the right calf lesion; however, new diffuse cutaneous lesions and inguinal lymph node involvement were present, again without evidence of visceral disease. Given the clinical and histologic findings, a diagnosis of generalized eruptive keratoacanthoma of Grzybowski was made. Cemiplimab was discontinued after the fifth cycle. The patient declined further systemic treatment, instead choosing a regimen of topical steroids and an emollient. 

Immunotherapeutics have transformed cancer therapy, which includes ICIs that target cytotoxic T lymphocyte-associated antigen 4, PD-1, or PD-L1. Increased activity of these checkpoints allows tumor cells to downregulate T-cell activation, thereby evading immune destruction. When PD-1 on T cells binds PD-L1 on tumor cells, T lymphocytes are inhibited from cytotoxic-mediated killing. Therefore, anti-PD-1 ICIs such as cemiplimab permit T-lymphocyte activation and destruction of malignant cells. However, this unique mechanism of immunotherapy is associated with an array of IRAEs, which often manifest in a delayed and prolonged fashion.¹ Immune-related adverse events most commonly affect the gastrointestinal tract as well as the endocrine and dermatologic systems.² Notably, patients with certain tumors who experience these adverse effects might be more likely to have superior overall survival; therefore, IRAEs are sometimes used as an indicator of favorable treatment response.^2,3

Dermatologic IRAEs associated with the use of a PD-1 inhibitor include lichenoid reactions, pruritus, morbilliform eruptions, vitiligo, and bullous pemphigoid.^4,5 Eruptions of keratoacanthoma rarely have been reported following treatment with the PD-1 inhibitors nivolumab and pembrolizumab.^3,6,7 In our patient, we believe the profound and generalized eruptive keratoacanthoma—a well-differentiated cSCC variant—was related to treatment of locally advanced cSCC with cemiplimab. The mechanism underlying the formation of anti-PD-1 eruptive keratoacanthoma is not well understood. In susceptible patients, it is plausible that the inflammatory environment permitted by ICIs paradoxically induces regression of tumors such as locally invasive cSCC and simultaneously promotes formation of keratoacanthoma.

The role of inflammation in the pathogenesis and progression of cSCC is complex and possibly involves contrasting roles of leukocyte subpopulations.⁸ The increased incidence of cSCC in the immunocompromised population,⁸ PD-L1 overexpression in cSCC,^9,10 and successful treatment of cSCC with PD-1 inhibition¹⁰ all suggest that inhibition of specific inflammatory pathways is pivotal in tumor pathogenesis. However, increased inflammation, particularly inflammation driven by T lymphocytes and Langerhans cells, also is believed to play a key role in the formation of cSCCs, including the degeneration of actinic keratosis into cSCC. Moreover, because keratoacanthomas are believed to be a cSCC variant and also are associated with PD-L1 overexpression,⁹ it is perplexing that PD-1 blockade may result in eruptive keratoacanthoma in some patients while also treating locally advanced cSCC, as seen in our patient. Successful treatment of keratoacanthoma with anti-inflammatory intralesional or topical corticosteroids adds to this complicated picture.³

We hypothesize that the pathogenesis of invasive cSCC and keratoacanthoma shares certain immune-mediated mechanisms but also differs in distinct manners. To understand the relationship between systemic treatment of cSCC and eruptive keratoacanthoma, further research is required.

In addition, the RAS/BRAF/MEK oncogenic pathway may be involved in the development of cSCCs associated with anti-PD-1. It is hypothesized that BRAF and MEK inhibition increases T-cell infiltration and increases PD-L1 expression on tumor cells,¹¹ thus increasing the susceptibility of those cells to PD-1 blockade. Further supporting a relationship between the RAS/BRAF/MEK and PD-1 pathways, BRAF inhibitors are associated with development of SCCs and verrucal keratosis by upregulation of the RAS pathway.^12,13 Perhaps a common mechanism underlying these pathways results in their shared association for an increased risk for cSCC upon blockade. More research is needed to fully elucidate the underlying biochemical mechanism of immunotherapy and formation of SCCs, such as keratoacanthoma. 

Treatment of solitary keratoacanthoma often involves surgical excision; however, the sheer number of lesions in eruptive keratoacanthoma presents a larger dilemma. Because oral systemic retinoids have been shown to be most effective for treating eruptive keratoacanthoma, they are considered first-line therapy as monotherapy or in combination with surgical excision.³ Other treatment options include intralesional or topical corticosteroids, cyclosporine, 5-fluorouracil, imiquimod, and cryotherapy.^3,6

The development of ICIs has revolutionized the treatment of cutaneous malignancy, yet we have a great deal more to comprehend on the systemic effects of these medications. Although IRAEs may signal a better response to therapy, some of these effects regrettably can be dose limiting. In our patient, cemiplimab was successful in treating locally advanced cSCC, but treatment also resulted in devastating widespread eruptive keratoacanthoma. The mechanism of this kind of eruption has yet to be understood; we hypothesize that it likely involves T lymphocyte–driven inflammation and the interplay of molecular and immune-mediated pathways.

To the Editor:

Treatment of cancer, including cutaneous malignancy, has been transformed by the use of immunotherapeutic agents such as immune checkpoint inhibitors (ICIs) that target cytotoxic T lymphocyte-associated antigen 4, programmed cell-death protein 1 (PD-1), or programmed cell-death ligand 1 (PD-L1). However, these drugs are associated with a distinct set of immune-related adverse events (IRAEs). We present a case of generalized eruptive keratoacanthoma of Grzybowski associated with the ICI cemiplimab.

A 94-year-old White woman presented to the dermatology clinic with acute onset of extensive, locally advanced cutaneous squamous cell carcinoma (cSCC) of the upper right posterolateral calf as well as multiple noninvasive cSCCs of the arms and legs. Her medical history was remarkable for widespread actinic keratoses and numerous cSCCs. The patient had no personal or family history of melanoma. Various cSCCs had required treatment with electrodesiccation and curettage, topical or intralesional 5-fluorouracil, and Mohs micrographic surgery. Approximately 1 year prior to presentation, oral acitretin was initiated to help control the cSCC. Given the extent of locally advanced disease, which was considered unresectable, she was referred to oncology but continued to follow up with dermatology. Positron emission tomography was remarkable for hypermetabolic cutaneous thickening in the upper right posterolateral calf with no evidence of visceral disease.

The patient was started on cemiplimab, an anti-PD-1 monoclonal antibody ICI indicated for the treatment of both metastatic and advanced cSCC. After 4 cycles of intravenous cemiplimab, the patient developed widespread nodules covering the arms and legs (Figure 1) as well as associated tenderness and pruritus. Biopsies of nodules revealed superficially invasive, well-differentiated cSCC consistent with keratoacanthoma. Although a lymphocytic infiltrate was present, no other specific reaction pattern, such as a lichenoid infiltrate, was present (Figure 2).

Positron emission tomography was repeated, demonstrating resolution of the right calf lesion; however, new diffuse cutaneous lesions and inguinal lymph node involvement were present, again without evidence of visceral disease. Given the clinical and histologic findings, a diagnosis of generalized eruptive keratoacanthoma of Grzybowski was made. Cemiplimab was discontinued after the fifth cycle. The patient declined further systemic treatment, instead choosing a regimen of topical steroids and an emollient. 

Immunotherapeutics have transformed cancer therapy, which includes ICIs that target cytotoxic T lymphocyte-associated antigen 4, PD-1, or PD-L1. Increased activity of these checkpoints allows tumor cells to downregulate T-cell activation, thereby evading immune destruction. When PD-1 on T cells binds PD-L1 on tumor cells, T lymphocytes are inhibited from cytotoxic-mediated killing. Therefore, anti-PD-1 ICIs such as cemiplimab permit T-lymphocyte activation and destruction of malignant cells. However, this unique mechanism of immunotherapy is associated with an array of IRAEs, which often manifest in a delayed and prolonged fashion.¹ Immune-related adverse events most commonly affect the gastrointestinal tract as well as the endocrine and dermatologic systems.² Notably, patients with certain tumors who experience these adverse effects might be more likely to have superior overall survival; therefore, IRAEs are sometimes used as an indicator of favorable treatment response.^2,3

Dermatologic IRAEs associated with the use of a PD-1 inhibitor include lichenoid reactions, pruritus, morbilliform eruptions, vitiligo, and bullous pemphigoid.^4,5 Eruptions of keratoacanthoma rarely have been reported following treatment with the PD-1 inhibitors nivolumab and pembrolizumab.^3,6,7 In our patient, we believe the profound and generalized eruptive keratoacanthoma—a well-differentiated cSCC variant—was related to treatment of locally advanced cSCC with cemiplimab. The mechanism underlying the formation of anti-PD-1 eruptive keratoacanthoma is not well understood. In susceptible patients, it is plausible that the inflammatory environment permitted by ICIs paradoxically induces regression of tumors such as locally invasive cSCC and simultaneously promotes formation of keratoacanthoma.

