Mixed Topics

Steatocystomas are small sebum-filled cysts that typically manifest in the dermis and originate from sebaceous follicles. Although commonly asymptomatic, these lesions can manifest with pruritus or become infected, predisposing patients to further complications.¹ Steatocystomas can manifest as single (steatocystoma simplex [SS]) or numerous (steatocystoma multiplex [SM]) lesions; the lesions also can spontaneously rupture with characteristics that resemble hidradenitis suppurativa (HS)(steatocystoma multiplex suppurativa [SMS]).^1,2

Steatocystomas are relatively rare, and there is limited consensus in the published literature on the etiology and management of this condition. In this article, we present a comprehensive review of steatocystomas in the current literature. We highlight important features to consider when making the diagnosis and also offer recommendations for best-practice treatment.

Historical Background

Although not explicitly identified by name, the first documentation of steatocystomas is a case report published in 1873. In this account, the author described a patient who presented with approximately 250 flesh-colored dermal cysts across the body that varied in size.³ In 1899, the term steatocystoma multiple—derived from Greek roots meaning “fatty bag”—was first used.⁴

In 1982, almost a century later, Brownstein⁵ reported some of the earliest cases of SS. This solitary subtype is identical to SM on a microscopic level; however, unlike SM, this variant occurs as a single lesion that typically forms in adulthood and in the absence of family history. Other benign adnexal tumors (eg, pilomatricomas, pilar cysts, and sebaceous hyperplasias) also can manifest as either solitary or multiple lesions.

In 1976, McDonald and Reed⁶ reported the first known cases of patients with both SM and HS. At the time, the co-occurrence of these conditions was viewed as coincidental, but there were postulations of a shared inflammatory process and hereditary link⁶; it was not until 1982 that the term steatocystoma multiplex suppurativum was coined to describe this variant.⁷ Although rare, there have been multiple documented instances of SMS since. It has been suggested that the convergence of these conditions may indicate a shared follicular proliferation defect.⁸ Ongoing investigation is warranted to explain the underlying pathogenesis of this unique variant.

Epidemiology

The available epidemiologic data primarily relate to SM, the most common steatocystoma variant. Nevertheless, SM is a relatively rare condition, and the exact incidence and prevalence remain unknown.^8,9 Steatocystomas typically manifest in the first and second decades of life and have been observed in patients of both sexes, with studies demonstrating no notable sex bias.^4,9

Etiology and Pathophysiology

Steatocystomas can occur sporadically or may be inherited as an autosomal-dominant condition.⁴ Typically, SS tends to manifest as an isolated occurrence without any inherent genetic predisposition.⁵ Alternatively, SM may develop sporadically or be associated with a mutation in the keratin 17 gene (KRT17).⁴ Steatocystoma multiplex also has been associated with at least 4 different missense mutations, including N92H, R94H, and R94C, located on the long (q) arm of chromosome 17.^4,10-12

The keratin 17 gene is responsible for encoding the keratin 17 protein, a type I intermediate filament predominantly synthesized in the basal cells of epithelial tissue. This fibrous structural protein can regulate many processes, including inflammation and cell proliferation, and is found in regions such as the sebaceous glands, hair follicles, and eccrine sweat glands. Overexpression of KRT17 has been suggested in other cutaneous conditions, most notably psoriasis.¹² Despite KRT17’s many roles, it remains unclear why SM typically manifests with a myriad of sebum-containing cysts as the primary symptom.¹² Continued investigation into the genetic underpinnings of SM and the keratin 17 protein is necessary to further elucidate a more comprehensive understanding of this condition.

Hormonal influences have been suggested as a potential trigger for steatocystoma growth.^4,13 This condition is associated with dysfunction of the sebaceous glands, and, correspondingly, the incidence of disease is highest in pubertal patients, in whom androgen levels and sebum production are elevated.^4,13,14 Two cases of transgender men taking testosterone therapy presenting with steatocystomas provide additional clinical support for this association.¹⁵

Additionally, the use of immunomodulatory agents, such as ustekinumab (anti–interleukin 12/interleukin 23), has been shown to trigger SM. It is predicted that the reduced expression of certain interferons and interleukins may lead to downstream consequences in the keratin 17 pathway and lead to SM lesion formation in genetically susceptible individuals.¹⁶ Targeting these potential causes in the future may prove efficacious in the secondary prevention of familial SM manifestation or exacerbations.

Mutations in the KRT17 gene also have been implicated in pachyonychia congenita type 2 (PC-2).⁴ Marked by extensive systemic hyperkeratosis, PC-2 has been observed to coincide with SM in certain patients.^4,5 Interestingly, the location of the KRT17 mutations are identical in both PC-2 and SM.⁴ Although most individuals with hereditary SM do not exhibit the characteristic features of PC-2, mild nail and dental abnormalities have been observed in some SM cases.^4,10 This relationship suggests that SM may be a less severe variant of PC-2 or part of a complex polygenetic spectrum of disease.¹⁰ Further research is imperative to determine the exact nature and extent of the relationship between these conditions.

Clinical Manifestations

Steatocystomas are flesh-colored subcutaneous cysts that range in size from less than 3 mm to larger than 3 cm in diameter (Figure). They form within a single pilosebaceous unit and typically display firm attachment due to their origination in the dermis.^2,7,17 Steatocystomas generally contain lipid material, and less frequently, keratin and hair shafts, distinguishing them as the only “true” sebaceous cysts.¹⁸ Their color can range from flesh-toned to yellow, with reports of occasional dark-blue shades and calcifications.^19,20 Steatocystomas can persist indefinitely, and they usually are asymptomatic.

Diagnosis of steatocystoma is confirmed by biopsy.⁴ Steatocystomas are characterized by a dermal cyst lined by stratified squamous cell epithelium (eFigures 1 and 2).²¹ Classically they feature flattened sebaceous lobules, multinucleated giant cells, and abortive hair follicles. The lining of these cysts is marked by lymphocytic infiltrate and a dense, wrinkled, eosinophilic keratin cuticle that replaces the granular layer.²² The cyst maintains an epidermal connection through a follicular infundibulum characterized by clumps of keratinocytes, sebocytes, corneocytes, and/or hair follicles.⁷ Aspirated contents reveal crystalline structures and anucleate squamous cells upon microscopic analysis. That being said, variable histologic findings of steatocystomas have been described.²³

Steatocystoma simplex, as the name implies, classifies a single isolated steatocystoma. This subtype exhibits similar histopathologic and clinical features to the other subtypes of steatocystomas. Notably, SS is not associated with a genetic mutation and is not an inherited condition within families.⁵ Steatocystoma multiplex manifests with many steatocystomas, often distributed widely across the body.^3,4 The chest, axillae, and groin are the most common locations; however, these cysts can manifest on the face, back, abdomen, and extremities.^4,18-22 Rare occurrences of SM limited to the face, scalp, and distal extremities have been documented.^18,21,24,25 Due to the possibility of an autosomal-dominant inheritance, it is advisable to take a comprehensive family history in patients for whom SM is in the differential.¹⁷

Steatocystoma multiplex—especially familial variants—has been shown to develop in conjunction with other dermatologic conditions, including eruptive vellus hair (EVH) cysts, persistent infantile milia, and epidermoid/dermoid cysts.²⁶ While some investigators regard these as separate entities due to their varied genetic etiology, it has been suggested that these conditions may be related and that the diagnosis is determined by the location of cyst origin along the sebaceous ducts.^26,27 Other dermatologic conditions and lesions that frequently manifest comorbidly with SM include hidrocystomas, syringomas, pilonidal cysts, lichen planus, nodulocystic acne, trichotillomania, trichoblastomas, trichoepithelioma, HS, keratoacanthomas, acrokeratosis verruciformis of Hopf, and embryonal hair formation. Steatocystoma multiplex, manifesting comorbidly with dental and orofacial malformations (eg, partial noneruption of secondary teeth, natal and defective teeth, and bilateral preauricular sinuses) has been classified as SM natal teeth syndrome.⁶

Steatocystoma multiplex suppurativa is a rare and serious variant of SM characterized by inflammation, cyst rupture, sinus tract formation, and scarring.²⁴ Patients with SMS typically have multiple intact SM cysts, which can aid in differentiation from HS.^2,24 Steatocystoma multiplex suppurativa is associated with more complications than SS and SM, including cyst perforation, development of purulent and/or foul-smelling discharge, infection, scarring, pain, and overall discomfort.²

Given its rarity and the potential manifestations that overlap with other conditions, steatocystomas easily can be misdiagnosed. In some clinical instances, EVHs may share similar characteristics with SM; however, certain distinguishing features exist, including a central tuft of protruding hairs and different expressed contents, such as the vellus hair shafts, from the cyst’s lumen.²⁸ Furthermore, histologic examination of EVHs reveals epidermoid keratinization of the lining as well as a lack of sebaceous glands within the wall.^28,29 Other similar conditions include epidermoid cysts, pilar cysts, lipomas, epidermal inclusion cysts, dermoid cysts, sebaceous hyperplasia, folliculitis, xanthomas, neurofibromatosis, and syringomas.³⁰ Occasionally, SMS can be mistaken for HS or acne conglobata, and SM lesions with a facial distribution can mimic acne vulgaris.^1,31 These conditions should be excluded before a diagnosis of SS, SM, or SMS is made. 

Importantly, SM is visually indistinguishable from subcutaneous metastasis on physical examination, and there are reports of oncologic conditions (eg, pulmonary adenocarcinoma metastasized to the skin) being mistaken for SS or SM.³² Therefore, a thorough clinical examination, histopathologic analysis, and potential use of other imaging modalities such as ultrasonography (US) are needed to ensure an accurate diagnosis.

Ultrasonography has demonstrated utility in diagnosing steatocystomas.^33-35 Steatocystomas have incidentally been found on routine mammograms and can demonstrate well-defined circular nodules with radiolucent characteristics and a thin radiodense outline.^33,36 Homogeneous hypoechoic nodules within the dermis without posterior acoustic features generally are observed (eFigure 3).^33,37 In patients declining biopsy, US may be useful in further characterization of an unknown lesion. Color Doppler US can be used to distinguish SMS from HS. Specifically, SM typically exhibits an absence of Doppler signaling due to a lack of vascularity, providing a helpful diagnostic clue for the SMS variant.³³

Management and Treatment Options

There is no established standard treatment for steatocystomas; therefore, the approach to management is contingent on clinical presentation and patient preferences. Various medical, surgical, and laser management options are available, each with its own advantages and limitations. Treatment of SM is difficult due to the large number of lesions.³⁸ In many cases, continued observation is a viable treatment option, as most SS and SM lesions are asymptomatic; however, cosmetic concerns can be debilitating for patients with SM and may warrant intervention.³⁹ More extensive medical and surgical management often are necessary in SMS due to associated morbidity. Discussing options and goals as well as setting realistic expectations with the patient are essential in determining the optimal approach.

Medical Management—In medical literature, oral isotretinoin (13-cis-retinoic acid) has been the mainstay of therapy for steatocystoma, as its effect on the size and activity of sebaceous glands is hypothesized to decrease disease activity.^38,40 Interventional studies and case reports have exhibited varying degrees of effectiveness.^1,38-41 Some reports depict a reduction in the formation of new lesions and a decrease in the size of pre-existing lesions, some show mild delayed therapeutic efficacy, and others suggest exacerbation of the condition.^1,38-41 This outcome variability is attributed to isotretinoin’s preferential efficacy in treating inflammatory lesions.^40,42

Tetracycline derivatives and intralesional steroid injections also have been employed with some efficacy in patients with focal inflammatory SM and SMS.⁴³ There is limited evidence on the long-term outcomes of these interventions, and intralesional injections often are not recommended in conditions such as SM, in which there are many lesions present.

Surgical Management—Minimally invasive surgical procedures including drainage and resections have been used with varying efficacy in SS and SM. Typically, a 2- to 3-mm incision or sharp-tipped cautery is employed to puncture the cyst. Alternatively, radiofrequency probes with a 2.4-MHz frequency setting have been used to minimize incision size.⁴⁴ The contents then are expressed with manual pressure or forceps, and the cyst sac is extracted using forceps and/or a vein hook (eFigure 4).^44,45 The specific surgical techniques and their respective advantages and limitations are summarized in the eTable. Reported advantages and limitations of surgical techniques are derived from information provided by the authors of steatocystoma case reports, which are based on observations of a very limited sample size.

Laser Treatment—Various laser modalities have been used in the management of steatocystomas, including carbon dioxide lasers, erbium-doped yttrium aluminum garnet lasers, 1450-nm diode plus 1550-nm fractionated erbium-doped fiber lasers, and 1927-nm diode lasers.^54,55-57 These lasers are used to perforate the cyst before extirpation and have displayed advantages in minimizing scar length.⁵⁸ The super-pulse mode of carbon dioxide lasers demonstrates efficacy with minimal scarring and recurrence, and this mode is preferred to minimize thermal damage.^54,59 Furthermore, this modality can be especially useful in patients whose condition is refractory to other noninvasive options.⁵⁹ Similarly, the erbium-doped yttrium aluminum garnet laser was well tolerated with no complications noted.⁵⁵ The 1927-nm diode laser also displayed good outcomes as well as no recurrence.⁵⁷ With laser use, it is important to note that multiple treatments are needed to see optimal outcomes.⁵⁴ Moreover, laser settings must be carefully considered, especially in patients with Fitzpatrick skin type III or higher, and topical anti-inflammatory agents should be considered posttreatment to minimize complications.^54,59,60

Recommendations

For management of SS, we recommend conservative therapy of watchful observation, as scarring or postinflammatory pigment change may be brought on by medical or surgical therapy; however, if SS is cosmetically bothersome, laser or surgical excision can be done (eFigure 4).^4,43-53 It is important to counsel the patient on risks/benefits. For SM, watchful observation also is indicated; however, systemic therapies aimed at prevention may be the most efficacious by limiting disease progression, and oral tetracycline or isotretinoin may be tried.⁴ Tetracyclines have the risk for photosensitivity and are teratogenic, while isotretinoin is extremely teratogenic, requires laboratory monitoring and regular pregnancy tests in women, and often causes substantial mucosal dryness. If lesions are bothersome or refractory to these therapies, intralesional steroids or surgical/laser procedures can be tried throughout multiple visits.^43-53 For SMS, systemic therapies frequently are recommended. The risks of systemic tetracycline and isotretinoin therapies must be discussed. Patients with treatment-refractory SMS may require surgical excision or deroofing of sinus tracts.^43-53 This management is similar to that of HS and must be tailored to the patient.

Conclusion

Overall, steatocystomas are a relatively rare pathology, with a limited consensus on their etiology and management. This review summarizes the current knowledge on the condition to support clinicians in diagnosis and management, ranging from watchful waiting to surgical removal. By individualizing treatment plans, clinicians ultimately can optimize outcomes in patients with steatocystomas.

Steatocystomas are small sebum-filled cysts that typically manifest in the dermis and originate from sebaceous follicles. Although commonly asymptomatic, these lesions can manifest with pruritus or become infected, predisposing patients to further complications.¹ Steatocystomas can manifest as single (steatocystoma simplex [SS]) or numerous (steatocystoma multiplex [SM]) lesions; the lesions also can spontaneously rupture with characteristics that resemble hidradenitis suppurativa (HS)(steatocystoma multiplex suppurativa [SMS]).^1,2

Steatocystomas are relatively rare, and there is limited consensus in the published literature on the etiology and management of this condition. In this article, we present a comprehensive review of steatocystomas in the current literature. We highlight important features to consider when making the diagnosis and also offer recommendations for best-practice treatment.

Historical Background

Although not explicitly identified by name, the first documentation of steatocystomas is a case report published in 1873. In this account, the author described a patient who presented with approximately 250 flesh-colored dermal cysts across the body that varied in size.³ In 1899, the term steatocystoma multiple—derived from Greek roots meaning “fatty bag”—was first used.⁴

In 1982, almost a century later, Brownstein⁵ reported some of the earliest cases of SS. This solitary subtype is identical to SM on a microscopic level; however, unlike SM, this variant occurs as a single lesion that typically forms in adulthood and in the absence of family history. Other benign adnexal tumors (eg, pilomatricomas, pilar cysts, and sebaceous hyperplasias) also can manifest as either solitary or multiple lesions.