The role of inflammation in the pathogenesis and progression of cSCC is complex and possibly involves contrasting roles of leukocyte subpopulations.⁸ The increased incidence of cSCC in the immunocompromised population,⁸ PD-L1 overexpression in cSCC,^9,10 and successful treatment of cSCC with PD-1 inhibition¹⁰ all suggest that inhibition of specific inflammatory pathways is pivotal in tumor pathogenesis. However, increased inflammation, particularly inflammation driven by T lymphocytes and Langerhans cells, also is believed to play a key role in the formation of cSCCs, including the degeneration of actinic keratosis into cSCC. Moreover, because keratoacanthomas are believed to be a cSCC variant and also are associated with PD-L1 overexpression,⁹ it is perplexing that PD-1 blockade may result in eruptive keratoacanthoma in some patients while also treating locally advanced cSCC, as seen in our patient. Successful treatment of keratoacanthoma with anti-inflammatory intralesional or topical corticosteroids adds to this complicated picture.³

We hypothesize that the pathogenesis of invasive cSCC and keratoacanthoma shares certain immune-mediated mechanisms but also differs in distinct manners. To understand the relationship between systemic treatment of cSCC and eruptive keratoacanthoma, further research is required.

In addition, the RAS/BRAF/MEK oncogenic pathway may be involved in the development of cSCCs associated with anti-PD-1. It is hypothesized that BRAF and MEK inhibition increases T-cell infiltration and increases PD-L1 expression on tumor cells,¹¹ thus increasing the susceptibility of those cells to PD-1 blockade. Further supporting a relationship between the RAS/BRAF/MEK and PD-1 pathways, BRAF inhibitors are associated with development of SCCs and verrucal keratosis by upregulation of the RAS pathway.^12,13 Perhaps a common mechanism underlying these pathways results in their shared association for an increased risk for cSCC upon blockade. More research is needed to fully elucidate the underlying biochemical mechanism of immunotherapy and formation of SCCs, such as keratoacanthoma. 

Treatment of solitary keratoacanthoma often involves surgical excision; however, the sheer number of lesions in eruptive keratoacanthoma presents a larger dilemma. Because oral systemic retinoids have been shown to be most effective for treating eruptive keratoacanthoma, they are considered first-line therapy as monotherapy or in combination with surgical excision.³ Other treatment options include intralesional or topical corticosteroids, cyclosporine, 5-fluorouracil, imiquimod, and cryotherapy.^3,6

The development of ICIs has revolutionized the treatment of cutaneous malignancy, yet we have a great deal more to comprehend on the systemic effects of these medications. Although IRAEs may signal a better response to therapy, some of these effects regrettably can be dose limiting. In our patient, cemiplimab was successful in treating locally advanced cSCC, but treatment also resulted in devastating widespread eruptive keratoacanthoma. The mechanism of this kind of eruption has yet to be understood; we hypothesize that it likely involves T lymphocyte–driven inflammation and the interplay of molecular and immune-mediated pathways.

To the Editor:

Treatment of cancer, including cutaneous malignancy, has been transformed by the use of immunotherapeutic agents such as immune checkpoint inhibitors (ICIs) that target cytotoxic T lymphocyte-associated antigen 4, programmed cell-death protein 1 (PD-1), or programmed cell-death ligand 1 (PD-L1). However, these drugs are associated with a distinct set of immune-related adverse events (IRAEs). We present a case of generalized eruptive keratoacanthoma of Grzybowski associated with the ICI cemiplimab.

A 94-year-old White woman presented to the dermatology clinic with acute onset of extensive, locally advanced cutaneous squamous cell carcinoma (cSCC) of the upper right posterolateral calf as well as multiple noninvasive cSCCs of the arms and legs. Her medical history was remarkable for widespread actinic keratoses and numerous cSCCs. The patient had no personal or family history of melanoma. Various cSCCs had required treatment with electrodesiccation and curettage, topical or intralesional 5-fluorouracil, and Mohs micrographic surgery. Approximately 1 year prior to presentation, oral acitretin was initiated to help control the cSCC. Given the extent of locally advanced disease, which was considered unresectable, she was referred to oncology but continued to follow up with dermatology. Positron emission tomography was remarkable for hypermetabolic cutaneous thickening in the upper right posterolateral calf with no evidence of visceral disease.

The patient was started on cemiplimab, an anti-PD-1 monoclonal antibody ICI indicated for the treatment of both metastatic and advanced cSCC. After 4 cycles of intravenous cemiplimab, the patient developed widespread nodules covering the arms and legs (Figure 1) as well as associated tenderness and pruritus. Biopsies of nodules revealed superficially invasive, well-differentiated cSCC consistent with keratoacanthoma. Although a lymphocytic infiltrate was present, no other specific reaction pattern, such as a lichenoid infiltrate, was present (Figure 2).

Positron emission tomography was repeated, demonstrating resolution of the right calf lesion; however, new diffuse cutaneous lesions and inguinal lymph node involvement were present, again without evidence of visceral disease. Given the clinical and histologic findings, a diagnosis of generalized eruptive keratoacanthoma of Grzybowski was made. Cemiplimab was discontinued after the fifth cycle. The patient declined further systemic treatment, instead choosing a regimen of topical steroids and an emollient. 

Immunotherapeutics have transformed cancer therapy, which includes ICIs that target cytotoxic T lymphocyte-associated antigen 4, PD-1, or PD-L1. Increased activity of these checkpoints allows tumor cells to downregulate T-cell activation, thereby evading immune destruction. When PD-1 on T cells binds PD-L1 on tumor cells, T lymphocytes are inhibited from cytotoxic-mediated killing. Therefore, anti-PD-1 ICIs such as cemiplimab permit T-lymphocyte activation and destruction of malignant cells. However, this unique mechanism of immunotherapy is associated with an array of IRAEs, which often manifest in a delayed and prolonged fashion.¹ Immune-related adverse events most commonly affect the gastrointestinal tract as well as the endocrine and dermatologic systems.² Notably, patients with certain tumors who experience these adverse effects might be more likely to have superior overall survival; therefore, IRAEs are sometimes used as an indicator of favorable treatment response.^2,3

Dermatologic IRAEs associated with the use of a PD-1 inhibitor include lichenoid reactions, pruritus, morbilliform eruptions, vitiligo, and bullous pemphigoid.^4,5 Eruptions of keratoacanthoma rarely have been reported following treatment with the PD-1 inhibitors nivolumab and pembrolizumab.^3,6,7 In our patient, we believe the profound and generalized eruptive keratoacanthoma—a well-differentiated cSCC variant—was related to treatment of locally advanced cSCC with cemiplimab. The mechanism underlying the formation of anti-PD-1 eruptive keratoacanthoma is not well understood. In susceptible patients, it is plausible that the inflammatory environment permitted by ICIs paradoxically induces regression of tumors such as locally invasive cSCC and simultaneously promotes formation of keratoacanthoma.

The role of inflammation in the pathogenesis and progression of cSCC is complex and possibly involves contrasting roles of leukocyte subpopulations.⁸ The increased incidence of cSCC in the immunocompromised population,⁸ PD-L1 overexpression in cSCC,^9,10 and successful treatment of cSCC with PD-1 inhibition¹⁰ all suggest that inhibition of specific inflammatory pathways is pivotal in tumor pathogenesis. However, increased inflammation, particularly inflammation driven by T lymphocytes and Langerhans cells, also is believed to play a key role in the formation of cSCCs, including the degeneration of actinic keratosis into cSCC. Moreover, because keratoacanthomas are believed to be a cSCC variant and also are associated with PD-L1 overexpression,⁹ it is perplexing that PD-1 blockade may result in eruptive keratoacanthoma in some patients while also treating locally advanced cSCC, as seen in our patient. Successful treatment of keratoacanthoma with anti-inflammatory intralesional or topical corticosteroids adds to this complicated picture.³

We hypothesize that the pathogenesis of invasive cSCC and keratoacanthoma shares certain immune-mediated mechanisms but also differs in distinct manners. To understand the relationship between systemic treatment of cSCC and eruptive keratoacanthoma, further research is required.

In addition, the RAS/BRAF/MEK oncogenic pathway may be involved in the development of cSCCs associated with anti-PD-1. It is hypothesized that BRAF and MEK inhibition increases T-cell infiltration and increases PD-L1 expression on tumor cells,¹¹ thus increasing the susceptibility of those cells to PD-1 blockade. Further supporting a relationship between the RAS/BRAF/MEK and PD-1 pathways, BRAF inhibitors are associated with development of SCCs and verrucal keratosis by upregulation of the RAS pathway.^12,13 Perhaps a common mechanism underlying these pathways results in their shared association for an increased risk for cSCC upon blockade. More research is needed to fully elucidate the underlying biochemical mechanism of immunotherapy and formation of SCCs, such as keratoacanthoma. 

Treatment of solitary keratoacanthoma often involves surgical excision; however, the sheer number of lesions in eruptive keratoacanthoma presents a larger dilemma. Because oral systemic retinoids have been shown to be most effective for treating eruptive keratoacanthoma, they are considered first-line therapy as monotherapy or in combination with surgical excision.³ Other treatment options include intralesional or topical corticosteroids, cyclosporine, 5-fluorouracil, imiquimod, and cryotherapy.^3,6

The development of ICIs has revolutionized the treatment of cutaneous malignancy, yet we have a great deal more to comprehend on the systemic effects of these medications. Although IRAEs may signal a better response to therapy, some of these effects regrettably can be dose limiting. In our patient, cemiplimab was successful in treating locally advanced cSCC, but treatment also resulted in devastating widespread eruptive keratoacanthoma. The mechanism of this kind of eruption has yet to be understood; we hypothesize that it likely involves T lymphocyte–driven inflammation and the interplay of molecular and immune-mediated pathways.

Nasal tanning spray is a recent phenomenon that has been gaining popularity among consumers on TikTok and other social media platforms. The active ingredient in the tanning spray is melanotan II—a synthetic analog of α‒melanocyte-stimulating hormone,^1,2 a naturally occurring hormone responsible for skin pigmentation. α‒Melanocyte-stimulating hormone is a derivative of the precursor proopiomelanocortin, an agonist on the melanocortin-1 receptor that promotes formation of eumelanin.^1,3 Eumelanin then provides pigmentation to the skin.³ Apart from its use for tanning, melanotan II has been reported to increase sexual function and aid in weight loss.¹

Melanotan II is not approved by the US Food and Drug Administration; however, injectable formulations can be obtained illegally on the Internet as well as at some tanning salons and beauty parlors.⁴ Although injectable forms of melanotan II have been used for years to artificially increase skin pigmentation, the newly hyped nasal tanning sprays are drawing the attention of consumers. The synthetic chemical spray is inhaled into the nasal mucosae, where it is readily absorbed into the bloodstream to act on melanocortin receptors throughout the body, thus enhancing skin pigmentation.² Because melanotan II is not approved, there is no guarantee that the product purchased from those sources is pure; therefore, consumers risk inhaling or injecting contaminated chemicals.⁵

In a 2017 study, Kirk and Greenfield⁶ cited self-image as a common concern among participants who expressed a preference for appearing tanned.⁶ Societal influence and standards to which young adults, particularly young women, often are accustomed drive some to take steps to achieve tanned skin, which they view as more attractive and healthier than untanned skin.^7,8

Social media consumption is a significant risk factor for developing or exacerbating body dissatisfaction among impressionable teenagers and young adults, who may be less risk averse and therefore choose to embrace trends such as nasal tanning sprays to enhance their appearance, without considering possible consequences. Most young adults, and even teens, are aware of the risks associated with tanning beds, which may propel them to seek out what they perceive as a less-risky tanning alternative such as a tanner delivered via a nasal route, but it is unlikely that this group is fully informed about the possible dangers of nasal tanning sprays.

It is crucial for dermatologists and other clinicians to provide awareness and education about the potential harm of nasal tanning sprays. Along with the general risks of using an unregulated substance, common adverse effects include acne, facial flushing, gastrointestinal tract upset, and sensitivity to sunlight (Table).^1,9,10 Several case reports have linked melanotan II to cutaneous changes, including dysplastic nevi and even melanoma.¹ Less common complications, such as renal infarction and priapism, also have been observed with melanotan II use.^9,10

Even with the known risks involving tanning beds and skin cancer, an analysis by Kream et al¹¹ in 2020 showed that 90% (441/488) of tanning-related videos on TikTok promoted a positive view of tanning. Of these TikTok videos involving pro-tanning trends, 3% (12/441) were specifically about melanotan II nasal spray, injection, or both, which has only become more popular since this study was published.¹¹

Dermatologists should be aware of the impact that tanning trends, such as nasal tanning spray, can have on all patients and initiate discussions regarding the risks of using these products with patients as appropriate. Alternatives to nasal tanning sprays such as spray-on tans and self-tanning lotions are safer ways for patients to achieve a tanned look without the health risks associated with melanotan II.

Nasal tanning spray is a recent phenomenon that has been gaining popularity among consumers on TikTok and other social media platforms. The active ingredient in the tanning spray is melanotan II—a synthetic analog of α‒melanocyte-stimulating hormone,^1,2 a naturally occurring hormone responsible for skin pigmentation. α‒Melanocyte-stimulating hormone is a derivative of the precursor proopiomelanocortin, an agonist on the melanocortin-1 receptor that promotes formation of eumelanin.^1,3 Eumelanin then provides pigmentation to the skin.³ Apart from its use for tanning, melanotan II has been reported to increase sexual function and aid in weight loss.¹

Melanotan II is not approved by the US Food and Drug Administration; however, injectable formulations can be obtained illegally on the Internet as well as at some tanning salons and beauty parlors.⁴ Although injectable forms of melanotan II have been used for years to artificially increase skin pigmentation, the newly hyped nasal tanning sprays are drawing the attention of consumers. The synthetic chemical spray is inhaled into the nasal mucosae, where it is readily absorbed into the bloodstream to act on melanocortin receptors throughout the body, thus enhancing skin pigmentation.² Because melanotan II is not approved, there is no guarantee that the product purchased from those sources is pure; therefore, consumers risk inhaling or injecting contaminated chemicals.⁵

In a 2017 study, Kirk and Greenfield⁶ cited self-image as a common concern among participants who expressed a preference for appearing tanned.⁶ Societal influence and standards to which young adults, particularly young women, often are accustomed drive some to take steps to achieve tanned skin, which they view as more attractive and healthier than untanned skin.^7,8

Social media consumption is a significant risk factor for developing or exacerbating body dissatisfaction among impressionable teenagers and young adults, who may be less risk averse and therefore choose to embrace trends such as nasal tanning sprays to enhance their appearance, without considering possible consequences. Most young adults, and even teens, are aware of the risks associated with tanning beds, which may propel them to seek out what they perceive as a less-risky tanning alternative such as a tanner delivered via a nasal route, but it is unlikely that this group is fully informed about the possible dangers of nasal tanning sprays.

It is crucial for dermatologists and other clinicians to provide awareness and education about the potential harm of nasal tanning sprays. Along with the general risks of using an unregulated substance, common adverse effects include acne, facial flushing, gastrointestinal tract upset, and sensitivity to sunlight (Table).^1,9,10 Several case reports have linked melanotan II to cutaneous changes, including dysplastic nevi and even melanoma.¹ Less common complications, such as renal infarction and priapism, also have been observed with melanotan II use.^9,10

Even with the known risks involving tanning beds and skin cancer, an analysis by Kream et al¹¹ in 2020 showed that 90% (441/488) of tanning-related videos on TikTok promoted a positive view of tanning. Of these TikTok videos involving pro-tanning trends, 3% (12/441) were specifically about melanotan II nasal spray, injection, or both, which has only become more popular since this study was published.¹¹

Dermatologists should be aware of the impact that tanning trends, such as nasal tanning spray, can have on all patients and initiate discussions regarding the risks of using these products with patients as appropriate. Alternatives to nasal tanning sprays such as spray-on tans and self-tanning lotions are safer ways for patients to achieve a tanned look without the health risks associated with melanotan II.

Nasal tanning spray is a recent phenomenon that has been gaining popularity among consumers on TikTok and other social media platforms. The active ingredient in the tanning spray is melanotan II—a synthetic analog of α‒melanocyte-stimulating hormone,^1,2 a naturally occurring hormone responsible for skin pigmentation. α‒Melanocyte-stimulating hormone is a derivative of the precursor proopiomelanocortin, an agonist on the melanocortin-1 receptor that promotes formation of eumelanin.^1,3 Eumelanin then provides pigmentation to the skin.³ Apart from its use for tanning, melanotan II has been reported to increase sexual function and aid in weight loss.¹

Melanotan II is not approved by the US Food and Drug Administration; however, injectable formulations can be obtained illegally on the Internet as well as at some tanning salons and beauty parlors.⁴ Although injectable forms of melanotan II have been used for years to artificially increase skin pigmentation, the newly hyped nasal tanning sprays are drawing the attention of consumers. The synthetic chemical spray is inhaled into the nasal mucosae, where it is readily absorbed into the bloodstream to act on melanocortin receptors throughout the body, thus enhancing skin pigmentation.² Because melanotan II is not approved, there is no guarantee that the product purchased from those sources is pure; therefore, consumers risk inhaling or injecting contaminated chemicals.⁵

In a 2017 study, Kirk and Greenfield⁶ cited self-image as a common concern among participants who expressed a preference for appearing tanned.⁶ Societal influence and standards to which young adults, particularly young women, often are accustomed drive some to take steps to achieve tanned skin, which they view as more attractive and healthier than untanned skin.^7,8

Social media consumption is a significant risk factor for developing or exacerbating body dissatisfaction among impressionable teenagers and young adults, who may be less risk averse and therefore choose to embrace trends such as nasal tanning sprays to enhance their appearance, without considering possible consequences. Most young adults, and even teens, are aware of the risks associated with tanning beds, which may propel them to seek out what they perceive as a less-risky tanning alternative such as a tanner delivered via a nasal route, but it is unlikely that this group is fully informed about the possible dangers of nasal tanning sprays.

It is crucial for dermatologists and other clinicians to provide awareness and education about the potential harm of nasal tanning sprays. Along with the general risks of using an unregulated substance, common adverse effects include acne, facial flushing, gastrointestinal tract upset, and sensitivity to sunlight (Table).^1,9,10 Several case reports have linked melanotan II to cutaneous changes, including dysplastic nevi and even melanoma.¹ Less common complications, such as renal infarction and priapism, also have been observed with melanotan II use.^9,10

Even with the known risks involving tanning beds and skin cancer, an analysis by Kream et al¹¹ in 2020 showed that 90% (441/488) of tanning-related videos on TikTok promoted a positive view of tanning. Of these TikTok videos involving pro-tanning trends, 3% (12/441) were specifically about melanotan II nasal spray, injection, or both, which has only become more popular since this study was published.¹¹

Dermatologists should be aware of the impact that tanning trends, such as nasal tanning spray, can have on all patients and initiate discussions regarding the risks of using these products with patients as appropriate. Alternatives to nasal tanning sprays such as spray-on tans and self-tanning lotions are safer ways for patients to achieve a tanned look without the health risks associated with melanotan II.