In 1976, McDonald and Reed⁶ reported the first known cases of patients with both SM and HS. At the time, the co-occurrence of these conditions was viewed as coincidental, but there were postulations of a shared inflammatory process and hereditary link⁶; it was not until 1982 that the term steatocystoma multiplex suppurativum was coined to describe this variant.⁷ Although rare, there have been multiple documented instances of SMS since. It has been suggested that the convergence of these conditions may indicate a shared follicular proliferation defect.⁸ Ongoing investigation is warranted to explain the underlying pathogenesis of this unique variant.

Epidemiology

The available epidemiologic data primarily relate to SM, the most common steatocystoma variant. Nevertheless, SM is a relatively rare condition, and the exact incidence and prevalence remain unknown.^8,9 Steatocystomas typically manifest in the first and second decades of life and have been observed in patients of both sexes, with studies demonstrating no notable sex bias.^4,9

Etiology and Pathophysiology

Steatocystomas can occur sporadically or may be inherited as an autosomal-dominant condition.⁴ Typically, SS tends to manifest as an isolated occurrence without any inherent genetic predisposition.⁵ Alternatively, SM may develop sporadically or be associated with a mutation in the keratin 17 gene (KRT17).⁴ Steatocystoma multiplex also has been associated with at least 4 different missense mutations, including N92H, R94H, and R94C, located on the long (q) arm of chromosome 17.^4,10-12

The keratin 17 gene is responsible for encoding the keratin 17 protein, a type I intermediate filament predominantly synthesized in the basal cells of epithelial tissue. This fibrous structural protein can regulate many processes, including inflammation and cell proliferation, and is found in regions such as the sebaceous glands, hair follicles, and eccrine sweat glands. Overexpression of KRT17 has been suggested in other cutaneous conditions, most notably psoriasis.¹² Despite KRT17’s many roles, it remains unclear why SM typically manifests with a myriad of sebum-containing cysts as the primary symptom.¹² Continued investigation into the genetic underpinnings of SM and the keratin 17 protein is necessary to further elucidate a more comprehensive understanding of this condition.

Hormonal influences have been suggested as a potential trigger for steatocystoma growth.^4,13 This condition is associated with dysfunction of the sebaceous glands, and, correspondingly, the incidence of disease is highest in pubertal patients, in whom androgen levels and sebum production are elevated.^4,13,14 Two cases of transgender men taking testosterone therapy presenting with steatocystomas provide additional clinical support for this association.¹⁵

Additionally, the use of immunomodulatory agents, such as ustekinumab (anti–interleukin 12/interleukin 23), has been shown to trigger SM. It is predicted that the reduced expression of certain interferons and interleukins may lead to downstream consequences in the keratin 17 pathway and lead to SM lesion formation in genetically susceptible individuals.¹⁶ Targeting these potential causes in the future may prove efficacious in the secondary prevention of familial SM manifestation or exacerbations.

Mutations in the KRT17 gene also have been implicated in pachyonychia congenita type 2 (PC-2).⁴ Marked by extensive systemic hyperkeratosis, PC-2 has been observed to coincide with SM in certain patients.^4,5 Interestingly, the location of the KRT17 mutations are identical in both PC-2 and SM.⁴ Although most individuals with hereditary SM do not exhibit the characteristic features of PC-2, mild nail and dental abnormalities have been observed in some SM cases.^4,10 This relationship suggests that SM may be a less severe variant of PC-2 or part of a complex polygenetic spectrum of disease.¹⁰ Further research is imperative to determine the exact nature and extent of the relationship between these conditions.

Clinical Manifestations

Steatocystomas are flesh-colored subcutaneous cysts that range in size from less than 3 mm to larger than 3 cm in diameter (Figure). They form within a single pilosebaceous unit and typically display firm attachment due to their origination in the dermis.^2,7,17 Steatocystomas generally contain lipid material, and less frequently, keratin and hair shafts, distinguishing them as the only “true” sebaceous cysts.¹⁸ Their color can range from flesh-toned to yellow, with reports of occasional dark-blue shades and calcifications.^19,20 Steatocystomas can persist indefinitely, and they usually are asymptomatic.

Diagnosis of steatocystoma is confirmed by biopsy.⁴ Steatocystomas are characterized by a dermal cyst lined by stratified squamous cell epithelium (eFigures 1 and 2).²¹ Classically they feature flattened sebaceous lobules, multinucleated giant cells, and abortive hair follicles. The lining of these cysts is marked by lymphocytic infiltrate and a dense, wrinkled, eosinophilic keratin cuticle that replaces the granular layer.²² The cyst maintains an epidermal connection through a follicular infundibulum characterized by clumps of keratinocytes, sebocytes, corneocytes, and/or hair follicles.⁷ Aspirated contents reveal crystalline structures and anucleate squamous cells upon microscopic analysis. That being said, variable histologic findings of steatocystomas have been described.²³

Steatocystoma simplex, as the name implies, classifies a single isolated steatocystoma. This subtype exhibits similar histopathologic and clinical features to the other subtypes of steatocystomas. Notably, SS is not associated with a genetic mutation and is not an inherited condition within families.⁵ Steatocystoma multiplex manifests with many steatocystomas, often distributed widely across the body.^3,4 The chest, axillae, and groin are the most common locations; however, these cysts can manifest on the face, back, abdomen, and extremities.^4,18-22 Rare occurrences of SM limited to the face, scalp, and distal extremities have been documented.^18,21,24,25 Due to the possibility of an autosomal-dominant inheritance, it is advisable to take a comprehensive family history in patients for whom SM is in the differential.¹⁷

Steatocystoma multiplex—especially familial variants—has been shown to develop in conjunction with other dermatologic conditions, including eruptive vellus hair (EVH) cysts, persistent infantile milia, and epidermoid/dermoid cysts.²⁶ While some investigators regard these as separate entities due to their varied genetic etiology, it has been suggested that these conditions may be related and that the diagnosis is determined by the location of cyst origin along the sebaceous ducts.^26,27 Other dermatologic conditions and lesions that frequently manifest comorbidly with SM include hidrocystomas, syringomas, pilonidal cysts, lichen planus, nodulocystic acne, trichotillomania, trichoblastomas, trichoepithelioma, HS, keratoacanthomas, acrokeratosis verruciformis of Hopf, and embryonal hair formation. Steatocystoma multiplex, manifesting comorbidly with dental and orofacial malformations (eg, partial noneruption of secondary teeth, natal and defective teeth, and bilateral preauricular sinuses) has been classified as SM natal teeth syndrome.⁶

Steatocystoma multiplex suppurativa is a rare and serious variant of SM characterized by inflammation, cyst rupture, sinus tract formation, and scarring.²⁴ Patients with SMS typically have multiple intact SM cysts, which can aid in differentiation from HS.^2,24 Steatocystoma multiplex suppurativa is associated with more complications than SS and SM, including cyst perforation, development of purulent and/or foul-smelling discharge, infection, scarring, pain, and overall discomfort.²

Given its rarity and the potential manifestations that overlap with other conditions, steatocystomas easily can be misdiagnosed. In some clinical instances, EVHs may share similar characteristics with SM; however, certain distinguishing features exist, including a central tuft of protruding hairs and different expressed contents, such as the vellus hair shafts, from the cyst’s lumen.²⁸ Furthermore, histologic examination of EVHs reveals epidermoid keratinization of the lining as well as a lack of sebaceous glands within the wall.^28,29 Other similar conditions include epidermoid cysts, pilar cysts, lipomas, epidermal inclusion cysts, dermoid cysts, sebaceous hyperplasia, folliculitis, xanthomas, neurofibromatosis, and syringomas.³⁰ Occasionally, SMS can be mistaken for HS or acne conglobata, and SM lesions with a facial distribution can mimic acne vulgaris.^1,31 These conditions should be excluded before a diagnosis of SS, SM, or SMS is made. 

Importantly, SM is visually indistinguishable from subcutaneous metastasis on physical examination, and there are reports of oncologic conditions (eg, pulmonary adenocarcinoma metastasized to the skin) being mistaken for SS or SM.³² Therefore, a thorough clinical examination, histopathologic analysis, and potential use of other imaging modalities such as ultrasonography (US) are needed to ensure an accurate diagnosis.

Ultrasonography has demonstrated utility in diagnosing steatocystomas.^33-35 Steatocystomas have incidentally been found on routine mammograms and can demonstrate well-defined circular nodules with radiolucent characteristics and a thin radiodense outline.^33,36 Homogeneous hypoechoic nodules within the dermis without posterior acoustic features generally are observed (eFigure 3).^33,37 In patients declining biopsy, US may be useful in further characterization of an unknown lesion. Color Doppler US can be used to distinguish SMS from HS. Specifically, SM typically exhibits an absence of Doppler signaling due to a lack of vascularity, providing a helpful diagnostic clue for the SMS variant.³³

Management and Treatment Options

There is no established standard treatment for steatocystomas; therefore, the approach to management is contingent on clinical presentation and patient preferences. Various medical, surgical, and laser management options are available, each with its own advantages and limitations. Treatment of SM is difficult due to the large number of lesions.³⁸ In many cases, continued observation is a viable treatment option, as most SS and SM lesions are asymptomatic; however, cosmetic concerns can be debilitating for patients with SM and may warrant intervention.³⁹ More extensive medical and surgical management often are necessary in SMS due to associated morbidity. Discussing options and goals as well as setting realistic expectations with the patient are essential in determining the optimal approach.

Medical Management—In medical literature, oral isotretinoin (13-cis-retinoic acid) has been the mainstay of therapy for steatocystoma, as its effect on the size and activity of sebaceous glands is hypothesized to decrease disease activity.^38,40 Interventional studies and case reports have exhibited varying degrees of effectiveness.^1,38-41 Some reports depict a reduction in the formation of new lesions and a decrease in the size of pre-existing lesions, some show mild delayed therapeutic efficacy, and others suggest exacerbation of the condition.^1,38-41 This outcome variability is attributed to isotretinoin’s preferential efficacy in treating inflammatory lesions.^40,42

Tetracycline derivatives and intralesional steroid injections also have been employed with some efficacy in patients with focal inflammatory SM and SMS.⁴³ There is limited evidence on the long-term outcomes of these interventions, and intralesional injections often are not recommended in conditions such as SM, in which there are many lesions present.

Surgical Management—Minimally invasive surgical procedures including drainage and resections have been used with varying efficacy in SS and SM. Typically, a 2- to 3-mm incision or sharp-tipped cautery is employed to puncture the cyst. Alternatively, radiofrequency probes with a 2.4-MHz frequency setting have been used to minimize incision size.⁴⁴ The contents then are expressed with manual pressure or forceps, and the cyst sac is extracted using forceps and/or a vein hook (eFigure 4).^44,45 The specific surgical techniques and their respective advantages and limitations are summarized in the eTable. Reported advantages and limitations of surgical techniques are derived from information provided by the authors of steatocystoma case reports, which are based on observations of a very limited sample size.

Laser Treatment—Various laser modalities have been used in the management of steatocystomas, including carbon dioxide lasers, erbium-doped yttrium aluminum garnet lasers, 1450-nm diode plus 1550-nm fractionated erbium-doped fiber lasers, and 1927-nm diode lasers.^54,55-57 These lasers are used to perforate the cyst before extirpation and have displayed advantages in minimizing scar length.⁵⁸ The super-pulse mode of carbon dioxide lasers demonstrates efficacy with minimal scarring and recurrence, and this mode is preferred to minimize thermal damage.^54,59 Furthermore, this modality can be especially useful in patients whose condition is refractory to other noninvasive options.⁵⁹ Similarly, the erbium-doped yttrium aluminum garnet laser was well tolerated with no complications noted.⁵⁵ The 1927-nm diode laser also displayed good outcomes as well as no recurrence.⁵⁷ With laser use, it is important to note that multiple treatments are needed to see optimal outcomes.⁵⁴ Moreover, laser settings must be carefully considered, especially in patients with Fitzpatrick skin type III or higher, and topical anti-inflammatory agents should be considered posttreatment to minimize complications.^54,59,60

Recommendations

For management of SS, we recommend conservative therapy of watchful observation, as scarring or postinflammatory pigment change may be brought on by medical or surgical therapy; however, if SS is cosmetically bothersome, laser or surgical excision can be done (eFigure 4).^4,43-53 It is important to counsel the patient on risks/benefits. For SM, watchful observation also is indicated; however, systemic therapies aimed at prevention may be the most efficacious by limiting disease progression, and oral tetracycline or isotretinoin may be tried.⁴ Tetracyclines have the risk for photosensitivity and are teratogenic, while isotretinoin is extremely teratogenic, requires laboratory monitoring and regular pregnancy tests in women, and often causes substantial mucosal dryness. If lesions are bothersome or refractory to these therapies, intralesional steroids or surgical/laser procedures can be tried throughout multiple visits.^43-53 For SMS, systemic therapies frequently are recommended. The risks of systemic tetracycline and isotretinoin therapies must be discussed. Patients with treatment-refractory SMS may require surgical excision or deroofing of sinus tracts.^43-53 This management is similar to that of HS and must be tailored to the patient.

Conclusion

Overall, steatocystomas are a relatively rare pathology, with a limited consensus on their etiology and management. This review summarizes the current knowledge on the condition to support clinicians in diagnosis and management, ranging from watchful waiting to surgical removal. By individualizing treatment plans, clinicians ultimately can optimize outcomes in patients with steatocystomas.

Steatocystomas are small sebum-filled cysts that typically manifest in the dermis and originate from sebaceous follicles. Although commonly asymptomatic, these lesions can manifest with pruritus or become infected, predisposing patients to further complications.¹ Steatocystomas can manifest as single (steatocystoma simplex [SS]) or numerous (steatocystoma multiplex [SM]) lesions; the lesions also can spontaneously rupture with characteristics that resemble hidradenitis suppurativa (HS)(steatocystoma multiplex suppurativa [SMS]).^1,2

Steatocystomas are relatively rare, and there is limited consensus in the published literature on the etiology and management of this condition. In this article, we present a comprehensive review of steatocystomas in the current literature. We highlight important features to consider when making the diagnosis and also offer recommendations for best-practice treatment.

Historical Background

Although not explicitly identified by name, the first documentation of steatocystomas is a case report published in 1873. In this account, the author described a patient who presented with approximately 250 flesh-colored dermal cysts across the body that varied in size.³ In 1899, the term steatocystoma multiple—derived from Greek roots meaning “fatty bag”—was first used.⁴

In 1982, almost a century later, Brownstein⁵ reported some of the earliest cases of SS. This solitary subtype is identical to SM on a microscopic level; however, unlike SM, this variant occurs as a single lesion that typically forms in adulthood and in the absence of family history. Other benign adnexal tumors (eg, pilomatricomas, pilar cysts, and sebaceous hyperplasias) also can manifest as either solitary or multiple lesions.

In 1976, McDonald and Reed⁶ reported the first known cases of patients with both SM and HS. At the time, the co-occurrence of these conditions was viewed as coincidental, but there were postulations of a shared inflammatory process and hereditary link⁶; it was not until 1982 that the term steatocystoma multiplex suppurativum was coined to describe this variant.⁷ Although rare, there have been multiple documented instances of SMS since. It has been suggested that the convergence of these conditions may indicate a shared follicular proliferation defect.⁸ Ongoing investigation is warranted to explain the underlying pathogenesis of this unique variant.

Epidemiology

The available epidemiologic data primarily relate to SM, the most common steatocystoma variant. Nevertheless, SM is a relatively rare condition, and the exact incidence and prevalence remain unknown.^8,9 Steatocystomas typically manifest in the first and second decades of life and have been observed in patients of both sexes, with studies demonstrating no notable sex bias.^4,9

Etiology and Pathophysiology

Steatocystomas can occur sporadically or may be inherited as an autosomal-dominant condition.⁴ Typically, SS tends to manifest as an isolated occurrence without any inherent genetic predisposition.⁵ Alternatively, SM may develop sporadically or be associated with a mutation in the keratin 17 gene (KRT17).⁴ Steatocystoma multiplex also has been associated with at least 4 different missense mutations, including N92H, R94H, and R94C, located on the long (q) arm of chromosome 17.^4,10-12

The keratin 17 gene is responsible for encoding the keratin 17 protein, a type I intermediate filament predominantly synthesized in the basal cells of epithelial tissue. This fibrous structural protein can regulate many processes, including inflammation and cell proliferation, and is found in regions such as the sebaceous glands, hair follicles, and eccrine sweat glands. Overexpression of KRT17 has been suggested in other cutaneous conditions, most notably psoriasis.¹² Despite KRT17’s many roles, it remains unclear why SM typically manifests with a myriad of sebum-containing cysts as the primary symptom.¹² Continued investigation into the genetic underpinnings of SM and the keratin 17 protein is necessary to further elucidate a more comprehensive understanding of this condition.

Hormonal influences have been suggested as a potential trigger for steatocystoma growth.^4,13 This condition is associated with dysfunction of the sebaceous glands, and, correspondingly, the incidence of disease is highest in pubertal patients, in whom androgen levels and sebum production are elevated.^4,13,14 Two cases of transgender men taking testosterone therapy presenting with steatocystomas provide additional clinical support for this association.¹⁵

Additionally, the use of immunomodulatory agents, such as ustekinumab (anti–interleukin 12/interleukin 23), has been shown to trigger SM. It is predicted that the reduced expression of certain interferons and interleukins may lead to downstream consequences in the keratin 17 pathway and lead to SM lesion formation in genetically susceptible individuals.¹⁶ Targeting these potential causes in the future may prove efficacious in the secondary prevention of familial SM manifestation or exacerbations.

Mutations in the KRT17 gene also have been implicated in pachyonychia congenita type 2 (PC-2).⁴ Marked by extensive systemic hyperkeratosis, PC-2 has been observed to coincide with SM in certain patients.^4,5 Interestingly, the location of the KRT17 mutations are identical in both PC-2 and SM.⁴ Although most individuals with hereditary SM do not exhibit the characteristic features of PC-2, mild nail and dental abnormalities have been observed in some SM cases.^4,10 This relationship suggests that SM may be a less severe variant of PC-2 or part of a complex polygenetic spectrum of disease.¹⁰ Further research is imperative to determine the exact nature and extent of the relationship between these conditions.

Clinical Manifestations

Steatocystomas are flesh-colored subcutaneous cysts that range in size from less than 3 mm to larger than 3 cm in diameter (Figure). They form within a single pilosebaceous unit and typically display firm attachment due to their origination in the dermis.^2,7,17 Steatocystomas generally contain lipid material, and less frequently, keratin and hair shafts, distinguishing them as the only “true” sebaceous cysts.¹⁸ Their color can range from flesh-toned to yellow, with reports of occasional dark-blue shades and calcifications.^19,20 Steatocystomas can persist indefinitely, and they usually are asymptomatic.

Diagnosis of steatocystoma is confirmed by biopsy.⁴ Steatocystomas are characterized by a dermal cyst lined by stratified squamous cell epithelium (eFigures 1 and 2).²¹ Classically they feature flattened sebaceous lobules, multinucleated giant cells, and abortive hair follicles. The lining of these cysts is marked by lymphocytic infiltrate and a dense, wrinkled, eosinophilic keratin cuticle that replaces the granular layer.²² The cyst maintains an epidermal connection through a follicular infundibulum characterized by clumps of keratinocytes, sebocytes, corneocytes, and/or hair follicles.⁷ Aspirated contents reveal crystalline structures and anucleate squamous cells upon microscopic analysis. That being said, variable histologic findings of steatocystomas have been described.²³

Steatocystoma simplex, as the name implies, classifies a single isolated steatocystoma. This subtype exhibits similar histopathologic and clinical features to the other subtypes of steatocystomas. Notably, SS is not associated with a genetic mutation and is not an inherited condition within families.⁵ Steatocystoma multiplex manifests with many steatocystomas, often distributed widely across the body.^3,4 The chest, axillae, and groin are the most common locations; however, these cysts can manifest on the face, back, abdomen, and extremities.^4,18-22 Rare occurrences of SM limited to the face, scalp, and distal extremities have been documented.^18,21,24,25 Due to the possibility of an autosomal-dominant inheritance, it is advisable to take a comprehensive family history in patients for whom SM is in the differential.¹⁷

Steatocystoma multiplex—especially familial variants—has been shown to develop in conjunction with other dermatologic conditions, including eruptive vellus hair (EVH) cysts, persistent infantile milia, and epidermoid/dermoid cysts.²⁶ While some investigators regard these as separate entities due to their varied genetic etiology, it has been suggested that these conditions may be related and that the diagnosis is determined by the location of cyst origin along the sebaceous ducts.^26,27 Other dermatologic conditions and lesions that frequently manifest comorbidly with SM include hidrocystomas, syringomas, pilonidal cysts, lichen planus, nodulocystic acne, trichotillomania, trichoblastomas, trichoepithelioma, HS, keratoacanthomas, acrokeratosis verruciformis of Hopf, and embryonal hair formation. Steatocystoma multiplex, manifesting comorbidly with dental and orofacial malformations (eg, partial noneruption of secondary teeth, natal and defective teeth, and bilateral preauricular sinuses) has been classified as SM natal teeth syndrome.⁶

Steatocystoma multiplex suppurativa is a rare and serious variant of SM characterized by inflammation, cyst rupture, sinus tract formation, and scarring.²⁴ Patients with SMS typically have multiple intact SM cysts, which can aid in differentiation from HS.^2,24 Steatocystoma multiplex suppurativa is associated with more complications than SS and SM, including cyst perforation, development of purulent and/or foul-smelling discharge, infection, scarring, pain, and overall discomfort.²

Given its rarity and the potential manifestations that overlap with other conditions, steatocystomas easily can be misdiagnosed. In some clinical instances, EVHs may share similar characteristics with SM; however, certain distinguishing features exist, including a central tuft of protruding hairs and different expressed contents, such as the vellus hair shafts, from the cyst’s lumen.²⁸ Furthermore, histologic examination of EVHs reveals epidermoid keratinization of the lining as well as a lack of sebaceous glands within the wall.^28,29 Other similar conditions include epidermoid cysts, pilar cysts, lipomas, epidermal inclusion cysts, dermoid cysts, sebaceous hyperplasia, folliculitis, xanthomas, neurofibromatosis, and syringomas.³⁰ Occasionally, SMS can be mistaken for HS or acne conglobata, and SM lesions with a facial distribution can mimic acne vulgaris.^1,31 These conditions should be excluded before a diagnosis of SS, SM, or SMS is made. 

Importantly, SM is visually indistinguishable from subcutaneous metastasis on physical examination, and there are reports of oncologic conditions (eg, pulmonary adenocarcinoma metastasized to the skin) being mistaken for SS or SM.³² Therefore, a thorough clinical examination, histopathologic analysis, and potential use of other imaging modalities such as ultrasonography (US) are needed to ensure an accurate diagnosis.

Ultrasonography has demonstrated utility in diagnosing steatocystomas.^33-35 Steatocystomas have incidentally been found on routine mammograms and can demonstrate well-defined circular nodules with radiolucent characteristics and a thin radiodense outline.^33,36 Homogeneous hypoechoic nodules within the dermis without posterior acoustic features generally are observed (eFigure 3).^33,37 In patients declining biopsy, US may be useful in further characterization of an unknown lesion. Color Doppler US can be used to distinguish SMS from HS. Specifically, SM typically exhibits an absence of Doppler signaling due to a lack of vascularity, providing a helpful diagnostic clue for the SMS variant.³³

Management and Treatment Options

There is no established standard treatment for steatocystomas; therefore, the approach to management is contingent on clinical presentation and patient preferences. Various medical, surgical, and laser management options are available, each with its own advantages and limitations. Treatment of SM is difficult due to the large number of lesions.³⁸ In many cases, continued observation is a viable treatment option, as most SS and SM lesions are asymptomatic; however, cosmetic concerns can be debilitating for patients with SM and may warrant intervention.³⁹ More extensive medical and surgical management often are necessary in SMS due to associated morbidity. Discussing options and goals as well as setting realistic expectations with the patient are essential in determining the optimal approach.

Medical Management—In medical literature, oral isotretinoin (13-cis-retinoic acid) has been the mainstay of therapy for steatocystoma, as its effect on the size and activity of sebaceous glands is hypothesized to decrease disease activity.^38,40 Interventional studies and case reports have exhibited varying degrees of effectiveness.^1,38-41 Some reports depict a reduction in the formation of new lesions and a decrease in the size of pre-existing lesions, some show mild delayed therapeutic efficacy, and others suggest exacerbation of the condition.^1,38-41 This outcome variability is attributed to isotretinoin’s preferential efficacy in treating inflammatory lesions.^40,42

Tetracycline derivatives and intralesional steroid injections also have been employed with some efficacy in patients with focal inflammatory SM and SMS.⁴³ There is limited evidence on the long-term outcomes of these interventions, and intralesional injections often are not recommended in conditions such as SM, in which there are many lesions present.

Surgical Management—Minimally invasive surgical procedures including drainage and resections have been used with varying efficacy in SS and SM. Typically, a 2- to 3-mm incision or sharp-tipped cautery is employed to puncture the cyst. Alternatively, radiofrequency probes with a 2.4-MHz frequency setting have been used to minimize incision size.⁴⁴ The contents then are expressed with manual pressure or forceps, and the cyst sac is extracted using forceps and/or a vein hook (eFigure 4).^44,45 The specific surgical techniques and their respective advantages and limitations are summarized in the eTable. Reported advantages and limitations of surgical techniques are derived from information provided by the authors of steatocystoma case reports, which are based on observations of a very limited sample size.

Laser Treatment—Various laser modalities have been used in the management of steatocystomas, including carbon dioxide lasers, erbium-doped yttrium aluminum garnet lasers, 1450-nm diode plus 1550-nm fractionated erbium-doped fiber lasers, and 1927-nm diode lasers.^54,55-57 These lasers are used to perforate the cyst before extirpation and have displayed advantages in minimizing scar length.⁵⁸ The super-pulse mode of carbon dioxide lasers demonstrates efficacy with minimal scarring and recurrence, and this mode is preferred to minimize thermal damage.^54,59 Furthermore, this modality can be especially useful in patients whose condition is refractory to other noninvasive options.⁵⁹ Similarly, the erbium-doped yttrium aluminum garnet laser was well tolerated with no complications noted.⁵⁵ The 1927-nm diode laser also displayed good outcomes as well as no recurrence.⁵⁷ With laser use, it is important to note that multiple treatments are needed to see optimal outcomes.⁵⁴ Moreover, laser settings must be carefully considered, especially in patients with Fitzpatrick skin type III or higher, and topical anti-inflammatory agents should be considered posttreatment to minimize complications.^54,59,60

Recommendations

For management of SS, we recommend conservative therapy of watchful observation, as scarring or postinflammatory pigment change may be brought on by medical or surgical therapy; however, if SS is cosmetically bothersome, laser or surgical excision can be done (eFigure 4).^4,43-53 It is important to counsel the patient on risks/benefits. For SM, watchful observation also is indicated; however, systemic therapies aimed at prevention may be the most efficacious by limiting disease progression, and oral tetracycline or isotretinoin may be tried.⁴ Tetracyclines have the risk for photosensitivity and are teratogenic, while isotretinoin is extremely teratogenic, requires laboratory monitoring and regular pregnancy tests in women, and often causes substantial mucosal dryness. If lesions are bothersome or refractory to these therapies, intralesional steroids or surgical/laser procedures can be tried throughout multiple visits.^43-53 For SMS, systemic therapies frequently are recommended. The risks of systemic tetracycline and isotretinoin therapies must be discussed. Patients with treatment-refractory SMS may require surgical excision or deroofing of sinus tracts.^43-53 This management is similar to that of HS and must be tailored to the patient.

Conclusion

Overall, steatocystomas are a relatively rare pathology, with a limited consensus on their etiology and management. This review summarizes the current knowledge on the condition to support clinicians in diagnosis and management, ranging from watchful waiting to surgical removal. By individualizing treatment plans, clinicians ultimately can optimize outcomes in patients with steatocystomas.

Operational risk management (ORM) refers to the systematic identification and assessment of daily operational risks within an organization designed to mitigate negative financial, reputational, and safety outcomes while maximizing efficiency and achievement of objectives.¹ Operational risk management is indispensable to modern military operations, optimizing mission readiness while minimizing complications and personnel morbidity. Application of ORM in medicine holds considerable promise due to the emphasis on precise and efficient decision-making in high-stakes environments, where the margin for error is minimal. In this article, we propose integrating ORM principles into dermatologic surgery to enhance patient-centered care through improved counseling, risk assessment, and procedural outcomes. 

Principles and Processes of ORM

The ORM framework is built on 4 fundamental principles: accept risk when benefits outweigh the cost, accept no unnecessary risk, anticipate and manage risk by planning, and make risk decisions at the right level.² These principles form the foundation of the ORM’s systematic 5-step approach to identify hazards, assess hazards, make risk decisions, implement controls, and supervise. Key to the ORM process is the use of risk assessment codes and the risk assessment matrix to quantify and prioritize risks. Risk assessment codes are numerical values assigned to hazards based on their assessed severity and probability. The risk assessment matrix is a tool that plots the severity of a hazard against its probability. By locating a hazard on the matrix, users can visualize its risk level in terms of severity and probability. Building and using the risk assessment matrix begins with determining severity by assessing the potential impact of a hazard and categorizing it into levels (catastrophic, critical, moderate, or negligible). Next, probability is determined by evaluating the likelihood of occurrence (frequent, likely, occasional, seldom, or unlikely). Finally, the severity and probability are combined to assign a risk assessment code, which indicates the risk level and helps visualize criticality. Systematically applying these principles and processes enables users to make informed decisions that balance mission objectives with safety.

Proposed Framework for ORM in Dermatology Surgery

Current risk mitigation in dermatologic surgery includes strict medication oversight, sterilization protocols, and photography to prevent wrong-site surgeries. Preoperative risk assessment through conducting a thorough patient history is vital, considering factors such as pregnancy, allergies, bleeding history, cardiac devices, and keloid propensity, all of which impact surgical outcomes.^3-5 After gathering the patient’s history, dermatologists determine appropriateness for surgery and its inherent risks, typically via an informed consent process outlining the diagnosis and procedure purpose as well as a list of risks, benefits, and alternatives, including forgoing treatment.

Importantly, the standard process for dermatologic risk evaluation often lacks a comprehensive systematic approach seen in other higher-risk surgical fields. For example, general surgeons frequently utilize risk assessment calculators such as the one developed by the American College of Surgeons’ National Surgical Quality Improvement Program to estimate surgical complications.⁶ While specific guidelines exist for evaluating factors such as hypertension or anticoagulant use, no single tool synthesizes all patient risk factors for a unified assessment. Therefore, we propose integrating ORM as a structured decision-making process that offers a more consistent means for dermatologists to evaluate, synthesize, categorize, and present risks to patients. Our proposed process includes translating military mishap severity into a framework that helps patients better understand decisions about their health care when using ORM (eTable 1). The proposed process also provides dermatologists with a systematic, proactive, and iterative approach to assessing risks that allows them to consistently qualify medical decisions (eTable 2).

Patients often struggle to understand surgical risk severity, including overestimating the risks of routine minor procedures or underestimating the risks of more intensive procedures.^7,8 Incorporating ORM into patient communication mirrors the provider’s process but uses patient-friendly terminology—it is discussion based and integrates patient preferences and tolerances (eTable 2). These steps often occur informally in dermatologic counseling; however, an organized structured approach, especially using a visual aid such as a risk assessment matrix, enhances patient comprehension, recall, and satisfaction.⁹

Practical Scenarios 

Integrating ORM into dermatologic surgery is a proactive iterative process for both provider decision-making and patient communication. Leveraging a risk assessment matrix as a visual aid allows for clear identification, evaluation, and mitigation of hazards, fostering collaborative choices with regard to the treatment approach. Here we provide 2 case scenarios highlighting how ORM and the risk assessment matrix can be used in the management of a complex patient with a lesion in a high-risk location as well as to address patient anxiety and comorbidities. It is important to note that the way the matrices are completed in the examples provided may differ compared to other providers. The purpose of ORM is not to dictate risk categories but to serve as a tool for providers to take their own experiences and knowledge of the patient to guide their decision-making and counseling processes. 

Case Scenario 1—An elderly man with a history of diabetes, cardiovascular accident, coronary artery bypass grafting, and multiple squamous cell carcinoma excisions presents for evaluation of a 1-cm squamous cell carcinoma in situ on the left leg. His current medications include an anticoagulant and antihypertensives. 

In this scenario, the provider would apply ORM by identifying and assessing hazards, making risk decisions, implementing controls, and supervising care. 