The Diagnosis: Gnathostomiasis

The biopsy demonstrated a dense, eosinophilic, granulomatous infiltrate surrounding sections of a parasite with skeletal muscle bundles and intestines containing a brush border and luminal debris (Figure), which was consistent with a diagnosis of gnathostomiasis. Upon further questioning, he revealed that while in Peru he frequently consumed ceviche, which is a dish typically made from fresh raw fish cured in lemon or lime juice. He subsequently was treated with oral ivermectin 0.2 mg/kg once daily for 2 days with no evidence of recurrence 12 months later.

Cutaneous gnathostomiasis is the most common manifestation of infection caused by the third-stage larvae of the genus Gnathostoma. The nematode is endemic to tropical and subtropical regions of Japan and Southeast Asia, particularly Thailand. The disease has been increasingly observed in Central and South America. Humans can become infected through ingestion of undercooked meats, particularly freshwater fish but also poultry, snakes, or frogs. Few cases have been reported in North America and Europe presumably due to more stringent regulations governing the sourcing and storage of fish for consumption.^1-3 Restaurants in endemic regions also may use cheaper local freshwater or brackish fish compared to restaurants in the West, which use more expensive saltwater fish that do not harbor Gnathostoma species.¹ There is a false belief among restauranteurs and consumers that the larvae can be reliably killed by marinating meat in citrus juice or with concurrent consumption of alcohol or hot spices.² Adequately cooking or freezing meat to 20 °C for 3 to 5 days are the only effective ways to ensure that the larvae are killed.^1-3

The parasite requires its natural definitive hosts—fish-eating mammals such as pigs, cats, and dogs—to complete its life cycle and reproduce. Humans are accidental hosts in whom the parasite fails to reach sexual maturity.^1-3 Consequently, symptoms commonly are due to the migration of only 1 larva, but occasionally infection with 2 or more has been observed.^1,4

Human infection initially may result in malaise, fever, anorexia, abdominal pain, nausea, vomiting, and diarrhea as the parasite migrates through the stomach, intestines, and liver. After 2 to 4 weeks, larvae may reach the skin where they most commonly create ill-defined, erythematous, indurated, round or oval plaques or nodules described as nodular migratory panniculitis. These lesions tend to develop on the trunk or arms and correspond to the location of the migrating worm.^1,3,5 The larvae have been observed to migrate at 1 cm/h.⁶ Symptoms often wax and wane, with individual nodules lasting approximately 1 to 2 weeks. Uniquely, larval migration can result in a trail of subcutaneous hemorrhage that is considered pathognomonic and helps to differentiate gnathostomiasis from other forms of parasitosis such as strongyloidiasis and sparganosis.^1,3 Larvae are highly motile and invasive, and they are capable of producing a wide range of symptoms affecting virtually any part of the body.^1,2 Depending on the anatomic location of the migrating worm, infection also may result in neurologic, gastrointestinal, pulmonary, or ocular symptoms.^1-3,7 Eosinophilia is common but can subside in the chronic stage, as seen in our patient.¹

The classic triad of intermittent migratory nodules, eosinophilia, and a history of travel to Southeast Asia or another endemic region should raise suspicion for gnathostomiasis.^1-3,5,7 Unfortunately, confirmatory testing such as Gnathostoma serology is not readily available in the United States, and available serologic tests demonstrate frequent false positives and incomplete crossreactivity.^1,2,8 Accordingly, the diagnosis most commonly is solidified by combining cardinal clinical features with histologic findings of a dense eosinophilic inflammatory infiltrate involving the dermis and hypodermis.^2,5 In one study, the larva itself was only found in 12 of 66 (18%) skin biopsy specimens from patients with gnathostomiasis.⁵ If the larva is detected within the sections, it ranges from 2.5 to 12.5 mm in length and 0.4 to 1.2 mm in width and can exhibit cuticular spines, intestinal cells, and characteristic large lateral chords.^1,5

The treatment of choice is surgical removal of the worm. Oral albendazole (400–800 mg/d for 21 days) also is considered a first-line treatment and results in clinical cure in approximately 90% of cases. Two doses of oral ivermectin (0.2 mg/kg) spaced 24 to 48 hours apart is an acceptable alternative with comparable efficacy.^1-3 Care should be taken if involvement of the central nervous system is suspected, as antihelminthic treatment theoretically could be deleterious due to an inflammatory response to the dying larvae.^1,2,9

In the differential diagnosis, loiasis can resemble gnathostomiasis, but the former is endemic to Africa.³ Cutaneous larva migrans most frequently is caused by hookworms from the genus Ancylostoma, which classically leads to superficial serpiginous linear plaques that migrate at a rate of several millimeters per day. However, the larvae are believed to lack the collagenase enzyme required to penetrate the epidermal basement membrane and thus are not capable of producing deep-seated nodules or visceral symptoms.³ Strongyloidiasis (larva currens) generally exhibits a more linear morphology, and infection would result in positive Strongyloides serology.⁷ Erythema nodosum is a septal panniculitis that can be triggered by infection, pregnancy, medications, connective tissue diseases, inflammatory conditions, and underlying malignancy.¹⁰

The Diagnosis: Gnathostomiasis

The biopsy demonstrated a dense, eosinophilic, granulomatous infiltrate surrounding sections of a parasite with skeletal muscle bundles and intestines containing a brush border and luminal debris (Figure), which was consistent with a diagnosis of gnathostomiasis. Upon further questioning, he revealed that while in Peru he frequently consumed ceviche, which is a dish typically made from fresh raw fish cured in lemon or lime juice. He subsequently was treated with oral ivermectin 0.2 mg/kg once daily for 2 days with no evidence of recurrence 12 months later.

Cutaneous gnathostomiasis is the most common manifestation of infection caused by the third-stage larvae of the genus Gnathostoma. The nematode is endemic to tropical and subtropical regions of Japan and Southeast Asia, particularly Thailand. The disease has been increasingly observed in Central and South America. Humans can become infected through ingestion of undercooked meats, particularly freshwater fish but also poultry, snakes, or frogs. Few cases have been reported in North America and Europe presumably due to more stringent regulations governing the sourcing and storage of fish for consumption.^1-3 Restaurants in endemic regions also may use cheaper local freshwater or brackish fish compared to restaurants in the West, which use more expensive saltwater fish that do not harbor Gnathostoma species.¹ There is a false belief among restauranteurs and consumers that the larvae can be reliably killed by marinating meat in citrus juice or with concurrent consumption of alcohol or hot spices.² Adequately cooking or freezing meat to 20 °C for 3 to 5 days are the only effective ways to ensure that the larvae are killed.^1-3

The parasite requires its natural definitive hosts—fish-eating mammals such as pigs, cats, and dogs—to complete its life cycle and reproduce. Humans are accidental hosts in whom the parasite fails to reach sexual maturity.^1-3 Consequently, symptoms commonly are due to the migration of only 1 larva, but occasionally infection with 2 or more has been observed.^1,4

Human infection initially may result in malaise, fever, anorexia, abdominal pain, nausea, vomiting, and diarrhea as the parasite migrates through the stomach, intestines, and liver. After 2 to 4 weeks, larvae may reach the skin where they most commonly create ill-defined, erythematous, indurated, round or oval plaques or nodules described as nodular migratory panniculitis. These lesions tend to develop on the trunk or arms and correspond to the location of the migrating worm.^1,3,5 The larvae have been observed to migrate at 1 cm/h.⁶ Symptoms often wax and wane, with individual nodules lasting approximately 1 to 2 weeks. Uniquely, larval migration can result in a trail of subcutaneous hemorrhage that is considered pathognomonic and helps to differentiate gnathostomiasis from other forms of parasitosis such as strongyloidiasis and sparganosis.^1,3 Larvae are highly motile and invasive, and they are capable of producing a wide range of symptoms affecting virtually any part of the body.^1,2 Depending on the anatomic location of the migrating worm, infection also may result in neurologic, gastrointestinal, pulmonary, or ocular symptoms.^1-3,7 Eosinophilia is common but can subside in the chronic stage, as seen in our patient.¹

The classic triad of intermittent migratory nodules, eosinophilia, and a history of travel to Southeast Asia or another endemic region should raise suspicion for gnathostomiasis.^1-3,5,7 Unfortunately, confirmatory testing such as Gnathostoma serology is not readily available in the United States, and available serologic tests demonstrate frequent false positives and incomplete crossreactivity.^1,2,8 Accordingly, the diagnosis most commonly is solidified by combining cardinal clinical features with histologic findings of a dense eosinophilic inflammatory infiltrate involving the dermis and hypodermis.^2,5 In one study, the larva itself was only found in 12 of 66 (18%) skin biopsy specimens from patients with gnathostomiasis.⁵ If the larva is detected within the sections, it ranges from 2.5 to 12.5 mm in length and 0.4 to 1.2 mm in width and can exhibit cuticular spines, intestinal cells, and characteristic large lateral chords.^1,5

The treatment of choice is surgical removal of the worm. Oral albendazole (400–800 mg/d for 21 days) also is considered a first-line treatment and results in clinical cure in approximately 90% of cases. Two doses of oral ivermectin (0.2 mg/kg) spaced 24 to 48 hours apart is an acceptable alternative with comparable efficacy.^1-3 Care should be taken if involvement of the central nervous system is suspected, as antihelminthic treatment theoretically could be deleterious due to an inflammatory response to the dying larvae.^1,2,9

In the differential diagnosis, loiasis can resemble gnathostomiasis, but the former is endemic to Africa.³ Cutaneous larva migrans most frequently is caused by hookworms from the genus Ancylostoma, which classically leads to superficial serpiginous linear plaques that migrate at a rate of several millimeters per day. However, the larvae are believed to lack the collagenase enzyme required to penetrate the epidermal basement membrane and thus are not capable of producing deep-seated nodules or visceral symptoms.³ Strongyloidiasis (larva currens) generally exhibits a more linear morphology, and infection would result in positive Strongyloides serology.⁷ Erythema nodosum is a septal panniculitis that can be triggered by infection, pregnancy, medications, connective tissue diseases, inflammatory conditions, and underlying malignancy.¹⁰

The Diagnosis: Gnathostomiasis

The biopsy demonstrated a dense, eosinophilic, granulomatous infiltrate surrounding sections of a parasite with skeletal muscle bundles and intestines containing a brush border and luminal debris (Figure), which was consistent with a diagnosis of gnathostomiasis. Upon further questioning, he revealed that while in Peru he frequently consumed ceviche, which is a dish typically made from fresh raw fish cured in lemon or lime juice. He subsequently was treated with oral ivermectin 0.2 mg/kg once daily for 2 days with no evidence of recurrence 12 months later.