General hazards for excision on the leg include bleeding, infection, scarring, pain, delayed healing, activity limitations, and possible further procedures. Before the visit, the provider should prepare baseline risk matrices for 2 potential treatment options: wide local excision and electrodessication and curettage. For example, surgical bleeding may be assessed as negligible severity and almost certain probability for a general excision.

Next, the provider would incorporate the patient’s unique history in the risk matrices (eFigures 1 and 2). The patient’s use of an anticoagulant indicates a bleeding risk; therefore, the provider may shift the severity to minimal clinical concern, understanding the need for enhanced perioperative management. The history of diabetes also has a considerable impact on wound healing, so the provider might elevate the probability of delayed wound healing from rare to unlikely and the severity from moderate to severe. The prior cardiovascular accident also raises concerns about mobility and activity limitations during recovery, which could be escalated from minimal to moderate clinical concern if postoperative limitations on ambulation increase the risk for new clots. Based on this internal assessment, the provider identifies which risks are elevated and require further attention and discussion with the patient, helping tailor the counseling approach and potential treatment plan. The provider should begin to consider initial control measures such as coordinating anticoagulant management, ensuring diabetes is well controlled, and planning for postoperative ambulation support.

Once the provider has conducted the internal assessment, the ORM matrices become powerful tools for shared decision-making with the patient. The provider can walk the patient through the procedures and their common risks and then explain how their individual situation modifies the risks. The visual and explicit upgrade on the matrices allows the patient to clearly see how unique factors influence their personal risk profile, moving beyond a generic list of complications. The provider then should engage the patient in a discussion about their risk tolerance, which is crucial for mutual agreement on whether to proceed with treatment and, if so, which procedure is most appropriate given the patient’s comfort level with their individualized risk profile. Then the provider should reinforce the proactive steps planned to mitigate the identified risks to provide assurance and reinforce the collaborative approach to safety. 

Finally, throughout the preoperative and postoperative phases, the provider should continuously monitor the patient’s condition and the effectiveness of the control measures, adjusting the plan as needed. 

In this scenario, both the provider and the patient participated in the risk assessment, with the provider completing the assessment before the visit and presenting it to the patient or performing the assessment in real time with the patient present to explain the reasoning behind assignment of risk based on each procedure and the patient’s unique risk factors. 

Case Scenario 2—A 38-year-old woman with a history of hypertension and procedural anxiety presents for evaluation of a biopsy-proven basal cell carcinoma on the nasal ala. The patient is taking diltiazem for hypertension and is compliant with her medication. Her blood pressure at the current visit is 148/96 mm Hg, which she attributes to white coat syndrome. Mohs micrographic surgery generally is the gold standard treatment for this case.

The provider’s ORM process, conducted either before or in real time during the visit, would begin with identification and assessment of the hazards. For Mohs surgery on the nasal ala, common hazards would include scarring, pain, infection, bleeding, and potential cosmetic distortion. Unique to this patient are the procedural anxiety and hypertension. 

To populate the risk assessment matrix (eFigure 3), the provider would first map the baseline risks of Mohs surgery, which include considerable scarring as a moderate clinical concern but a seldom probability. Because the patient’s procedural anxiety directly increases the probability of intraoperative distress or elevated blood pressure during the procedure, the provider might assess patient distress/anxiety as a moderate clinical concern with a likely probability. While the patient’s blood pressure is controlled, the white coat syndrome raises the probability of hypertensive urgency/emergency during surgery; this might be elevated from unlikely to occasional or likely probability, and severity might increase from minimal to moderate due to its potential impact on procedural safety. The provider should consider strategies to address these elevated risks during the consultation. Then, as part of preprocedure planning, the provider should consider discussing anxiolytics, emphasizing medication compliance, and ensuring a calm environment for the patient’s surgery.

For this patient, the risk assessment matrix becomes a powerful tool to address fears and proactively manage her unique risk factors. To start the counseling process, the provider should explain the procedure, its benefits, and potential adverse effects. Then, the patient’s individualized risks can be visualized using the matrix, which also is an opportunity for reassurance, as it can alleviate patient fears by contextualizing rare but impactful outcomes.⁹

Now the provider can assess the patient’s risk tolerance. This discussion ensures that the patient’s comfort level and preferences are central to the treatment decision, even for a gold-standard procedure such as Mohs surgery. By listening and responding to the patient’s input, the provider can build trust and discuss strategies that can help control for some risk factors.

Finally, the provider would re-evaluate throughout the procedure by continuously monitoring the patient’s anxiety and vital signs. The provider should also be ready to adjust pain management or employ anxiety-reduction techniques.

Final Thoughts

Reviewing the risk assessment matrix can be an effective way to nonjudgmentally discuss a patient’s unique risk factors and provide a complete understanding of the planned treatment or procedure. It conveys to the patient that, as the provider, you are taking their health seriously when considering treatment options and can be a means to build patient rapport and trust. This approach mirrors risk communication strategies long employed in military operational planning, where transparency and structured risk evaluation are essential to maintaining mission readiness and unit cohesion.

Operational risk management (ORM) refers to the systematic identification and assessment of daily operational risks within an organization designed to mitigate negative financial, reputational, and safety outcomes while maximizing efficiency and achievement of objectives.¹ Operational risk management is indispensable to modern military operations, optimizing mission readiness while minimizing complications and personnel morbidity. Application of ORM in medicine holds considerable promise due to the emphasis on precise and efficient decision-making in high-stakes environments, where the margin for error is minimal. In this article, we propose integrating ORM principles into dermatologic surgery to enhance patient-centered care through improved counseling, risk assessment, and procedural outcomes. 

Principles and Processes of ORM

The ORM framework is built on 4 fundamental principles: accept risk when benefits outweigh the cost, accept no unnecessary risk, anticipate and manage risk by planning, and make risk decisions at the right level.² These principles form the foundation of the ORM’s systematic 5-step approach to identify hazards, assess hazards, make risk decisions, implement controls, and supervise. Key to the ORM process is the use of risk assessment codes and the risk assessment matrix to quantify and prioritize risks. Risk assessment codes are numerical values assigned to hazards based on their assessed severity and probability. The risk assessment matrix is a tool that plots the severity of a hazard against its probability. By locating a hazard on the matrix, users can visualize its risk level in terms of severity and probability. Building and using the risk assessment matrix begins with determining severity by assessing the potential impact of a hazard and categorizing it into levels (catastrophic, critical, moderate, or negligible). Next, probability is determined by evaluating the likelihood of occurrence (frequent, likely, occasional, seldom, or unlikely). Finally, the severity and probability are combined to assign a risk assessment code, which indicates the risk level and helps visualize criticality. Systematically applying these principles and processes enables users to make informed decisions that balance mission objectives with safety.

Proposed Framework for ORM in Dermatology Surgery

Current risk mitigation in dermatologic surgery includes strict medication oversight, sterilization protocols, and photography to prevent wrong-site surgeries. Preoperative risk assessment through conducting a thorough patient history is vital, considering factors such as pregnancy, allergies, bleeding history, cardiac devices, and keloid propensity, all of which impact surgical outcomes.^3-5 After gathering the patient’s history, dermatologists determine appropriateness for surgery and its inherent risks, typically via an informed consent process outlining the diagnosis and procedure purpose as well as a list of risks, benefits, and alternatives, including forgoing treatment.

Importantly, the standard process for dermatologic risk evaluation often lacks a comprehensive systematic approach seen in other higher-risk surgical fields. For example, general surgeons frequently utilize risk assessment calculators such as the one developed by the American College of Surgeons’ National Surgical Quality Improvement Program to estimate surgical complications.⁶ While specific guidelines exist for evaluating factors such as hypertension or anticoagulant use, no single tool synthesizes all patient risk factors for a unified assessment. Therefore, we propose integrating ORM as a structured decision-making process that offers a more consistent means for dermatologists to evaluate, synthesize, categorize, and present risks to patients. Our proposed process includes translating military mishap severity into a framework that helps patients better understand decisions about their health care when using ORM (eTable 1). The proposed process also provides dermatologists with a systematic, proactive, and iterative approach to assessing risks that allows them to consistently qualify medical decisions (eTable 2).

Patients often struggle to understand surgical risk severity, including overestimating the risks of routine minor procedures or underestimating the risks of more intensive procedures.^7,8 Incorporating ORM into patient communication mirrors the provider’s process but uses patient-friendly terminology—it is discussion based and integrates patient preferences and tolerances (eTable 2). These steps often occur informally in dermatologic counseling; however, an organized structured approach, especially using a visual aid such as a risk assessment matrix, enhances patient comprehension, recall, and satisfaction.⁹

Practical Scenarios 

Integrating ORM into dermatologic surgery is a proactive iterative process for both provider decision-making and patient communication. Leveraging a risk assessment matrix as a visual aid allows for clear identification, evaluation, and mitigation of hazards, fostering collaborative choices with regard to the treatment approach. Here we provide 2 case scenarios highlighting how ORM and the risk assessment matrix can be used in the management of a complex patient with a lesion in a high-risk location as well as to address patient anxiety and comorbidities. It is important to note that the way the matrices are completed in the examples provided may differ compared to other providers. The purpose of ORM is not to dictate risk categories but to serve as a tool for providers to take their own experiences and knowledge of the patient to guide their decision-making and counseling processes. 

Case Scenario 1—An elderly man with a history of diabetes, cardiovascular accident, coronary artery bypass grafting, and multiple squamous cell carcinoma excisions presents for evaluation of a 1-cm squamous cell carcinoma in situ on the left leg. His current medications include an anticoagulant and antihypertensives. 

In this scenario, the provider would apply ORM by identifying and assessing hazards, making risk decisions, implementing controls, and supervising care. 

General hazards for excision on the leg include bleeding, infection, scarring, pain, delayed healing, activity limitations, and possible further procedures. Before the visit, the provider should prepare baseline risk matrices for 2 potential treatment options: wide local excision and electrodessication and curettage. For example, surgical bleeding may be assessed as negligible severity and almost certain probability for a general excision.

Next, the provider would incorporate the patient’s unique history in the risk matrices (eFigures 1 and 2). The patient’s use of an anticoagulant indicates a bleeding risk; therefore, the provider may shift the severity to minimal clinical concern, understanding the need for enhanced perioperative management. The history of diabetes also has a considerable impact on wound healing, so the provider might elevate the probability of delayed wound healing from rare to unlikely and the severity from moderate to severe. The prior cardiovascular accident also raises concerns about mobility and activity limitations during recovery, which could be escalated from minimal to moderate clinical concern if postoperative limitations on ambulation increase the risk for new clots. Based on this internal assessment, the provider identifies which risks are elevated and require further attention and discussion with the patient, helping tailor the counseling approach and potential treatment plan. The provider should begin to consider initial control measures such as coordinating anticoagulant management, ensuring diabetes is well controlled, and planning for postoperative ambulation support.

Once the provider has conducted the internal assessment, the ORM matrices become powerful tools for shared decision-making with the patient. The provider can walk the patient through the procedures and their common risks and then explain how their individual situation modifies the risks. The visual and explicit upgrade on the matrices allows the patient to clearly see how unique factors influence their personal risk profile, moving beyond a generic list of complications. The provider then should engage the patient in a discussion about their risk tolerance, which is crucial for mutual agreement on whether to proceed with treatment and, if so, which procedure is most appropriate given the patient’s comfort level with their individualized risk profile. Then the provider should reinforce the proactive steps planned to mitigate the identified risks to provide assurance and reinforce the collaborative approach to safety. 

Finally, throughout the preoperative and postoperative phases, the provider should continuously monitor the patient’s condition and the effectiveness of the control measures, adjusting the plan as needed. 

In this scenario, both the provider and the patient participated in the risk assessment, with the provider completing the assessment before the visit and presenting it to the patient or performing the assessment in real time with the patient present to explain the reasoning behind assignment of risk based on each procedure and the patient’s unique risk factors. 

Case Scenario 2—A 38-year-old woman with a history of hypertension and procedural anxiety presents for evaluation of a biopsy-proven basal cell carcinoma on the nasal ala. The patient is taking diltiazem for hypertension and is compliant with her medication. Her blood pressure at the current visit is 148/96 mm Hg, which she attributes to white coat syndrome. Mohs micrographic surgery generally is the gold standard treatment for this case.

The provider’s ORM process, conducted either before or in real time during the visit, would begin with identification and assessment of the hazards. For Mohs surgery on the nasal ala, common hazards would include scarring, pain, infection, bleeding, and potential cosmetic distortion. Unique to this patient are the procedural anxiety and hypertension. 

To populate the risk assessment matrix (eFigure 3), the provider would first map the baseline risks of Mohs surgery, which include considerable scarring as a moderate clinical concern but a seldom probability. Because the patient’s procedural anxiety directly increases the probability of intraoperative distress or elevated blood pressure during the procedure, the provider might assess patient distress/anxiety as a moderate clinical concern with a likely probability. While the patient’s blood pressure is controlled, the white coat syndrome raises the probability of hypertensive urgency/emergency during surgery; this might be elevated from unlikely to occasional or likely probability, and severity might increase from minimal to moderate due to its potential impact on procedural safety. The provider should consider strategies to address these elevated risks during the consultation. Then, as part of preprocedure planning, the provider should consider discussing anxiolytics, emphasizing medication compliance, and ensuring a calm environment for the patient’s surgery.

For this patient, the risk assessment matrix becomes a powerful tool to address fears and proactively manage her unique risk factors. To start the counseling process, the provider should explain the procedure, its benefits, and potential adverse effects. Then, the patient’s individualized risks can be visualized using the matrix, which also is an opportunity for reassurance, as it can alleviate patient fears by contextualizing rare but impactful outcomes.⁹

Now the provider can assess the patient’s risk tolerance. This discussion ensures that the patient’s comfort level and preferences are central to the treatment decision, even for a gold-standard procedure such as Mohs surgery. By listening and responding to the patient’s input, the provider can build trust and discuss strategies that can help control for some risk factors.

Finally, the provider would re-evaluate throughout the procedure by continuously monitoring the patient’s anxiety and vital signs. The provider should also be ready to adjust pain management or employ anxiety-reduction techniques.

Final Thoughts

Reviewing the risk assessment matrix can be an effective way to nonjudgmentally discuss a patient’s unique risk factors and provide a complete understanding of the planned treatment or procedure. It conveys to the patient that, as the provider, you are taking their health seriously when considering treatment options and can be a means to build patient rapport and trust. This approach mirrors risk communication strategies long employed in military operational planning, where transparency and structured risk evaluation are essential to maintaining mission readiness and unit cohesion.

Operational risk management (ORM) refers to the systematic identification and assessment of daily operational risks within an organization designed to mitigate negative financial, reputational, and safety outcomes while maximizing efficiency and achievement of objectives.¹ Operational risk management is indispensable to modern military operations, optimizing mission readiness while minimizing complications and personnel morbidity. Application of ORM in medicine holds considerable promise due to the emphasis on precise and efficient decision-making in high-stakes environments, where the margin for error is minimal. In this article, we propose integrating ORM principles into dermatologic surgery to enhance patient-centered care through improved counseling, risk assessment, and procedural outcomes. 

Principles and Processes of ORM

The ORM framework is built on 4 fundamental principles: accept risk when benefits outweigh the cost, accept no unnecessary risk, anticipate and manage risk by planning, and make risk decisions at the right level.² These principles form the foundation of the ORM’s systematic 5-step approach to identify hazards, assess hazards, make risk decisions, implement controls, and supervise. Key to the ORM process is the use of risk assessment codes and the risk assessment matrix to quantify and prioritize risks. Risk assessment codes are numerical values assigned to hazards based on their assessed severity and probability. The risk assessment matrix is a tool that plots the severity of a hazard against its probability. By locating a hazard on the matrix, users can visualize its risk level in terms of severity and probability. Building and using the risk assessment matrix begins with determining severity by assessing the potential impact of a hazard and categorizing it into levels (catastrophic, critical, moderate, or negligible). Next, probability is determined by evaluating the likelihood of occurrence (frequent, likely, occasional, seldom, or unlikely). Finally, the severity and probability are combined to assign a risk assessment code, which indicates the risk level and helps visualize criticality. Systematically applying these principles and processes enables users to make informed decisions that balance mission objectives with safety.