Cutaneous gnathostomiasis is the most common manifestation of infection caused by the third-stage larvae of the genus Gnathostoma. The nematode is endemic to tropical and subtropical regions of Japan and Southeast Asia, particularly Thailand. The disease has been increasingly observed in Central and South America. Humans can become infected through ingestion of undercooked meats, particularly freshwater fish but also poultry, snakes, or frogs. Few cases have been reported in North America and Europe presumably due to more stringent regulations governing the sourcing and storage of fish for consumption.^1-3 Restaurants in endemic regions also may use cheaper local freshwater or brackish fish compared to restaurants in the West, which use more expensive saltwater fish that do not harbor Gnathostoma species.¹ There is a false belief among restauranteurs and consumers that the larvae can be reliably killed by marinating meat in citrus juice or with concurrent consumption of alcohol or hot spices.² Adequately cooking or freezing meat to 20 °C for 3 to 5 days are the only effective ways to ensure that the larvae are killed.^1-3

The parasite requires its natural definitive hosts—fish-eating mammals such as pigs, cats, and dogs—to complete its life cycle and reproduce. Humans are accidental hosts in whom the parasite fails to reach sexual maturity.^1-3 Consequently, symptoms commonly are due to the migration of only 1 larva, but occasionally infection with 2 or more has been observed.^1,4

Human infection initially may result in malaise, fever, anorexia, abdominal pain, nausea, vomiting, and diarrhea as the parasite migrates through the stomach, intestines, and liver. After 2 to 4 weeks, larvae may reach the skin where they most commonly create ill-defined, erythematous, indurated, round or oval plaques or nodules described as nodular migratory panniculitis. These lesions tend to develop on the trunk or arms and correspond to the location of the migrating worm.^1,3,5 The larvae have been observed to migrate at 1 cm/h.⁶ Symptoms often wax and wane, with individual nodules lasting approximately 1 to 2 weeks. Uniquely, larval migration can result in a trail of subcutaneous hemorrhage that is considered pathognomonic and helps to differentiate gnathostomiasis from other forms of parasitosis such as strongyloidiasis and sparganosis.^1,3 Larvae are highly motile and invasive, and they are capable of producing a wide range of symptoms affecting virtually any part of the body.^1,2 Depending on the anatomic location of the migrating worm, infection also may result in neurologic, gastrointestinal, pulmonary, or ocular symptoms.^1-3,7 Eosinophilia is common but can subside in the chronic stage, as seen in our patient.¹

The classic triad of intermittent migratory nodules, eosinophilia, and a history of travel to Southeast Asia or another endemic region should raise suspicion for gnathostomiasis.^1-3,5,7 Unfortunately, confirmatory testing such as Gnathostoma serology is not readily available in the United States, and available serologic tests demonstrate frequent false positives and incomplete crossreactivity.^1,2,8 Accordingly, the diagnosis most commonly is solidified by combining cardinal clinical features with histologic findings of a dense eosinophilic inflammatory infiltrate involving the dermis and hypodermis.^2,5 In one study, the larva itself was only found in 12 of 66 (18%) skin biopsy specimens from patients with gnathostomiasis.⁵ If the larva is detected within the sections, it ranges from 2.5 to 12.5 mm in length and 0.4 to 1.2 mm in width and can exhibit cuticular spines, intestinal cells, and characteristic large lateral chords.^1,5

The treatment of choice is surgical removal of the worm. Oral albendazole (400–800 mg/d for 21 days) also is considered a first-line treatment and results in clinical cure in approximately 90% of cases. Two doses of oral ivermectin (0.2 mg/kg) spaced 24 to 48 hours apart is an acceptable alternative with comparable efficacy.^1-3 Care should be taken if involvement of the central nervous system is suspected, as antihelminthic treatment theoretically could be deleterious due to an inflammatory response to the dying larvae.^1,2,9

In the differential diagnosis, loiasis can resemble gnathostomiasis, but the former is endemic to Africa.³ Cutaneous larva migrans most frequently is caused by hookworms from the genus Ancylostoma, which classically leads to superficial serpiginous linear plaques that migrate at a rate of several millimeters per day. However, the larvae are believed to lack the collagenase enzyme required to penetrate the epidermal basement membrane and thus are not capable of producing deep-seated nodules or visceral symptoms.³ Strongyloidiasis (larva currens) generally exhibits a more linear morphology, and infection would result in positive Strongyloides serology.⁷ Erythema nodosum is a septal panniculitis that can be triggered by infection, pregnancy, medications, connective tissue diseases, inflammatory conditions, and underlying malignancy.¹⁰

As medical students, we often assume we are exempt from the diagnoses we learn about. During the first 2 years of medical school, we learn about alopecia as a condition that may be associated with stress, hormonal imbalances, nutrient deficiencies, and aging. However, our curricula do not explore the subtypes, psychosocial impact, or even the overwhelming number of Black women who are disproportionately affected by alopecia. For Black women, hair is a colossal part of their cultural identity, learning from a young age how to nurture and style natural coils. It becomes devastating when women begin to lose them. 

The diagnosis of alopecia subtypes in Black women has been explored in the literature; however, understanding the unique experiences of young Black women is an important part of patient care, as alopecia often is destructive to the patient’s self-image. Therefore, it is important to shed light on these experiences so others feel empowered and supported in their journeys. Herein, we share the experiences of 2 authors (J.D. and C.A.V.O.)—both young Black women—who navigated unexpected hair loss in medical school.

Jewell’s Story

During my first year of medical school, I noticed my hair was shedding more than usual, and my ponytail was not as thick as it once was. I also had an area in my crown that was abnormally thin. My parents suggested that it was a consequence of stress, but I knew something was not right. With only 1 Black dermatologist within 2 hours of Nashville, Tennessee, I remember worrying about seeing a dermatologist who did not understand Black hair. I still scheduled an appointment, but I remember debating if I should straighten my hair or wear my naturally curly Afro. The first dermatologist I saw diagnosed me with seborrheic dermatitis—without even examining my scalp. She told me that I had a “full head of hair” and that I had nothing to worry about. I was unconvinced. Weeks later, I met with another dermatologist who took the time to listen to my concerns. After a scalp biopsy and laboratory work, she diagnosed me with telogen effluvium and androgenetic alopecia. Months later, I had the opportunity to visit the Black dermatologist, and she diagnosed me with central centrifugal cicatricial alopecia. I am grateful for the earlier dermatologists I saw, but I finally feel at ease with my diagnosis and treatment plan after being seen by the latter.

Chidubem’s Story 

From a young age, I was conditioned to think my hair was thick, unmanageable, and a nuisance. I grew accustomed to people yanking on my hair, and my gentle whispers of “this hurts” and “the braid is too tight” being ignored. That continued into adulthood. While studying for the US Medical Licensing Examination, I noticed a burning sensation on my scalp. I decided to ignore it. However, as the days progressed, the slight burning sensation turned into intense burning and itching. I still ignored it. Not only did I lack the funds for a dermatology appointment, but my licensing examination was approaching, and it was more important than anything related to my hair. After the examination, I eventually made an appointment with my primary care physician, who attributed my symptoms to the stressors of medical school. “I think you are having migraines,” she told me. So, I continued to ignore my symptoms. A year passed, and a hair braider pointed out that I had 2 well-defined bald patches on my scalp. I remember feeling angry and confused as to how I missed those findings. I could no longer ignore it—it bothered me less when no one else knew about it. I quickly made a dermatology appointment. Although I opted out of a biopsy, we decided to treat my hair loss empirically, and I have experienced drastic improvement.

Final Thoughts

We are 2 Black women living more than 500 miles away from each other at different medical institutions, yet we share the same experience, which many other women unfortunately face alone. It is not uncommon for us to feel unheard, dismissed, or misdiagnosed. We write this for the Black woman sorting through the feelings of confusion and shock as she traces the hairless spot on her scalp. We write this for the medical student ignoring their symptoms until after their examination. We even write this for any nondermatologists uncomfortable with diagnosing and treating textured hair. To improve patient satisfaction and overall health outcomes, physicians must approach patients with both knowledge and cultural competency. Most importantly, dermatologists (and other physicians) should be appropriately trained in not only the structural differences of textured hair but also the unique practices and beliefs among Black women in relation to their hair.

Acknowledgments—Jewell Dinkins is the inaugural recipient of the Janssen–Skin of Color Research Fellowship at Howard University (Washington, DC), and Chidubem A.V. Okeke is the inaugural recipient of the Women’s Dermatologic Society–La Roche-Posay dermatology fellowship at Howard University.