Proposed Framework for ORM in Dermatology Surgery

Current risk mitigation in dermatologic surgery includes strict medication oversight, sterilization protocols, and photography to prevent wrong-site surgeries. Preoperative risk assessment through conducting a thorough patient history is vital, considering factors such as pregnancy, allergies, bleeding history, cardiac devices, and keloid propensity, all of which impact surgical outcomes.^3-5 After gathering the patient’s history, dermatologists determine appropriateness for surgery and its inherent risks, typically via an informed consent process outlining the diagnosis and procedure purpose as well as a list of risks, benefits, and alternatives, including forgoing treatment.

Importantly, the standard process for dermatologic risk evaluation often lacks a comprehensive systematic approach seen in other higher-risk surgical fields. For example, general surgeons frequently utilize risk assessment calculators such as the one developed by the American College of Surgeons’ National Surgical Quality Improvement Program to estimate surgical complications.⁶ While specific guidelines exist for evaluating factors such as hypertension or anticoagulant use, no single tool synthesizes all patient risk factors for a unified assessment. Therefore, we propose integrating ORM as a structured decision-making process that offers a more consistent means for dermatologists to evaluate, synthesize, categorize, and present risks to patients. Our proposed process includes translating military mishap severity into a framework that helps patients better understand decisions about their health care when using ORM (eTable 1). The proposed process also provides dermatologists with a systematic, proactive, and iterative approach to assessing risks that allows them to consistently qualify medical decisions (eTable 2).

Patients often struggle to understand surgical risk severity, including overestimating the risks of routine minor procedures or underestimating the risks of more intensive procedures.^7,8 Incorporating ORM into patient communication mirrors the provider’s process but uses patient-friendly terminology—it is discussion based and integrates patient preferences and tolerances (eTable 2). These steps often occur informally in dermatologic counseling; however, an organized structured approach, especially using a visual aid such as a risk assessment matrix, enhances patient comprehension, recall, and satisfaction.⁹

Practical Scenarios 

Integrating ORM into dermatologic surgery is a proactive iterative process for both provider decision-making and patient communication. Leveraging a risk assessment matrix as a visual aid allows for clear identification, evaluation, and mitigation of hazards, fostering collaborative choices with regard to the treatment approach. Here we provide 2 case scenarios highlighting how ORM and the risk assessment matrix can be used in the management of a complex patient with a lesion in a high-risk location as well as to address patient anxiety and comorbidities. It is important to note that the way the matrices are completed in the examples provided may differ compared to other providers. The purpose of ORM is not to dictate risk categories but to serve as a tool for providers to take their own experiences and knowledge of the patient to guide their decision-making and counseling processes. 

Case Scenario 1—An elderly man with a history of diabetes, cardiovascular accident, coronary artery bypass grafting, and multiple squamous cell carcinoma excisions presents for evaluation of a 1-cm squamous cell carcinoma in situ on the left leg. His current medications include an anticoagulant and antihypertensives. 

In this scenario, the provider would apply ORM by identifying and assessing hazards, making risk decisions, implementing controls, and supervising care. 

General hazards for excision on the leg include bleeding, infection, scarring, pain, delayed healing, activity limitations, and possible further procedures. Before the visit, the provider should prepare baseline risk matrices for 2 potential treatment options: wide local excision and electrodessication and curettage. For example, surgical bleeding may be assessed as negligible severity and almost certain probability for a general excision.

Next, the provider would incorporate the patient’s unique history in the risk matrices (eFigures 1 and 2). The patient’s use of an anticoagulant indicates a bleeding risk; therefore, the provider may shift the severity to minimal clinical concern, understanding the need for enhanced perioperative management. The history of diabetes also has a considerable impact on wound healing, so the provider might elevate the probability of delayed wound healing from rare to unlikely and the severity from moderate to severe. The prior cardiovascular accident also raises concerns about mobility and activity limitations during recovery, which could be escalated from minimal to moderate clinical concern if postoperative limitations on ambulation increase the risk for new clots. Based on this internal assessment, the provider identifies which risks are elevated and require further attention and discussion with the patient, helping tailor the counseling approach and potential treatment plan. The provider should begin to consider initial control measures such as coordinating anticoagulant management, ensuring diabetes is well controlled, and planning for postoperative ambulation support.

Once the provider has conducted the internal assessment, the ORM matrices become powerful tools for shared decision-making with the patient. The provider can walk the patient through the procedures and their common risks and then explain how their individual situation modifies the risks. The visual and explicit upgrade on the matrices allows the patient to clearly see how unique factors influence their personal risk profile, moving beyond a generic list of complications. The provider then should engage the patient in a discussion about their risk tolerance, which is crucial for mutual agreement on whether to proceed with treatment and, if so, which procedure is most appropriate given the patient’s comfort level with their individualized risk profile. Then the provider should reinforce the proactive steps planned to mitigate the identified risks to provide assurance and reinforce the collaborative approach to safety. 

Finally, throughout the preoperative and postoperative phases, the provider should continuously monitor the patient’s condition and the effectiveness of the control measures, adjusting the plan as needed. 

In this scenario, both the provider and the patient participated in the risk assessment, with the provider completing the assessment before the visit and presenting it to the patient or performing the assessment in real time with the patient present to explain the reasoning behind assignment of risk based on each procedure and the patient’s unique risk factors. 

Case Scenario 2—A 38-year-old woman with a history of hypertension and procedural anxiety presents for evaluation of a biopsy-proven basal cell carcinoma on the nasal ala. The patient is taking diltiazem for hypertension and is compliant with her medication. Her blood pressure at the current visit is 148/96 mm Hg, which she attributes to white coat syndrome. Mohs micrographic surgery generally is the gold standard treatment for this case.

The provider’s ORM process, conducted either before or in real time during the visit, would begin with identification and assessment of the hazards. For Mohs surgery on the nasal ala, common hazards would include scarring, pain, infection, bleeding, and potential cosmetic distortion. Unique to this patient are the procedural anxiety and hypertension. 

To populate the risk assessment matrix (eFigure 3), the provider would first map the baseline risks of Mohs surgery, which include considerable scarring as a moderate clinical concern but a seldom probability. Because the patient’s procedural anxiety directly increases the probability of intraoperative distress or elevated blood pressure during the procedure, the provider might assess patient distress/anxiety as a moderate clinical concern with a likely probability. While the patient’s blood pressure is controlled, the white coat syndrome raises the probability of hypertensive urgency/emergency during surgery; this might be elevated from unlikely to occasional or likely probability, and severity might increase from minimal to moderate due to its potential impact on procedural safety. The provider should consider strategies to address these elevated risks during the consultation. Then, as part of preprocedure planning, the provider should consider discussing anxiolytics, emphasizing medication compliance, and ensuring a calm environment for the patient’s surgery.

For this patient, the risk assessment matrix becomes a powerful tool to address fears and proactively manage her unique risk factors. To start the counseling process, the provider should explain the procedure, its benefits, and potential adverse effects. Then, the patient’s individualized risks can be visualized using the matrix, which also is an opportunity for reassurance, as it can alleviate patient fears by contextualizing rare but impactful outcomes.⁹

Now the provider can assess the patient’s risk tolerance. This discussion ensures that the patient’s comfort level and preferences are central to the treatment decision, even for a gold-standard procedure such as Mohs surgery. By listening and responding to the patient’s input, the provider can build trust and discuss strategies that can help control for some risk factors.

Finally, the provider would re-evaluate throughout the procedure by continuously monitoring the patient’s anxiety and vital signs. The provider should also be ready to adjust pain management or employ anxiety-reduction techniques.

Final Thoughts

Reviewing the risk assessment matrix can be an effective way to nonjudgmentally discuss a patient’s unique risk factors and provide a complete understanding of the planned treatment or procedure. It conveys to the patient that, as the provider, you are taking their health seriously when considering treatment options and can be a means to build patient rapport and trust. This approach mirrors risk communication strategies long employed in military operational planning, where transparency and structured risk evaluation are essential to maintaining mission readiness and unit cohesion.

Biting midges, commonly known as no-see-ums, are true flies (order Diptera) and members of the Ceratopogonidae family. Regionally, they are known as punkies in the Northeast, pinyon gnats in the Southwest, moose flies in Canada, and sand gnats in Georgia, among other names.¹ There are 6206 species found worldwide except for Antarctica.² The 3 genera of greatest importance to human and livestock health in the United States are Culicoides, Leptoconops, and Forcipomyia.¹ Forty-seven species of the genus Culicoides are known to be present in Florida.³ Species belonging to the genus Leptoconops also are present in coastal areas of southeast Florida as well as in the tropics, subtropics, and Caribbean.³ In the United States, biting midges primarily are a nuisance; the major medical issue associated with Culicoides insects are allergic reactions to their bites. Even though no-see-ums are not known to transmit disease in humans, they have an impact on other animal species in the United States as biting pests and vectors of disease-causing pathogens.¹ Biting midges pose quite a nuisance for the proper enjoyment of outdoor spaces in the southeastern United States.

Characteristics

Morphologically, no-see-ums are gray flies measuring 1 to 3 mm in length (eFigure 1). Adults have 2 wings with distinctive patterns, large compound eyes, a thorax that extends slightly over the head, an abdomen with 9 segments, and antennae with 15 segments (eFigure 2).^1,3,4 Females have modified mouth parts including mandibles that lacerate the skin during feeding, which is mainly on blood from vertebrate hosts (primarily mammals but also birds, reptiles, and amphibians).^1,4 They also can feed on invertebrate hosts. Both male and female no-see-ums feed on nectar, but adult females require a blood meal to develop their eggs.² Their life cycle progresses in stages from egg to larva to pupa to adult. Larval habitats include salt marshes, swamps, shores of streams and ponds, water-holding plants, rotting fruit, and saturated wood- and manure-enriched soil. Adults can live 2 to 7 weeks. They are weak fliers, particularly in windy conditions.¹

In Florida, no-see-ums are more active during the rainy months of May to October but are active year-round in the southeastern United States and the Gulf Coast from Florida to West Texas. They are active throughout the United States in the warmer months of June and July.⁵ Their peak feeding activity occurs at dawn and dusk, but different species of biting midges such as Leptoconops and Culicoides also can feed during daylight hours and at night, respectively.^1,6,7

Case Report

One of the authors (M.J.S.), a healthy 54-year-old man with no remarkable medical history or current use of medications, documented the natural progression of a no-see-um bite by sitting in an outdoor Florida space at 8:00 am armed with a dermatoscope and a smartphone camera. The initial sensation of the bite felt like a sting that progressed over a few minutes to itchiness; however, the culprit was not readily identifiable. Upon closer inspection, pinpoint black dots could be correlated with the location of discomfort on the exposed upper extremities. Upon dermoscopic examination, 2 biting midges were identified as well as multiple wheals at the bite sites, and they seemed unbothered by the polarized light of the dermatoscope while feeding (eFigure 3). They flew away after a few minutes of feeding. The site of the bite wound was readily identifiable on dermoscopy as a wheal with a pinpoint red dot at the center (eFigure 4). The wheal started to form during the act of feeding and lasted up to 2 hours before fading (eFigure 5). The itch quickly resolved within the hour if hydrocortisone 1% was used. If untreated and scratched, itching rarely could last longer than a day.

Clinical Manifestations

Although no-see-ums are not known to transmit disease in the United States, they are important biting pests that can affect tourism and prevent enjoyment of outdoor spaces and activities.² The bite reactions on the host can range from wheal-like lesions to papules measuring 2 to 3 mm (at times with overlying vesicles) to nodules up to 1 cm in diameter.⁸ In our reported case, the small wheals disappeared within hours, but pruritic papules have been described to last from weeks to months. Published histopathologic correlation of biopsied indurated papules within 3 days of bite occurrence have revealed a superficial infiltrate composed of lymphocytes and histiocytes, while eosinophils were found in the deeper dermis and subcutaneous fat. Within 2 weeks, as the lesions aged, the infiltrate contained a smaller percentage of eosinophils and predominantly was present in only the superficial dermis.⁸ Delayed-type hypersensitivity reactions including pustules and bullous lesions also have been described.^9,10 Host immune reaction to the saliva introduced during the bite dictates the severity of the response, and lesions may become secondarily infected due to scratching.¹¹

Management Recommendations

Management consists of cleaning the bite site with soap and water to prevent infection, applying cold compresses or ice packs to relieve the intense itch, and avoiding scratching.¹¹ Application of over-the-counter calamine lotion or hydrocortisone cream can relieve itch, and mid- to high-potency topical corticosteroids also can be prescribed for 1 to 2 weeks for more intense bite reactions in conjunction with oral antihistamines. Topical or oral antibiotics may be indicated if redness and swelling progress at the bite site or if breaks in the skin become secondarily infected.

Final Thoughts

Because of the wide-ranging habitats of no-see-ums, eradication programs using insecticides have been inefficient or environmentally suboptimal. Emptying all standing water in outdoor spaces will reduce the number of no-see-ums. Avoidance of the outdoors at dawn and dusk when no-see-ums are most active is helpful, as well as protecting exposed skin by wearing long-sleeved shirts and long pants when outside. Insect repellents containing DEET (N-N-diethyl-meta-toluamide) or picaridin can offer additional protection on the remaining exposed skin. Oil of lemon eucalyptus, or active compound p-menthane-3,8-diol, has been shown to be effective against no-see-ums. Use of DEET should be avoided in children younger than 2 years and p-menthane-3,8-diol in those younger than 3 years. Picaridin is safe for use in children.¹² Citronella oil is ineffective. Installing window and patio screens with a mesh size less than 16 can prevent no-see-ums from passing through the netting but will restrict air flow.³ Turning off porch lights also is helpful, as no-see-ums are attracted to light sources.⁶ Since no-see-ums are weak flyers, setting ceiling or window fans at high speeds can minimize exposure; similarly, being outdoors on a windy day may decrease the likelihood of being bitten. Ultimately, the best remedy for a bite is to prevent them from happening.

Biting midges, commonly known as no-see-ums, are true flies (order Diptera) and members of the Ceratopogonidae family. Regionally, they are known as punkies in the Northeast, pinyon gnats in the Southwest, moose flies in Canada, and sand gnats in Georgia, among other names.¹ There are 6206 species found worldwide except for Antarctica.² The 3 genera of greatest importance to human and livestock health in the United States are Culicoides, Leptoconops, and Forcipomyia.¹ Forty-seven species of the genus Culicoides are known to be present in Florida.³ Species belonging to the genus Leptoconops also are present in coastal areas of southeast Florida as well as in the tropics, subtropics, and Caribbean.³ In the United States, biting midges primarily are a nuisance; the major medical issue associated with Culicoides insects are allergic reactions to their bites. Even though no-see-ums are not known to transmit disease in humans, they have an impact on other animal species in the United States as biting pests and vectors of disease-causing pathogens.¹ Biting midges pose quite a nuisance for the proper enjoyment of outdoor spaces in the southeastern United States.

Characteristics

Morphologically, no-see-ums are gray flies measuring 1 to 3 mm in length (eFigure 1). Adults have 2 wings with distinctive patterns, large compound eyes, a thorax that extends slightly over the head, an abdomen with 9 segments, and antennae with 15 segments (eFigure 2).^1,3,4 Females have modified mouth parts including mandibles that lacerate the skin during feeding, which is mainly on blood from vertebrate hosts (primarily mammals but also birds, reptiles, and amphibians).^1,4 They also can feed on invertebrate hosts. Both male and female no-see-ums feed on nectar, but adult females require a blood meal to develop their eggs.² Their life cycle progresses in stages from egg to larva to pupa to adult. Larval habitats include salt marshes, swamps, shores of streams and ponds, water-holding plants, rotting fruit, and saturated wood- and manure-enriched soil. Adults can live 2 to 7 weeks. They are weak fliers, particularly in windy conditions.¹

In Florida, no-see-ums are more active during the rainy months of May to October but are active year-round in the southeastern United States and the Gulf Coast from Florida to West Texas. They are active throughout the United States in the warmer months of June and July.⁵ Their peak feeding activity occurs at dawn and dusk, but different species of biting midges such as Leptoconops and Culicoides also can feed during daylight hours and at night, respectively.^1,6,7

Case Report

One of the authors (M.J.S.), a healthy 54-year-old man with no remarkable medical history or current use of medications, documented the natural progression of a no-see-um bite by sitting in an outdoor Florida space at 8:00 am armed with a dermatoscope and a smartphone camera. The initial sensation of the bite felt like a sting that progressed over a few minutes to itchiness; however, the culprit was not readily identifiable. Upon closer inspection, pinpoint black dots could be correlated with the location of discomfort on the exposed upper extremities. Upon dermoscopic examination, 2 biting midges were identified as well as multiple wheals at the bite sites, and they seemed unbothered by the polarized light of the dermatoscope while feeding (eFigure 3). They flew away after a few minutes of feeding. The site of the bite wound was readily identifiable on dermoscopy as a wheal with a pinpoint red dot at the center (eFigure 4). The wheal started to form during the act of feeding and lasted up to 2 hours before fading (eFigure 5). The itch quickly resolved within the hour if hydrocortisone 1% was used. If untreated and scratched, itching rarely could last longer than a day.