As medical students, we often assume we are exempt from the diagnoses we learn about. During the first 2 years of medical school, we learn about alopecia as a condition that may be associated with stress, hormonal imbalances, nutrient deficiencies, and aging. However, our curricula do not explore the subtypes, psychosocial impact, or even the overwhelming number of Black women who are disproportionately affected by alopecia. For Black women, hair is a colossal part of their cultural identity, learning from a young age how to nurture and style natural coils. It becomes devastating when women begin to lose them. 

The diagnosis of alopecia subtypes in Black women has been explored in the literature; however, understanding the unique experiences of young Black women is an important part of patient care, as alopecia often is destructive to the patient’s self-image. Therefore, it is important to shed light on these experiences so others feel empowered and supported in their journeys. Herein, we share the experiences of 2 authors (J.D. and C.A.V.O.)—both young Black women—who navigated unexpected hair loss in medical school.

Jewell’s Story

During my first year of medical school, I noticed my hair was shedding more than usual, and my ponytail was not as thick as it once was. I also had an area in my crown that was abnormally thin. My parents suggested that it was a consequence of stress, but I knew something was not right. With only 1 Black dermatologist within 2 hours of Nashville, Tennessee, I remember worrying about seeing a dermatologist who did not understand Black hair. I still scheduled an appointment, but I remember debating if I should straighten my hair or wear my naturally curly Afro. The first dermatologist I saw diagnosed me with seborrheic dermatitis—without even examining my scalp. She told me that I had a “full head of hair” and that I had nothing to worry about. I was unconvinced. Weeks later, I met with another dermatologist who took the time to listen to my concerns. After a scalp biopsy and laboratory work, she diagnosed me with telogen effluvium and androgenetic alopecia. Months later, I had the opportunity to visit the Black dermatologist, and she diagnosed me with central centrifugal cicatricial alopecia. I am grateful for the earlier dermatologists I saw, but I finally feel at ease with my diagnosis and treatment plan after being seen by the latter.

Chidubem’s Story 

From a young age, I was conditioned to think my hair was thick, unmanageable, and a nuisance. I grew accustomed to people yanking on my hair, and my gentle whispers of “this hurts” and “the braid is too tight” being ignored. That continued into adulthood. While studying for the US Medical Licensing Examination, I noticed a burning sensation on my scalp. I decided to ignore it. However, as the days progressed, the slight burning sensation turned into intense burning and itching. I still ignored it. Not only did I lack the funds for a dermatology appointment, but my licensing examination was approaching, and it was more important than anything related to my hair. After the examination, I eventually made an appointment with my primary care physician, who attributed my symptoms to the stressors of medical school. “I think you are having migraines,” she told me. So, I continued to ignore my symptoms. A year passed, and a hair braider pointed out that I had 2 well-defined bald patches on my scalp. I remember feeling angry and confused as to how I missed those findings. I could no longer ignore it—it bothered me less when no one else knew about it. I quickly made a dermatology appointment. Although I opted out of a biopsy, we decided to treat my hair loss empirically, and I have experienced drastic improvement.

Final Thoughts

We are 2 Black women living more than 500 miles away from each other at different medical institutions, yet we share the same experience, which many other women unfortunately face alone. It is not uncommon for us to feel unheard, dismissed, or misdiagnosed. We write this for the Black woman sorting through the feelings of confusion and shock as she traces the hairless spot on her scalp. We write this for the medical student ignoring their symptoms until after their examination. We even write this for any nondermatologists uncomfortable with diagnosing and treating textured hair. To improve patient satisfaction and overall health outcomes, physicians must approach patients with both knowledge and cultural competency. Most importantly, dermatologists (and other physicians) should be appropriately trained in not only the structural differences of textured hair but also the unique practices and beliefs among Black women in relation to their hair.

Acknowledgments—Jewell Dinkins is the inaugural recipient of the Janssen–Skin of Color Research Fellowship at Howard University (Washington, DC), and Chidubem A.V. Okeke is the inaugural recipient of the Women’s Dermatologic Society–La Roche-Posay dermatology fellowship at Howard University.

As medical students, we often assume we are exempt from the diagnoses we learn about. During the first 2 years of medical school, we learn about alopecia as a condition that may be associated with stress, hormonal imbalances, nutrient deficiencies, and aging. However, our curricula do not explore the subtypes, psychosocial impact, or even the overwhelming number of Black women who are disproportionately affected by alopecia. For Black women, hair is a colossal part of their cultural identity, learning from a young age how to nurture and style natural coils. It becomes devastating when women begin to lose them. 

The diagnosis of alopecia subtypes in Black women has been explored in the literature; however, understanding the unique experiences of young Black women is an important part of patient care, as alopecia often is destructive to the patient’s self-image. Therefore, it is important to shed light on these experiences so others feel empowered and supported in their journeys. Herein, we share the experiences of 2 authors (J.D. and C.A.V.O.)—both young Black women—who navigated unexpected hair loss in medical school.

Jewell’s Story

During my first year of medical school, I noticed my hair was shedding more than usual, and my ponytail was not as thick as it once was. I also had an area in my crown that was abnormally thin. My parents suggested that it was a consequence of stress, but I knew something was not right. With only 1 Black dermatologist within 2 hours of Nashville, Tennessee, I remember worrying about seeing a dermatologist who did not understand Black hair. I still scheduled an appointment, but I remember debating if I should straighten my hair or wear my naturally curly Afro. The first dermatologist I saw diagnosed me with seborrheic dermatitis—without even examining my scalp. She told me that I had a “full head of hair” and that I had nothing to worry about. I was unconvinced. Weeks later, I met with another dermatologist who took the time to listen to my concerns. After a scalp biopsy and laboratory work, she diagnosed me with telogen effluvium and androgenetic alopecia. Months later, I had the opportunity to visit the Black dermatologist, and she diagnosed me with central centrifugal cicatricial alopecia. I am grateful for the earlier dermatologists I saw, but I finally feel at ease with my diagnosis and treatment plan after being seen by the latter.

Chidubem’s Story 

From a young age, I was conditioned to think my hair was thick, unmanageable, and a nuisance. I grew accustomed to people yanking on my hair, and my gentle whispers of “this hurts” and “the braid is too tight” being ignored. That continued into adulthood. While studying for the US Medical Licensing Examination, I noticed a burning sensation on my scalp. I decided to ignore it. However, as the days progressed, the slight burning sensation turned into intense burning and itching. I still ignored it. Not only did I lack the funds for a dermatology appointment, but my licensing examination was approaching, and it was more important than anything related to my hair. After the examination, I eventually made an appointment with my primary care physician, who attributed my symptoms to the stressors of medical school. “I think you are having migraines,” she told me. So, I continued to ignore my symptoms. A year passed, and a hair braider pointed out that I had 2 well-defined bald patches on my scalp. I remember feeling angry and confused as to how I missed those findings. I could no longer ignore it—it bothered me less when no one else knew about it. I quickly made a dermatology appointment. Although I opted out of a biopsy, we decided to treat my hair loss empirically, and I have experienced drastic improvement.

Final Thoughts

We are 2 Black women living more than 500 miles away from each other at different medical institutions, yet we share the same experience, which many other women unfortunately face alone. It is not uncommon for us to feel unheard, dismissed, or misdiagnosed. We write this for the Black woman sorting through the feelings of confusion and shock as she traces the hairless spot on her scalp. We write this for the medical student ignoring their symptoms until after their examination. We even write this for any nondermatologists uncomfortable with diagnosing and treating textured hair. To improve patient satisfaction and overall health outcomes, physicians must approach patients with both knowledge and cultural competency. Most importantly, dermatologists (and other physicians) should be appropriately trained in not only the structural differences of textured hair but also the unique practices and beliefs among Black women in relation to their hair.

Acknowledgments—Jewell Dinkins is the inaugural recipient of the Janssen–Skin of Color Research Fellowship at Howard University (Washington, DC), and Chidubem A.V. Okeke is the inaugural recipient of the Women’s Dermatologic Society–La Roche-Posay dermatology fellowship at Howard University.

To the Editor:

Lenalidomide is a thalidomide analogue used to treat various hematologic malignancies, including non-Hodgkin lymphoma, myelodysplastic syndrome, and multiple myeloma (MM).¹ Lenalidomide is referred to as a degrader therapeutic because it induces targeted protein degradation of disease-relevant proteins (eg, Ikaros family zinc finger protein 1 [IKZF1], Ikaros family zinc finger protein 3 [IKZF3], and casein kinase I isoform-α [CK1α]) as its primary mechanism of action.^1,2 Although cutaneous adverse events are relatively common among thalidomide analogues, the morphologic and histopathologic descriptions of these drug eruptions have not been fully elucidated.^3,4 We report a novel pityriasiform drug eruption followed by a clinical eruption suggestive of blaschkitis in a patient with MM who was being treated with lenalidomide.

A 76-year-old man presented to the dermatology clinic with a progressive, mildly pruritic eruption on the chest and axillae of 1 year’s duration. He had a medical history of chronic hepatitis B, malignant carcinoid tumor of the colon, prostate cancer, and MM. The eruption emerged 1 to 2 weeks after the patient started oral lenalidomide 10 mg/d and oral dexamethasone40 mg/wk following autologous stem cell transplantation for MM. The patient had not received any other therapy for MM.

Physical examination revealed multiple erythematous, hyperpigmented, scaly papules and plaques on the lateral chest and within the axillae (Figure 1). A skin biopsy from the left axilla demonstrated a mild lichenoid and perivascular lymphocytic infiltrate with scattered eosinophils, neutrophils, and extravasated erythrocytes. The overlying epidermis showed spongiosis with parakeratosis in addition to lymphocytic exocytosis (Figure 2). No fungal organisms were highlighted on periodic acid–Schiff staining. After this evaluation, we recommended that the patient discontinue lenalidomide and start taking a topical over-the-counter corticosteroid for 2 weeks. Over time, he noted marked improvement in the eruption and associated pruritus.

After a drug holiday of 2 months, the patient resumed a maintenance dosage of oral lenalidomide 10 mg/d. Four or 5 days after restarting lenalidomide, a pruritic eruption appeared that involved the axillae and the left lower abdomen, circling around to the left lower back. The axillary eruption resolved with a topical over-the-counter corticosteroid; the abdominal eruption persisted.

At the 3-month follow-up visit, physical examination revealed erythematous macules and papules that coalesced over a salmon-colored base along the lines of Blaschko extending from the left lower abdominal quadrant, crossing the left flank, and continuing to the left lower back without crossing the midline (Figure 3).

We recommended that the patient continue treatment through this eruption; he was instructed to apply a corticosteroid cream and resume lenalidomide at the maintenance dosage. A month later, he reported that the eruption and associated pruritus resolved with the corticosteroid cream and resumption of the maintenance dose of lenalidomide. The patient noted no further spread of the eruption.

Cutaneous adverse events are common following lenalidomide. In prior trials, the overall incidence of any-grade rash following lenalidomide exposure was 22% to 33%.⁵ A meta-analysis of 10 trials determined the overall incidence of all-grade and high-grade cutaneous adverse events after exposure to lenalidomide was 27.2% and 3.6%, respectively.⁶ Our case represents a pityriasiform eruption due to lenalidomide followed by a secondary eruption suggestive of blaschkitis.

The rash due to lenalidomide has been described as morbilliform, urticarial, dermatitic, acneform, and undefined.⁷ Lenalidomide-induced rash typically develops during the first month of therapy, similar to our patient’s presentation. It has even been observed in the first week of therapy.⁸ Severe reactions such as Stevens-Johnson syndrome and toxic epidermal necrolysis have been reported.^5,6 Risk factors associated with rash secondary to lenalidomide include advanced age (≥70 years), presence of Bence-Jones protein-type MM in urine, and no prior chemotherapy.⁸ Our patient had 2 of these risk factors: advanced age and no prior chemotherapy for MM. The exact pathogenesis by which lenalidomide leads to a pityriasiform eruption, as in our patient, or to a rash in general is unclear. Studies have hypothesized that a lenalidomide-induced rash could be attributable to a delayed hypersensitivity type IV reaction or to a reaction related to the molecular mechanism of action of the drug.⁹

At the molecular level, the antimyeloma effects of lenalidomide include promoting degradation of transcription factors IKZF1 and IKZF3, which subsequently increases production of IL-2.^1,2,9 Recombinant IL-2 has been associated with an increased incidence of rash in other cancers.⁹ Overexpression of programmed death 1(PD-1) and its ligand (PD-L1) has been demonstrated in MM; lenalidomide has been shown to downregulate both PD-1 and PD-L1. Patients receiving PD-1 and PD-L1 inhibitors commonly have developed rash.⁹ However, the association between lenalidomide and its downregulation of PD-1 and PD-L1 leading to rash has not been fully elucidated. Given the multiple malignancies in our patient—MM, prostate cancer, malignant carcinoid tumor—an underlying paraneoplastic phenomenon may be possible. Additionally, because our patient initially received dexamethasone along with lenalidomide, the manifestation of the initial pityriasiform rash may have been less severe due to the steroid use. Although our patient underwent a 2-month drug holiday following the initial pityriasiform eruption, most lenalidomide-induced rashes do not necessitate discontinuation of the drug.^5,7

Our patient’s secondary drug eruption was clinically suggestive of lenalidomide-induced blaschkitis. A report of a German patient with plasmacytoma described a unilateral papular exanthem that developed 4 months after lenalidomide was initiated.¹⁰ The papular exanthem following the lines of Blaschko lines extended from that patient’s posterior left foot to the calf and on to the thigh and flank,¹⁰ which was more extensive than our patient’s eruption. Blaschkitis in this patient resolved with a corticosteroid cream and UV light therapy¹⁰; lenalidomide was not discontinued, similar to our patient.

The pathogenesis of our patient’s secondary eruption that preferentially involved the lines of Blaschko is unclear. After the initial pityriasiform eruption, the secondary eruption was blaschkitis. Distinguishing dermatomes from the lines of Blaschko, which are thought to represent pathways of epidermal cell migration and proliferation during embryologic development, is important. Genodermatoses such as incontinentia pigmenti and hypomelanosis of Ito involve the lines of Blaschko¹¹; other disorders in the differential diagnosis of linear configurations include linear lichen planus, linear cutaneous lupus erythematosus, linear morphea, and lichen striatus.¹¹ Notably, drug-induced blaschkitis is rare.

Cutaneous adverse reactions from thalidomide analogues are relatively common. Our case of lenalidomide-associated blaschkitis that developed following an initial pityriasiform drug eruption in a patient with MM highlights that dermatologists need to collaborate with the oncologist regarding the severity of drug eruptions to determine if the patient should continue treatment through the cutaneous eruptions or discontinue a vital medication.

To the Editor:

Lenalidomide is a thalidomide analogue used to treat various hematologic malignancies, including non-Hodgkin lymphoma, myelodysplastic syndrome, and multiple myeloma (MM).¹ Lenalidomide is referred to as a degrader therapeutic because it induces targeted protein degradation of disease-relevant proteins (eg, Ikaros family zinc finger protein 1 [IKZF1], Ikaros family zinc finger protein 3 [IKZF3], and casein kinase I isoform-α [CK1α]) as its primary mechanism of action.^1,2 Although cutaneous adverse events are relatively common among thalidomide analogues, the morphologic and histopathologic descriptions of these drug eruptions have not been fully elucidated.^3,4 We report a novel pityriasiform drug eruption followed by a clinical eruption suggestive of blaschkitis in a patient with MM who was being treated with lenalidomide.

A 76-year-old man presented to the dermatology clinic with a progressive, mildly pruritic eruption on the chest and axillae of 1 year’s duration. He had a medical history of chronic hepatitis B, malignant carcinoid tumor of the colon, prostate cancer, and MM. The eruption emerged 1 to 2 weeks after the patient started oral lenalidomide 10 mg/d and oral dexamethasone40 mg/wk following autologous stem cell transplantation for MM. The patient had not received any other therapy for MM.

Physical examination revealed multiple erythematous, hyperpigmented, scaly papules and plaques on the lateral chest and within the axillae (Figure 1). A skin biopsy from the left axilla demonstrated a mild lichenoid and perivascular lymphocytic infiltrate with scattered eosinophils, neutrophils, and extravasated erythrocytes. The overlying epidermis showed spongiosis with parakeratosis in addition to lymphocytic exocytosis (Figure 2). No fungal organisms were highlighted on periodic acid–Schiff staining. After this evaluation, we recommended that the patient discontinue lenalidomide and start taking a topical over-the-counter corticosteroid for 2 weeks. Over time, he noted marked improvement in the eruption and associated pruritus.

After a drug holiday of 2 months, the patient resumed a maintenance dosage of oral lenalidomide 10 mg/d. Four or 5 days after restarting lenalidomide, a pruritic eruption appeared that involved the axillae and the left lower abdomen, circling around to the left lower back. The axillary eruption resolved with a topical over-the-counter corticosteroid; the abdominal eruption persisted.

At the 3-month follow-up visit, physical examination revealed erythematous macules and papules that coalesced over a salmon-colored base along the lines of Blaschko extending from the left lower abdominal quadrant, crossing the left flank, and continuing to the left lower back without crossing the midline (Figure 3).

We recommended that the patient continue treatment through this eruption; he was instructed to apply a corticosteroid cream and resume lenalidomide at the maintenance dosage. A month later, he reported that the eruption and associated pruritus resolved with the corticosteroid cream and resumption of the maintenance dose of lenalidomide. The patient noted no further spread of the eruption.

Cutaneous adverse events are common following lenalidomide. In prior trials, the overall incidence of any-grade rash following lenalidomide exposure was 22% to 33%.⁵ A meta-analysis of 10 trials determined the overall incidence of all-grade and high-grade cutaneous adverse events after exposure to lenalidomide was 27.2% and 3.6%, respectively.⁶ Our case represents a pityriasiform eruption due to lenalidomide followed by a secondary eruption suggestive of blaschkitis.