Clinical Manifestations

Although no-see-ums are not known to transmit disease in the United States, they are important biting pests that can affect tourism and prevent enjoyment of outdoor spaces and activities.² The bite reactions on the host can range from wheal-like lesions to papules measuring 2 to 3 mm (at times with overlying vesicles) to nodules up to 1 cm in diameter.⁸ In our reported case, the small wheals disappeared within hours, but pruritic papules have been described to last from weeks to months. Published histopathologic correlation of biopsied indurated papules within 3 days of bite occurrence have revealed a superficial infiltrate composed of lymphocytes and histiocytes, while eosinophils were found in the deeper dermis and subcutaneous fat. Within 2 weeks, as the lesions aged, the infiltrate contained a smaller percentage of eosinophils and predominantly was present in only the superficial dermis.⁸ Delayed-type hypersensitivity reactions including pustules and bullous lesions also have been described.^9,10 Host immune reaction to the saliva introduced during the bite dictates the severity of the response, and lesions may become secondarily infected due to scratching.¹¹

Management Recommendations

Management consists of cleaning the bite site with soap and water to prevent infection, applying cold compresses or ice packs to relieve the intense itch, and avoiding scratching.¹¹ Application of over-the-counter calamine lotion or hydrocortisone cream can relieve itch, and mid- to high-potency topical corticosteroids also can be prescribed for 1 to 2 weeks for more intense bite reactions in conjunction with oral antihistamines. Topical or oral antibiotics may be indicated if redness and swelling progress at the bite site or if breaks in the skin become secondarily infected.

Final Thoughts

Because of the wide-ranging habitats of no-see-ums, eradication programs using insecticides have been inefficient or environmentally suboptimal. Emptying all standing water in outdoor spaces will reduce the number of no-see-ums. Avoidance of the outdoors at dawn and dusk when no-see-ums are most active is helpful, as well as protecting exposed skin by wearing long-sleeved shirts and long pants when outside. Insect repellents containing DEET (N-N-diethyl-meta-toluamide) or picaridin can offer additional protection on the remaining exposed skin. Oil of lemon eucalyptus, or active compound p-menthane-3,8-diol, has been shown to be effective against no-see-ums. Use of DEET should be avoided in children younger than 2 years and p-menthane-3,8-diol in those younger than 3 years. Picaridin is safe for use in children.¹² Citronella oil is ineffective. Installing window and patio screens with a mesh size less than 16 can prevent no-see-ums from passing through the netting but will restrict air flow.³ Turning off porch lights also is helpful, as no-see-ums are attracted to light sources.⁶ Since no-see-ums are weak flyers, setting ceiling or window fans at high speeds can minimize exposure; similarly, being outdoors on a windy day may decrease the likelihood of being bitten. Ultimately, the best remedy for a bite is to prevent them from happening.

Biting midges, commonly known as no-see-ums, are true flies (order Diptera) and members of the Ceratopogonidae family. Regionally, they are known as punkies in the Northeast, pinyon gnats in the Southwest, moose flies in Canada, and sand gnats in Georgia, among other names.¹ There are 6206 species found worldwide except for Antarctica.² The 3 genera of greatest importance to human and livestock health in the United States are Culicoides, Leptoconops, and Forcipomyia.¹ Forty-seven species of the genus Culicoides are known to be present in Florida.³ Species belonging to the genus Leptoconops also are present in coastal areas of southeast Florida as well as in the tropics, subtropics, and Caribbean.³ In the United States, biting midges primarily are a nuisance; the major medical issue associated with Culicoides insects are allergic reactions to their bites. Even though no-see-ums are not known to transmit disease in humans, they have an impact on other animal species in the United States as biting pests and vectors of disease-causing pathogens.¹ Biting midges pose quite a nuisance for the proper enjoyment of outdoor spaces in the southeastern United States.

Characteristics

Morphologically, no-see-ums are gray flies measuring 1 to 3 mm in length (eFigure 1). Adults have 2 wings with distinctive patterns, large compound eyes, a thorax that extends slightly over the head, an abdomen with 9 segments, and antennae with 15 segments (eFigure 2).^1,3,4 Females have modified mouth parts including mandibles that lacerate the skin during feeding, which is mainly on blood from vertebrate hosts (primarily mammals but also birds, reptiles, and amphibians).^1,4 They also can feed on invertebrate hosts. Both male and female no-see-ums feed on nectar, but adult females require a blood meal to develop their eggs.² Their life cycle progresses in stages from egg to larva to pupa to adult. Larval habitats include salt marshes, swamps, shores of streams and ponds, water-holding plants, rotting fruit, and saturated wood- and manure-enriched soil. Adults can live 2 to 7 weeks. They are weak fliers, particularly in windy conditions.¹

In Florida, no-see-ums are more active during the rainy months of May to October but are active year-round in the southeastern United States and the Gulf Coast from Florida to West Texas. They are active throughout the United States in the warmer months of June and July.⁵ Their peak feeding activity occurs at dawn and dusk, but different species of biting midges such as Leptoconops and Culicoides also can feed during daylight hours and at night, respectively.^1,6,7

Case Report

One of the authors (M.J.S.), a healthy 54-year-old man with no remarkable medical history or current use of medications, documented the natural progression of a no-see-um bite by sitting in an outdoor Florida space at 8:00 am armed with a dermatoscope and a smartphone camera. The initial sensation of the bite felt like a sting that progressed over a few minutes to itchiness; however, the culprit was not readily identifiable. Upon closer inspection, pinpoint black dots could be correlated with the location of discomfort on the exposed upper extremities. Upon dermoscopic examination, 2 biting midges were identified as well as multiple wheals at the bite sites, and they seemed unbothered by the polarized light of the dermatoscope while feeding (eFigure 3). They flew away after a few minutes of feeding. The site of the bite wound was readily identifiable on dermoscopy as a wheal with a pinpoint red dot at the center (eFigure 4). The wheal started to form during the act of feeding and lasted up to 2 hours before fading (eFigure 5). The itch quickly resolved within the hour if hydrocortisone 1% was used. If untreated and scratched, itching rarely could last longer than a day.

Clinical Manifestations

Although no-see-ums are not known to transmit disease in the United States, they are important biting pests that can affect tourism and prevent enjoyment of outdoor spaces and activities.² The bite reactions on the host can range from wheal-like lesions to papules measuring 2 to 3 mm (at times with overlying vesicles) to nodules up to 1 cm in diameter.⁸ In our reported case, the small wheals disappeared within hours, but pruritic papules have been described to last from weeks to months. Published histopathologic correlation of biopsied indurated papules within 3 days of bite occurrence have revealed a superficial infiltrate composed of lymphocytes and histiocytes, while eosinophils were found in the deeper dermis and subcutaneous fat. Within 2 weeks, as the lesions aged, the infiltrate contained a smaller percentage of eosinophils and predominantly was present in only the superficial dermis.⁸ Delayed-type hypersensitivity reactions including pustules and bullous lesions also have been described.^9,10 Host immune reaction to the saliva introduced during the bite dictates the severity of the response, and lesions may become secondarily infected due to scratching.¹¹

Management Recommendations

Management consists of cleaning the bite site with soap and water to prevent infection, applying cold compresses or ice packs to relieve the intense itch, and avoiding scratching.¹¹ Application of over-the-counter calamine lotion or hydrocortisone cream can relieve itch, and mid- to high-potency topical corticosteroids also can be prescribed for 1 to 2 weeks for more intense bite reactions in conjunction with oral antihistamines. Topical or oral antibiotics may be indicated if redness and swelling progress at the bite site or if breaks in the skin become secondarily infected.

Final Thoughts

Because of the wide-ranging habitats of no-see-ums, eradication programs using insecticides have been inefficient or environmentally suboptimal. Emptying all standing water in outdoor spaces will reduce the number of no-see-ums. Avoidance of the outdoors at dawn and dusk when no-see-ums are most active is helpful, as well as protecting exposed skin by wearing long-sleeved shirts and long pants when outside. Insect repellents containing DEET (N-N-diethyl-meta-toluamide) or picaridin can offer additional protection on the remaining exposed skin. Oil of lemon eucalyptus, or active compound p-menthane-3,8-diol, has been shown to be effective against no-see-ums. Use of DEET should be avoided in children younger than 2 years and p-menthane-3,8-diol in those younger than 3 years. Picaridin is safe for use in children.¹² Citronella oil is ineffective. Installing window and patio screens with a mesh size less than 16 can prevent no-see-ums from passing through the netting but will restrict air flow.³ Turning off porch lights also is helpful, as no-see-ums are attracted to light sources.⁶ Since no-see-ums are weak flyers, setting ceiling or window fans at high speeds can minimize exposure; similarly, being outdoors on a windy day may decrease the likelihood of being bitten. Ultimately, the best remedy for a bite is to prevent them from happening.

Practice Gap

Hyperhidrosis poses a considerable challenge for many amputees who use prosthetic devices, particularly at the interface between the residual limb and the prosthetic socket. The enclosed environment of the socket often leads to excessive sweating, which can compromise suction fit and increase the risk for skin chafing, irritation, and slippage. Persistent moisture also promotes bacterial and fungal growth, raising the likelihood of infections and foul odors within the socket. Research has shown that skin complications are highly prevalent among amputees, affecting up to 73.9% of this population in the United States.¹ Commonly reported complications include wounds, abscesses, and blisters, many of which can be triggered or worsened by hyperhidrosis.² Current treatment options for residual limb sweating include topical antiperspirants, botulinum toxin (BTX) injections, iontophoresis, and liner-liner socks.

While BTX commonly is used to treat hyperhidrosis in areas such as the palms and axillae, it typically is not considered as a first-line therapy for residual limb sweating; however, both BTX type A and type B have shown safety and effectiveness in managing hyperhidrosis in amputees, enhancing prosthetic use, and improving overall quality of life.³ Despite these benefits, BTX remains relatively underutilized for residual limb sweating, particularly among dermatologists who may not routinely treat individuals with acquired limb loss. This presents an opportunity for dermatologists to expand their scope and address the unique needs of amputees. We propose a technique for administering BTX injections to treat residual limb hyperhidrosis.

Tools and Techniques

A 64-year-old man initially presented to our dermatology clinic after undergoing an above-the-knee amputation of the left leg 1 year prior. The amputation had been performed due to chronic prosthetic joint infections with Escherichia coli. He reported persistent sweating of the residual limb, which severely limited his use of a prosthesis and led to frequent falls.

During the initial visit, treatment options for primary hyperhidrosis including topical and injectable therapies were discussed. Due to a fear of needles, the patient chose topical treatment, with the option to pursue BTX injections later if better control was needed. An aluminum chloride hexahydrate prosthetic antiperspirant was prescribed for nightly application on the anterior and posterior residual limb along with an over-the-counter prosthetic antiperspirant simultaneously. Although the over-the-counter prosthetic antiperspirant provided partial relief, the symptoms persisted, preventing the patient from returning to work. Unfortunately, the prescription antiperspirant was prohibitively expensive and not covered by the patient’s insurance. As a result, BTX injections were initiated at 1-month follow-up.

Botulinum toxin injections were administered in a grid-like pattern across the surface area where the residual limb made contact with the prosthetic. Using a surgical marker, the patient assisted the medical team in identifying the areas where sweating occurred most frequently. The area was divided into 4 equal sections, with each section treated per weekly interval sequentially over 4 weeks. The targeted areas included the left anterior (extending from the anterior tensor fasciae latae band to the lateral thigh) and left posterior residual limb (Figure 1 and eFigure 1, respectively).

The treated section was cleaned with an alcohol wipe prior to each injection, and 50 units of BTX (diluted to 2.5 units per 0.1 mL in bacteriostatic saline) were injected intradermally into each section (Figure 2 and eFigure 2). The injections were administered in rows, with the needle inserted at evenly spaced intervals approximately 1 inch apart. A total of 100 units were administered per section at each weekly appointment. The patient tolerated the procedure well, and no complications were observed.

Practice Implications

This staged approach to administering BTX ensures even distribution of the injections, optimizes hyperhidrosis control, minimizes the risk for complications, and allows for precise targeting of the affected areas to maximize therapeutic benefit. Following the initial procedure, our patient was scheduled for follow-ups approximately every 3 to 4 months starting from the first set of injections for each area. Over 9 months, the patient successfully completed 3 treatment sessions using this method. The patient reported improved quality of life after starting the BTX injections.

After evaluating the initial treatment outcomes with 100 units per section, the dosage was increased to 200 units per section to reduce the number of visits from 4 every 3 months to cover the entire area to 2 visits every 3 months. This adjustment aimed to optimize results and better manage the patient’s ongoing symptoms. At about 1 to 2 weeks after beginning treatment, the patient noticed decreased sweating and discomfort during his daily activities and reduced friction with his prosthetic leg. No adverse effects were noted with the increased dosage during a clinical visit. 

Our case highlights the importance of ensuring equitable access to hyperhidrosis treatment. Dermatologists should prioritize patient-centered care by factoring in financial constraints when recommending therapies. In this patient’s case, offering a range of options including over-the-counter antiperspirants and prescription treatments allowed for a management plan tailored to his individual needs and circumstances.

DaxibotulinumtoxinA, known for its longer duration of action compared to other BTX formulations, presents a promising alternative for treating hyperhidrosis.⁴ However, a gap in care emerged for our patient when prescription antiperspirant was not covered by his insurance, and daxibotulinumtoxinA, which could have offered a more durable solution, was not yet available at our clinic for hyperhidrosis management. Expanding insurance coverage for effective prescription treatments and improving access to newer treatment options are crucial for enhancing patient outcomes and ensuring more equitable care.

Focusing dermatologic care on amputees presents distinct challenges and opportunities for improving their care and decreasing discomfort. Amputees, particularly those with residual limb hyperhidrosis, often experience additional discomfort and difficulty while using prosthetics, as excessive sweating can interfere with fit and function.^5,6 Dermatologists should proactively address these specific needs by tailoring treatment accordingly. Incorporating targeted therapies, such as BTX injections, in addition to education on lifestyle modifications and managing treatment expectations, ensures comprehensive care that enhances both quality of life and functional outcomes. Engaging patients in discussions about all available options, including emerging therapies, is essential for improving care for this underserved population.

Practice Gap

Hyperhidrosis poses a considerable challenge for many amputees who use prosthetic devices, particularly at the interface between the residual limb and the prosthetic socket. The enclosed environment of the socket often leads to excessive sweating, which can compromise suction fit and increase the risk for skin chafing, irritation, and slippage. Persistent moisture also promotes bacterial and fungal growth, raising the likelihood of infections and foul odors within the socket. Research has shown that skin complications are highly prevalent among amputees, affecting up to 73.9% of this population in the United States.¹ Commonly reported complications include wounds, abscesses, and blisters, many of which can be triggered or worsened by hyperhidrosis.² Current treatment options for residual limb sweating include topical antiperspirants, botulinum toxin (BTX) injections, iontophoresis, and liner-liner socks.

While BTX commonly is used to treat hyperhidrosis in areas such as the palms and axillae, it typically is not considered as a first-line therapy for residual limb sweating; however, both BTX type A and type B have shown safety and effectiveness in managing hyperhidrosis in amputees, enhancing prosthetic use, and improving overall quality of life.³ Despite these benefits, BTX remains relatively underutilized for residual limb sweating, particularly among dermatologists who may not routinely treat individuals with acquired limb loss. This presents an opportunity for dermatologists to expand their scope and address the unique needs of amputees. We propose a technique for administering BTX injections to treat residual limb hyperhidrosis.