The rash due to lenalidomide has been described as morbilliform, urticarial, dermatitic, acneform, and undefined.⁷ Lenalidomide-induced rash typically develops during the first month of therapy, similar to our patient’s presentation. It has even been observed in the first week of therapy.⁸ Severe reactions such as Stevens-Johnson syndrome and toxic epidermal necrolysis have been reported.^5,6 Risk factors associated with rash secondary to lenalidomide include advanced age (≥70 years), presence of Bence-Jones protein-type MM in urine, and no prior chemotherapy.⁸ Our patient had 2 of these risk factors: advanced age and no prior chemotherapy for MM. The exact pathogenesis by which lenalidomide leads to a pityriasiform eruption, as in our patient, or to a rash in general is unclear. Studies have hypothesized that a lenalidomide-induced rash could be attributable to a delayed hypersensitivity type IV reaction or to a reaction related to the molecular mechanism of action of the drug.⁹

At the molecular level, the antimyeloma effects of lenalidomide include promoting degradation of transcription factors IKZF1 and IKZF3, which subsequently increases production of IL-2.^1,2,9 Recombinant IL-2 has been associated with an increased incidence of rash in other cancers.⁹ Overexpression of programmed death 1(PD-1) and its ligand (PD-L1) has been demonstrated in MM; lenalidomide has been shown to downregulate both PD-1 and PD-L1. Patients receiving PD-1 and PD-L1 inhibitors commonly have developed rash.⁹ However, the association between lenalidomide and its downregulation of PD-1 and PD-L1 leading to rash has not been fully elucidated. Given the multiple malignancies in our patient—MM, prostate cancer, malignant carcinoid tumor—an underlying paraneoplastic phenomenon may be possible. Additionally, because our patient initially received dexamethasone along with lenalidomide, the manifestation of the initial pityriasiform rash may have been less severe due to the steroid use. Although our patient underwent a 2-month drug holiday following the initial pityriasiform eruption, most lenalidomide-induced rashes do not necessitate discontinuation of the drug.^5,7

Our patient’s secondary drug eruption was clinically suggestive of lenalidomide-induced blaschkitis. A report of a German patient with plasmacytoma described a unilateral papular exanthem that developed 4 months after lenalidomide was initiated.¹⁰ The papular exanthem following the lines of Blaschko lines extended from that patient’s posterior left foot to the calf and on to the thigh and flank,¹⁰ which was more extensive than our patient’s eruption. Blaschkitis in this patient resolved with a corticosteroid cream and UV light therapy¹⁰; lenalidomide was not discontinued, similar to our patient.

The pathogenesis of our patient’s secondary eruption that preferentially involved the lines of Blaschko is unclear. After the initial pityriasiform eruption, the secondary eruption was blaschkitis. Distinguishing dermatomes from the lines of Blaschko, which are thought to represent pathways of epidermal cell migration and proliferation during embryologic development, is important. Genodermatoses such as incontinentia pigmenti and hypomelanosis of Ito involve the lines of Blaschko¹¹; other disorders in the differential diagnosis of linear configurations include linear lichen planus, linear cutaneous lupus erythematosus, linear morphea, and lichen striatus.¹¹ Notably, drug-induced blaschkitis is rare.

Cutaneous adverse reactions from thalidomide analogues are relatively common. Our case of lenalidomide-associated blaschkitis that developed following an initial pityriasiform drug eruption in a patient with MM highlights that dermatologists need to collaborate with the oncologist regarding the severity of drug eruptions to determine if the patient should continue treatment through the cutaneous eruptions or discontinue a vital medication.

To the Editor:

Lenalidomide is a thalidomide analogue used to treat various hematologic malignancies, including non-Hodgkin lymphoma, myelodysplastic syndrome, and multiple myeloma (MM).¹ Lenalidomide is referred to as a degrader therapeutic because it induces targeted protein degradation of disease-relevant proteins (eg, Ikaros family zinc finger protein 1 [IKZF1], Ikaros family zinc finger protein 3 [IKZF3], and casein kinase I isoform-α [CK1α]) as its primary mechanism of action.^1,2 Although cutaneous adverse events are relatively common among thalidomide analogues, the morphologic and histopathologic descriptions of these drug eruptions have not been fully elucidated.^3,4 We report a novel pityriasiform drug eruption followed by a clinical eruption suggestive of blaschkitis in a patient with MM who was being treated with lenalidomide.

A 76-year-old man presented to the dermatology clinic with a progressive, mildly pruritic eruption on the chest and axillae of 1 year’s duration. He had a medical history of chronic hepatitis B, malignant carcinoid tumor of the colon, prostate cancer, and MM. The eruption emerged 1 to 2 weeks after the patient started oral lenalidomide 10 mg/d and oral dexamethasone40 mg/wk following autologous stem cell transplantation for MM. The patient had not received any other therapy for MM.

Physical examination revealed multiple erythematous, hyperpigmented, scaly papules and plaques on the lateral chest and within the axillae (Figure 1). A skin biopsy from the left axilla demonstrated a mild lichenoid and perivascular lymphocytic infiltrate with scattered eosinophils, neutrophils, and extravasated erythrocytes. The overlying epidermis showed spongiosis with parakeratosis in addition to lymphocytic exocytosis (Figure 2). No fungal organisms were highlighted on periodic acid–Schiff staining. After this evaluation, we recommended that the patient discontinue lenalidomide and start taking a topical over-the-counter corticosteroid for 2 weeks. Over time, he noted marked improvement in the eruption and associated pruritus.

After a drug holiday of 2 months, the patient resumed a maintenance dosage of oral lenalidomide 10 mg/d. Four or 5 days after restarting lenalidomide, a pruritic eruption appeared that involved the axillae and the left lower abdomen, circling around to the left lower back. The axillary eruption resolved with a topical over-the-counter corticosteroid; the abdominal eruption persisted.

At the 3-month follow-up visit, physical examination revealed erythematous macules and papules that coalesced over a salmon-colored base along the lines of Blaschko extending from the left lower abdominal quadrant, crossing the left flank, and continuing to the left lower back without crossing the midline (Figure 3).

We recommended that the patient continue treatment through this eruption; he was instructed to apply a corticosteroid cream and resume lenalidomide at the maintenance dosage. A month later, he reported that the eruption and associated pruritus resolved with the corticosteroid cream and resumption of the maintenance dose of lenalidomide. The patient noted no further spread of the eruption.

Cutaneous adverse events are common following lenalidomide. In prior trials, the overall incidence of any-grade rash following lenalidomide exposure was 22% to 33%.⁵ A meta-analysis of 10 trials determined the overall incidence of all-grade and high-grade cutaneous adverse events after exposure to lenalidomide was 27.2% and 3.6%, respectively.⁶ Our case represents a pityriasiform eruption due to lenalidomide followed by a secondary eruption suggestive of blaschkitis.

The rash due to lenalidomide has been described as morbilliform, urticarial, dermatitic, acneform, and undefined.⁷ Lenalidomide-induced rash typically develops during the first month of therapy, similar to our patient’s presentation. It has even been observed in the first week of therapy.⁸ Severe reactions such as Stevens-Johnson syndrome and toxic epidermal necrolysis have been reported.^5,6 Risk factors associated with rash secondary to lenalidomide include advanced age (≥70 years), presence of Bence-Jones protein-type MM in urine, and no prior chemotherapy.⁸ Our patient had 2 of these risk factors: advanced age and no prior chemotherapy for MM. The exact pathogenesis by which lenalidomide leads to a pityriasiform eruption, as in our patient, or to a rash in general is unclear. Studies have hypothesized that a lenalidomide-induced rash could be attributable to a delayed hypersensitivity type IV reaction or to a reaction related to the molecular mechanism of action of the drug.⁹

At the molecular level, the antimyeloma effects of lenalidomide include promoting degradation of transcription factors IKZF1 and IKZF3, which subsequently increases production of IL-2.^1,2,9 Recombinant IL-2 has been associated with an increased incidence of rash in other cancers.⁹ Overexpression of programmed death 1(PD-1) and its ligand (PD-L1) has been demonstrated in MM; lenalidomide has been shown to downregulate both PD-1 and PD-L1. Patients receiving PD-1 and PD-L1 inhibitors commonly have developed rash.⁹ However, the association between lenalidomide and its downregulation of PD-1 and PD-L1 leading to rash has not been fully elucidated. Given the multiple malignancies in our patient—MM, prostate cancer, malignant carcinoid tumor—an underlying paraneoplastic phenomenon may be possible. Additionally, because our patient initially received dexamethasone along with lenalidomide, the manifestation of the initial pityriasiform rash may have been less severe due to the steroid use. Although our patient underwent a 2-month drug holiday following the initial pityriasiform eruption, most lenalidomide-induced rashes do not necessitate discontinuation of the drug.^5,7

Our patient’s secondary drug eruption was clinically suggestive of lenalidomide-induced blaschkitis. A report of a German patient with plasmacytoma described a unilateral papular exanthem that developed 4 months after lenalidomide was initiated.¹⁰ The papular exanthem following the lines of Blaschko lines extended from that patient’s posterior left foot to the calf and on to the thigh and flank,¹⁰ which was more extensive than our patient’s eruption. Blaschkitis in this patient resolved with a corticosteroid cream and UV light therapy¹⁰; lenalidomide was not discontinued, similar to our patient.

The pathogenesis of our patient’s secondary eruption that preferentially involved the lines of Blaschko is unclear. After the initial pityriasiform eruption, the secondary eruption was blaschkitis. Distinguishing dermatomes from the lines of Blaschko, which are thought to represent pathways of epidermal cell migration and proliferation during embryologic development, is important. Genodermatoses such as incontinentia pigmenti and hypomelanosis of Ito involve the lines of Blaschko¹¹; other disorders in the differential diagnosis of linear configurations include linear lichen planus, linear cutaneous lupus erythematosus, linear morphea, and lichen striatus.¹¹ Notably, drug-induced blaschkitis is rare.

Cutaneous adverse reactions from thalidomide analogues are relatively common. Our case of lenalidomide-associated blaschkitis that developed following an initial pityriasiform drug eruption in a patient with MM highlights that dermatologists need to collaborate with the oncologist regarding the severity of drug eruptions to determine if the patient should continue treatment through the cutaneous eruptions or discontinue a vital medication.