Tools and Techniques

A 64-year-old man initially presented to our dermatology clinic after undergoing an above-the-knee amputation of the left leg 1 year prior. The amputation had been performed due to chronic prosthetic joint infections with Escherichia coli. He reported persistent sweating of the residual limb, which severely limited his use of a prosthesis and led to frequent falls.

During the initial visit, treatment options for primary hyperhidrosis including topical and injectable therapies were discussed. Due to a fear of needles, the patient chose topical treatment, with the option to pursue BTX injections later if better control was needed. An aluminum chloride hexahydrate prosthetic antiperspirant was prescribed for nightly application on the anterior and posterior residual limb along with an over-the-counter prosthetic antiperspirant simultaneously. Although the over-the-counter prosthetic antiperspirant provided partial relief, the symptoms persisted, preventing the patient from returning to work. Unfortunately, the prescription antiperspirant was prohibitively expensive and not covered by the patient’s insurance. As a result, BTX injections were initiated at 1-month follow-up.

Botulinum toxin injections were administered in a grid-like pattern across the surface area where the residual limb made contact with the prosthetic. Using a surgical marker, the patient assisted the medical team in identifying the areas where sweating occurred most frequently. The area was divided into 4 equal sections, with each section treated per weekly interval sequentially over 4 weeks. The targeted areas included the left anterior (extending from the anterior tensor fasciae latae band to the lateral thigh) and left posterior residual limb (Figure 1 and eFigure 1, respectively).

The treated section was cleaned with an alcohol wipe prior to each injection, and 50 units of BTX (diluted to 2.5 units per 0.1 mL in bacteriostatic saline) were injected intradermally into each section (Figure 2 and eFigure 2). The injections were administered in rows, with the needle inserted at evenly spaced intervals approximately 1 inch apart. A total of 100 units were administered per section at each weekly appointment. The patient tolerated the procedure well, and no complications were observed.

Practice Implications

This staged approach to administering BTX ensures even distribution of the injections, optimizes hyperhidrosis control, minimizes the risk for complications, and allows for precise targeting of the affected areas to maximize therapeutic benefit. Following the initial procedure, our patient was scheduled for follow-ups approximately every 3 to 4 months starting from the first set of injections for each area. Over 9 months, the patient successfully completed 3 treatment sessions using this method. The patient reported improved quality of life after starting the BTX injections.

After evaluating the initial treatment outcomes with 100 units per section, the dosage was increased to 200 units per section to reduce the number of visits from 4 every 3 months to cover the entire area to 2 visits every 3 months. This adjustment aimed to optimize results and better manage the patient’s ongoing symptoms. At about 1 to 2 weeks after beginning treatment, the patient noticed decreased sweating and discomfort during his daily activities and reduced friction with his prosthetic leg. No adverse effects were noted with the increased dosage during a clinical visit. 

Our case highlights the importance of ensuring equitable access to hyperhidrosis treatment. Dermatologists should prioritize patient-centered care by factoring in financial constraints when recommending therapies. In this patient’s case, offering a range of options including over-the-counter antiperspirants and prescription treatments allowed for a management plan tailored to his individual needs and circumstances.

DaxibotulinumtoxinA, known for its longer duration of action compared to other BTX formulations, presents a promising alternative for treating hyperhidrosis.⁴ However, a gap in care emerged for our patient when prescription antiperspirant was not covered by his insurance, and daxibotulinumtoxinA, which could have offered a more durable solution, was not yet available at our clinic for hyperhidrosis management. Expanding insurance coverage for effective prescription treatments and improving access to newer treatment options are crucial for enhancing patient outcomes and ensuring more equitable care.

Focusing dermatologic care on amputees presents distinct challenges and opportunities for improving their care and decreasing discomfort. Amputees, particularly those with residual limb hyperhidrosis, often experience additional discomfort and difficulty while using prosthetics, as excessive sweating can interfere with fit and function.^5,6 Dermatologists should proactively address these specific needs by tailoring treatment accordingly. Incorporating targeted therapies, such as BTX injections, in addition to education on lifestyle modifications and managing treatment expectations, ensures comprehensive care that enhances both quality of life and functional outcomes. Engaging patients in discussions about all available options, including emerging therapies, is essential for improving care for this underserved population.

Practice Gap

Hyperhidrosis poses a considerable challenge for many amputees who use prosthetic devices, particularly at the interface between the residual limb and the prosthetic socket. The enclosed environment of the socket often leads to excessive sweating, which can compromise suction fit and increase the risk for skin chafing, irritation, and slippage. Persistent moisture also promotes bacterial and fungal growth, raising the likelihood of infections and foul odors within the socket. Research has shown that skin complications are highly prevalent among amputees, affecting up to 73.9% of this population in the United States.¹ Commonly reported complications include wounds, abscesses, and blisters, many of which can be triggered or worsened by hyperhidrosis.² Current treatment options for residual limb sweating include topical antiperspirants, botulinum toxin (BTX) injections, iontophoresis, and liner-liner socks.

While BTX commonly is used to treat hyperhidrosis in areas such as the palms and axillae, it typically is not considered as a first-line therapy for residual limb sweating; however, both BTX type A and type B have shown safety and effectiveness in managing hyperhidrosis in amputees, enhancing prosthetic use, and improving overall quality of life.³ Despite these benefits, BTX remains relatively underutilized for residual limb sweating, particularly among dermatologists who may not routinely treat individuals with acquired limb loss. This presents an opportunity for dermatologists to expand their scope and address the unique needs of amputees. We propose a technique for administering BTX injections to treat residual limb hyperhidrosis.

Tools and Techniques

A 64-year-old man initially presented to our dermatology clinic after undergoing an above-the-knee amputation of the left leg 1 year prior. The amputation had been performed due to chronic prosthetic joint infections with Escherichia coli. He reported persistent sweating of the residual limb, which severely limited his use of a prosthesis and led to frequent falls.

During the initial visit, treatment options for primary hyperhidrosis including topical and injectable therapies were discussed. Due to a fear of needles, the patient chose topical treatment, with the option to pursue BTX injections later if better control was needed. An aluminum chloride hexahydrate prosthetic antiperspirant was prescribed for nightly application on the anterior and posterior residual limb along with an over-the-counter prosthetic antiperspirant simultaneously. Although the over-the-counter prosthetic antiperspirant provided partial relief, the symptoms persisted, preventing the patient from returning to work. Unfortunately, the prescription antiperspirant was prohibitively expensive and not covered by the patient’s insurance. As a result, BTX injections were initiated at 1-month follow-up.

Botulinum toxin injections were administered in a grid-like pattern across the surface area where the residual limb made contact with the prosthetic. Using a surgical marker, the patient assisted the medical team in identifying the areas where sweating occurred most frequently. The area was divided into 4 equal sections, with each section treated per weekly interval sequentially over 4 weeks. The targeted areas included the left anterior (extending from the anterior tensor fasciae latae band to the lateral thigh) and left posterior residual limb (Figure 1 and eFigure 1, respectively).

The treated section was cleaned with an alcohol wipe prior to each injection, and 50 units of BTX (diluted to 2.5 units per 0.1 mL in bacteriostatic saline) were injected intradermally into each section (Figure 2 and eFigure 2). The injections were administered in rows, with the needle inserted at evenly spaced intervals approximately 1 inch apart. A total of 100 units were administered per section at each weekly appointment. The patient tolerated the procedure well, and no complications were observed.

Practice Implications

This staged approach to administering BTX ensures even distribution of the injections, optimizes hyperhidrosis control, minimizes the risk for complications, and allows for precise targeting of the affected areas to maximize therapeutic benefit. Following the initial procedure, our patient was scheduled for follow-ups approximately every 3 to 4 months starting from the first set of injections for each area. Over 9 months, the patient successfully completed 3 treatment sessions using this method. The patient reported improved quality of life after starting the BTX injections.

After evaluating the initial treatment outcomes with 100 units per section, the dosage was increased to 200 units per section to reduce the number of visits from 4 every 3 months to cover the entire area to 2 visits every 3 months. This adjustment aimed to optimize results and better manage the patient’s ongoing symptoms. At about 1 to 2 weeks after beginning treatment, the patient noticed decreased sweating and discomfort during his daily activities and reduced friction with his prosthetic leg. No adverse effects were noted with the increased dosage during a clinical visit. 

Our case highlights the importance of ensuring equitable access to hyperhidrosis treatment. Dermatologists should prioritize patient-centered care by factoring in financial constraints when recommending therapies. In this patient’s case, offering a range of options including over-the-counter antiperspirants and prescription treatments allowed for a management plan tailored to his individual needs and circumstances.

DaxibotulinumtoxinA, known for its longer duration of action compared to other BTX formulations, presents a promising alternative for treating hyperhidrosis.⁴ However, a gap in care emerged for our patient when prescription antiperspirant was not covered by his insurance, and daxibotulinumtoxinA, which could have offered a more durable solution, was not yet available at our clinic for hyperhidrosis management. Expanding insurance coverage for effective prescription treatments and improving access to newer treatment options are crucial for enhancing patient outcomes and ensuring more equitable care.

Focusing dermatologic care on amputees presents distinct challenges and opportunities for improving their care and decreasing discomfort. Amputees, particularly those with residual limb hyperhidrosis, often experience additional discomfort and difficulty while using prosthetics, as excessive sweating can interfere with fit and function.^5,6 Dermatologists should proactively address these specific needs by tailoring treatment accordingly. Incorporating targeted therapies, such as BTX injections, in addition to education on lifestyle modifications and managing treatment expectations, ensures comprehensive care that enhances both quality of life and functional outcomes. Engaging patients in discussions about all available options, including emerging therapies, is essential for improving care for this underserved population.

Emergency departments (EDs) and immediate care (IC) facilities often do not have prompt dermatologic care available for triage and treatment. Many EDs do not have staff dermatologists on call, instead relying on input from other specialists or quick outpatient dermatology appointments. It can be challenging to obtain a prompt appointment with a board-certified dermatologist, which is preferred for complex cases such as severe drug reactions or infection. In the United States, there are few well-established IC centers equipped to address dermatologic needs. The orthopedic specialty has modeled a concept that has led to the establishment of orthopedic urgent care/IC in many larger institutions,¹ and many private practice clinics serve their communities as well. We present a rationale for why a similar IC concept for dermatology would be beneficial, particularly within a large institution or health system.

Dermatology Consultation Changes Disease Management

There is diagnostic and therapeutic utility in dermatology evaluation. In a prospective study of 591 patients who were either hospitalized or evaluated in an ED/urgent care setting, treatment was changed in more than 60% of cases when dermatology consultation was utilized.² In another prospective review of 691 cases on an inpatient service, dermatology consultation resulted in treatment changes more than 80% of the time.³

Cellulitis has been a particularly well-studied diagnosis. Dermatologists often change the diagnosis of cellulitis in the hospital setting and reduce antibiotic exposure. In a prospective cohort study of 116 patients, 33.6% had their diagnosis of cellulitis changed to pseudocellulitis following evaluation by the dermatologist; of 34 patients who had started antibiotic therapy, 82.4% were recommended to discontinue the treatment, and all 39 patients with pseudocellulitis had a proven stable clinical course at 1-month follow-up.⁴ In another trial, 175 patients with presumed cellulitis were given standard management (provided by the medicine inpatient team) either alone or with the addition of dermatology consultation. Duration of antibiotic treatment (including intravenous therapy) was reduced when dermatology was consulted. Two weeks after discharge, patients who had dermatology consultations demonstrated greater clinical improvement.⁵

Improving ED and IC Access to Dermatology

Emergency department and IC teams across the United States work tirelessly to meet the demands of patients presenting with medically urgent conditions. In a study examining 861 ED cases, dermatology made up only 9.5% of specialist consultations, and in the opinion of the on-call dermatology resident, 51.0% (439/861) of cases warranted ED-level care.⁶

Data from the 2021 National Hospital Ambulatory Medical Care Survey showed that the mean wait time to see a physician, nurse, or physician assistant in an ED was 37.5 minutes, but wait times could range from less than 15 minutes to more than 6 hours.⁷ According to a study of 35,849 ED visits at nonfederal hospitals in the United States, only 47.7% of EDs admitted more than 90% of their patients within 6 hours.⁸ Moreover, perceived wait times in the ED have been shown to greatly impact patient satisfaction. Two predictors of perceived wait time include appropriate assessment of emergency level and the feeling of being forgotten.⁹ In a study of 2377 ED visits with primary dermatologic diagnoses, only 5.5% led to admission.¹⁰ This suggests many patients who come to the ED for dermatologic needs do not require inpatient hospital care. In these cases, patients with primary dermatologic concerns may experience longer ED wait times, as higher acuity or emergency cases take precedence. Studies also have shown that more vulnerable populations are utilizing ED visits most for primary dermatologic concerns.^10,11 This includes individuals of lower income and/or those with Medicaid/Medicare or those without insurance.¹¹ Predictors of high ED use for dermatologic concerns include prior frequent use of the ED (for nondermatologic concerns) instead of outpatient care, income below the poverty level, and lack of insurance; older individuals (>65 years) also were found to use the ED more frequently for dermatologic concerns when compared to younger individuals.¹⁰

Importantly, there is a great need for urgent dermatology consultation for pediatric patients. A single-institution study showed that over a 36-month period, there were 347 pediatric dermatology consultations from the pediatric ED mostly for children aged 0 days to 5 years; nearly half of these consultations required outpatient clinic follow-up.¹² However, dermatology outpatient follow-up can be difficult to obtain, especially for vulnerable groups. In a study of 611 dermatology clinics, patients with Medicaid were shown to have longer wait times and less success in obtaining dermatology appointments compared to those with Medicare or private insurance.¹³ Only about 30% of private dermatology practices accept Medicaid patients, likely pushing these patients toward utilization of emergency services for dermatologic concerns.^13,14

There is a clear role for a dermatology IC in our health care system, and the concept already has been identified and trialed in several institutions. At Oregon Health and Science University (Portland, Oregon), a retrospective chart review of patients with diagnoses of Morgellons disease and neurotic excoriations seen in dermatology urgent care between 2018 and 2020 showed an 88% decrease in annual rates of health care visits and a 77% decrease in ED visits after dermatology services were engaged compared to before the opening of the dermatology urgent care.¹⁵ Another study showed that uninsured or self-pay patients were more than 14 times more likely to access dermatology urgent care than to schedule a routine clinic appointment, suggesting that there is a barrier to making outpatient dermatologic appointments for uninsured patients. An urgent access model may facilitate the ability of underinsured patients to access care.¹⁶

Improving Dermatology Access for Other Specialties

Needs for dermatologic care are encountered in many other specialties. Having direct access to immediate dermatologic treatment is best for patients and may avoid inpatient care and trips to the ED for consultation access. Ideally, a dermatology IC would allow direct care to be provided alongside the oncology outpatient team. New immunologic therapies (cytotoxic T-lymphocyte–associated protein 4 and programmed cell death protein 1/programmed death-ligand 1 treatments) can cause dermatologic reactions in more than 40% of patients.¹⁷ Paraneoplastic syndromes can manifest with cutaneous symptoms, as can acute graft-vs-host-disease.¹⁸ In a study at Memorial Sloan Kettering (New York, New York) analyzing 426 same-day outpatient dermatology consultations, 17% of patients experienced interruptions in their cancer therapy, but 83% responded quickly to dermatologic treatment and resumed oncologic therapy—19% of them at a reduced dose.¹⁹ This is an important demonstration of prompt dermatologic consultation in an outpatient setting reducing interruptions to anticancer therapy. The heterogeneity of the cutaneous reactions seen from oncologic and immunomodulatory medications is profound, with more than 140 different types of skin-specific reactions.²⁰

Solid-organ transplant recipients also could benefit from urgent access to dermatology services. These patients are at a much higher risk for skin cancers, and a study showed that those who receive referrals to dermatology are seen sooner after transplantation (5.6 years) than those who self-refer (7.2 years). Importantly, annual skin cancer screenings are recommended to begin 1 year after transplantation.²¹

Direct access to dermatology care could benefit patients with complicated rheumatologic conditions who present with skin findings; for example, patients with lupus erythematosus or dermatomyositis can have a spectrum of disease ranging from skin-predominant to systemic manifestations. Identification and treatment of such diseases require collaboration between dermatologists and rheumatologists.²² Likewise, a study of a joint rheumatology-dermatology clinic for psoriatic arthritis showed that a multidisciplinary approach to management leads to decreased time for patients to obtain proper rheumatologic and dermatologic examination and a faster time to diagnosis; however, such multidisciplinary clinic models and approaches to care often are found only at large university-based hospitals.²³ In a patient population for whom time to diagnosis is crucial to avoid permanent changes such as joint destruction, a dermatology IC could fill this role in community hospitals and clinics. A dermatology IC also can serve patients with specific diagnoses who would benefit from more direct access to care; for example, in 2017 there were 131,430 ED visits for hidradenitis suppurativa (HS) in the United States. While HS is not uncommon, it usually is underdiagnosed because it can be challenging to differentiate from an uncomplicated abscess. Emergency department visits often are utilized for first-time presentations as well as flares of HS. In these situations, ED doctors can provide palliative treatment, but prompt referrals to dermatologists should be made for disease management to decrease recurrence.²⁴

Final Thoughts

A huge caveat to the dermatology urgent care system is determining what is deemed “urgent.” We propose starting with a referral-based system only from other physicians (including IC and urgent care) rather than having patients walk in directly. Ideally, as support and staff increases, the availability can increase as well. In our institution, we suggested half-day clinics staffed by varying physicians, with compensation models similar to an ED or IC physician rather than by productivity. Each group considering this kind of addition to patient care will need to assess these points in building an IC for dermatology. The University of Pennsylvania’s (Philadelphia, Pennsylvania) system of rapid-access clinics to facilitate access to care for patients requiring urgent appointments may function as a model for future similar clinics.²⁵ Creating a specialized IC/urgent care is not a novel concept. Orthopedic urgent care centers have increased greatly in the past decade, reducing ED burden for musculoskeletal complaints. In a study evaluating the utility of orthopedic urgent care settings, time to see an orthopedic specialist and cost were both greatly reduced with this system.¹ The same has been shown in same-day access ophthalmology clinics, which are organized similarly to an urgent care.²⁶

In 2021, there were 107.4 million treat-and-release visits to the ED in the United States for a total cost of $80.3 billion.²⁷ This emphasizes the need to consider care models that not only provide excellent clinical care and treat the most acute diagnoses promptly and accurately but also reduce overall costs. While this may be convoluted for other specialties given the difficulty of having patients self-triage, dermatologic concerns are similar to orthopedic concerns for the patient to decipher the etiology of the concern. As in orthopedics, a dermatology IC could function similarly, increasing access, decreasing ED and IC wait times, saving overall health care spending, and allowing underserved and publicly insured individuals to have improved, prompt care.

Emergency departments (EDs) and immediate care (IC) facilities often do not have prompt dermatologic care available for triage and treatment. Many EDs do not have staff dermatologists on call, instead relying on input from other specialists or quick outpatient dermatology appointments. It can be challenging to obtain a prompt appointment with a board-certified dermatologist, which is preferred for complex cases such as severe drug reactions or infection. In the United States, there are few well-established IC centers equipped to address dermatologic needs. The orthopedic specialty has modeled a concept that has led to the establishment of orthopedic urgent care/IC in many larger institutions,¹ and many private practice clinics serve their communities as well. We present a rationale for why a similar IC concept for dermatology would be beneficial, particularly within a large institution or health system.

Dermatology Consultation Changes Disease Management

There is diagnostic and therapeutic utility in dermatology evaluation. In a prospective study of 591 patients who were either hospitalized or evaluated in an ED/urgent care setting, treatment was changed in more than 60% of cases when dermatology consultation was utilized.² In another prospective review of 691 cases on an inpatient service, dermatology consultation resulted in treatment changes more than 80% of the time.³

Cellulitis has been a particularly well-studied diagnosis. Dermatologists often change the diagnosis of cellulitis in the hospital setting and reduce antibiotic exposure. In a prospective cohort study of 116 patients, 33.6% had their diagnosis of cellulitis changed to pseudocellulitis following evaluation by the dermatologist; of 34 patients who had started antibiotic therapy, 82.4% were recommended to discontinue the treatment, and all 39 patients with pseudocellulitis had a proven stable clinical course at 1-month follow-up.⁴ In another trial, 175 patients with presumed cellulitis were given standard management (provided by the medicine inpatient team) either alone or with the addition of dermatology consultation. Duration of antibiotic treatment (including intravenous therapy) was reduced when dermatology was consulted. Two weeks after discharge, patients who had dermatology consultations demonstrated greater clinical improvement.⁵

Improving ED and IC Access to Dermatology

Emergency department and IC teams across the United States work tirelessly to meet the demands of patients presenting with medically urgent conditions. In a study examining 861 ED cases, dermatology made up only 9.5% of specialist consultations, and in the opinion of the on-call dermatology resident, 51.0% (439/861) of cases warranted ED-level care.⁶

Data from the 2021 National Hospital Ambulatory Medical Care Survey showed that the mean wait time to see a physician, nurse, or physician assistant in an ED was 37.5 minutes, but wait times could range from less than 15 minutes to more than 6 hours.⁷ According to a study of 35,849 ED visits at nonfederal hospitals in the United States, only 47.7% of EDs admitted more than 90% of their patients within 6 hours.⁸ Moreover, perceived wait times in the ED have been shown to greatly impact patient satisfaction. Two predictors of perceived wait time include appropriate assessment of emergency level and the feeling of being forgotten.⁹ In a study of 2377 ED visits with primary dermatologic diagnoses, only 5.5% led to admission.¹⁰ This suggests many patients who come to the ED for dermatologic needs do not require inpatient hospital care. In these cases, patients with primary dermatologic concerns may experience longer ED wait times, as higher acuity or emergency cases take precedence. Studies also have shown that more vulnerable populations are utilizing ED visits most for primary dermatologic concerns.^10,11 This includes individuals of lower income and/or those with Medicaid/Medicare or those without insurance.¹¹ Predictors of high ED use for dermatologic concerns include prior frequent use of the ED (for nondermatologic concerns) instead of outpatient care, income below the poverty level, and lack of insurance; older individuals (>65 years) also were found to use the ED more frequently for dermatologic concerns when compared to younger individuals.¹⁰

Importantly, there is a great need for urgent dermatology consultation for pediatric patients. A single-institution study showed that over a 36-month period, there were 347 pediatric dermatology consultations from the pediatric ED mostly for children aged 0 days to 5 years; nearly half of these consultations required outpatient clinic follow-up.¹² However, dermatology outpatient follow-up can be difficult to obtain, especially for vulnerable groups. In a study of 611 dermatology clinics, patients with Medicaid were shown to have longer wait times and less success in obtaining dermatology appointments compared to those with Medicare or private insurance.¹³ Only about 30% of private dermatology practices accept Medicaid patients, likely pushing these patients toward utilization of emergency services for dermatologic concerns.^13,14

There is a clear role for a dermatology IC in our health care system, and the concept already has been identified and trialed in several institutions. At Oregon Health and Science University (Portland, Oregon), a retrospective chart review of patients with diagnoses of Morgellons disease and neurotic excoriations seen in dermatology urgent care between 2018 and 2020 showed an 88% decrease in annual rates of health care visits and a 77% decrease in ED visits after dermatology services were engaged compared to before the opening of the dermatology urgent care.¹⁵ Another study showed that uninsured or self-pay patients were more than 14 times more likely to access dermatology urgent care than to schedule a routine clinic appointment, suggesting that there is a barrier to making outpatient dermatologic appointments for uninsured patients. An urgent access model may facilitate the ability of underinsured patients to access care.¹⁶

Improving Dermatology Access for Other Specialties

Needs for dermatologic care are encountered in many other specialties. Having direct access to immediate dermatologic treatment is best for patients and may avoid inpatient care and trips to the ED for consultation access. Ideally, a dermatology IC would allow direct care to be provided alongside the oncology outpatient team. New immunologic therapies (cytotoxic T-lymphocyte–associated protein 4 and programmed cell death protein 1/programmed death-ligand 1 treatments) can cause dermatologic reactions in more than 40% of patients.¹⁷ Paraneoplastic syndromes can manifest with cutaneous symptoms, as can acute graft-vs-host-disease.¹⁸ In a study at Memorial Sloan Kettering (New York, New York) analyzing 426 same-day outpatient dermatology consultations, 17% of patients experienced interruptions in their cancer therapy, but 83% responded quickly to dermatologic treatment and resumed oncologic therapy—19% of them at a reduced dose.¹⁹ This is an important demonstration of prompt dermatologic consultation in an outpatient setting reducing interruptions to anticancer therapy. The heterogeneity of the cutaneous reactions seen from oncologic and immunomodulatory medications is profound, with more than 140 different types of skin-specific reactions.²⁰

Solid-organ transplant recipients also could benefit from urgent access to dermatology services. These patients are at a much higher risk for skin cancers, and a study showed that those who receive referrals to dermatology are seen sooner after transplantation (5.6 years) than those who self-refer (7.2 years). Importantly, annual skin cancer screenings are recommended to begin 1 year after transplantation.²¹

Direct access to dermatology care could benefit patients with complicated rheumatologic conditions who present with skin findings; for example, patients with lupus erythematosus or dermatomyositis can have a spectrum of disease ranging from skin-predominant to systemic manifestations. Identification and treatment of such diseases require collaboration between dermatologists and rheumatologists.²² Likewise, a study of a joint rheumatology-dermatology clinic for psoriatic arthritis showed that a multidisciplinary approach to management leads to decreased time for patients to obtain proper rheumatologic and dermatologic examination and a faster time to diagnosis; however, such multidisciplinary clinic models and approaches to care often are found only at large university-based hospitals.²³ In a patient population for whom time to diagnosis is crucial to avoid permanent changes such as joint destruction, a dermatology IC could fill this role in community hospitals and clinics. A dermatology IC also can serve patients with specific diagnoses who would benefit from more direct access to care; for example, in 2017 there were 131,430 ED visits for hidradenitis suppurativa (HS) in the United States. While HS is not uncommon, it usually is underdiagnosed because it can be challenging to differentiate from an uncomplicated abscess. Emergency department visits often are utilized for first-time presentations as well as flares of HS. In these situations, ED doctors can provide palliative treatment, but prompt referrals to dermatologists should be made for disease management to decrease recurrence.²⁴

Final Thoughts

A huge caveat to the dermatology urgent care system is determining what is deemed “urgent.” We propose starting with a referral-based system only from other physicians (including IC and urgent care) rather than having patients walk in directly. Ideally, as support and staff increases, the availability can increase as well. In our institution, we suggested half-day clinics staffed by varying physicians, with compensation models similar to an ED or IC physician rather than by productivity. Each group considering this kind of addition to patient care will need to assess these points in building an IC for dermatology. The University of Pennsylvania’s (Philadelphia, Pennsylvania) system of rapid-access clinics to facilitate access to care for patients requiring urgent appointments may function as a model for future similar clinics.²⁵ Creating a specialized IC/urgent care is not a novel concept. Orthopedic urgent care centers have increased greatly in the past decade, reducing ED burden for musculoskeletal complaints. In a study evaluating the utility of orthopedic urgent care settings, time to see an orthopedic specialist and cost were both greatly reduced with this system.¹ The same has been shown in same-day access ophthalmology clinics, which are organized similarly to an urgent care.²⁶

In 2021, there were 107.4 million treat-and-release visits to the ED in the United States for a total cost of $80.3 billion.²⁷ This emphasizes the need to consider care models that not only provide excellent clinical care and treat the most acute diagnoses promptly and accurately but also reduce overall costs. While this may be convoluted for other specialties given the difficulty of having patients self-triage, dermatologic concerns are similar to orthopedic concerns for the patient to decipher the etiology of the concern. As in orthopedics, a dermatology IC could function similarly, increasing access, decreasing ED and IC wait times, saving overall health care spending, and allowing underserved and publicly insured individuals to have improved, prompt care.

Emergency departments (EDs) and immediate care (IC) facilities often do not have prompt dermatologic care available for triage and treatment. Many EDs do not have staff dermatologists on call, instead relying on input from other specialists or quick outpatient dermatology appointments. It can be challenging to obtain a prompt appointment with a board-certified dermatologist, which is preferred for complex cases such as severe drug reactions or infection. In the United States, there are few well-established IC centers equipped to address dermatologic needs. The orthopedic specialty has modeled a concept that has led to the establishment of orthopedic urgent care/IC in many larger institutions,¹ and many private practice clinics serve their communities as well. We present a rationale for why a similar IC concept for dermatology would be beneficial, particularly within a large institution or health system.

Dermatology Consultation Changes Disease Management

There is diagnostic and therapeutic utility in dermatology evaluation. In a prospective study of 591 patients who were either hospitalized or evaluated in an ED/urgent care setting, treatment was changed in more than 60% of cases when dermatology consultation was utilized.² In another prospective review of 691 cases on an inpatient service, dermatology consultation resulted in treatment changes more than 80% of the time.³

Cellulitis has been a particularly well-studied diagnosis. Dermatologists often change the diagnosis of cellulitis in the hospital setting and reduce antibiotic exposure. In a prospective cohort study of 116 patients, 33.6% had their diagnosis of cellulitis changed to pseudocellulitis following evaluation by the dermatologist; of 34 patients who had started antibiotic therapy, 82.4% were recommended to discontinue the treatment, and all 39 patients with pseudocellulitis had a proven stable clinical course at 1-month follow-up.⁴ In another trial, 175 patients with presumed cellulitis were given standard management (provided by the medicine inpatient team) either alone or with the addition of dermatology consultation. Duration of antibiotic treatment (including intravenous therapy) was reduced when dermatology was consulted. Two weeks after discharge, patients who had dermatology consultations demonstrated greater clinical improvement.⁵

Improving ED and IC Access to Dermatology

Emergency department and IC teams across the United States work tirelessly to meet the demands of patients presenting with medically urgent conditions. In a study examining 861 ED cases, dermatology made up only 9.5% of specialist consultations, and in the opinion of the on-call dermatology resident, 51.0% (439/861) of cases warranted ED-level care.⁶

Data from the 2021 National Hospital Ambulatory Medical Care Survey showed that the mean wait time to see a physician, nurse, or physician assistant in an ED was 37.5 minutes, but wait times could range from less than 15 minutes to more than 6 hours.⁷ According to a study of 35,849 ED visits at nonfederal hospitals in the United States, only 47.7% of EDs admitted more than 90% of their patients within 6 hours.⁸ Moreover, perceived wait times in the ED have been shown to greatly impact patient satisfaction. Two predictors of perceived wait time include appropriate assessment of emergency level and the feeling of being forgotten.⁹ In a study of 2377 ED visits with primary dermatologic diagnoses, only 5.5% led to admission.¹⁰ This suggests many patients who come to the ED for dermatologic needs do not require inpatient hospital care. In these cases, patients with primary dermatologic concerns may experience longer ED wait times, as higher acuity or emergency cases take precedence. Studies also have shown that more vulnerable populations are utilizing ED visits most for primary dermatologic concerns.^10,11 This includes individuals of lower income and/or those with Medicaid/Medicare or those without insurance.¹¹ Predictors of high ED use for dermatologic concerns include prior frequent use of the ED (for nondermatologic concerns) instead of outpatient care, income below the poverty level, and lack of insurance; older individuals (>65 years) also were found to use the ED more frequently for dermatologic concerns when compared to younger individuals.¹⁰

Importantly, there is a great need for urgent dermatology consultation for pediatric patients. A single-institution study showed that over a 36-month period, there were 347 pediatric dermatology consultations from the pediatric ED mostly for children aged 0 days to 5 years; nearly half of these consultations required outpatient clinic follow-up.¹² However, dermatology outpatient follow-up can be difficult to obtain, especially for vulnerable groups. In a study of 611 dermatology clinics, patients with Medicaid were shown to have longer wait times and less success in obtaining dermatology appointments compared to those with Medicare or private insurance.¹³ Only about 30% of private dermatology practices accept Medicaid patients, likely pushing these patients toward utilization of emergency services for dermatologic concerns.^13,14

There is a clear role for a dermatology IC in our health care system, and the concept already has been identified and trialed in several institutions. At Oregon Health and Science University (Portland, Oregon), a retrospective chart review of patients with diagnoses of Morgellons disease and neurotic excoriations seen in dermatology urgent care between 2018 and 2020 showed an 88% decrease in annual rates of health care visits and a 77% decrease in ED visits after dermatology services were engaged compared to before the opening of the dermatology urgent care.¹⁵ Another study showed that uninsured or self-pay patients were more than 14 times more likely to access dermatology urgent care than to schedule a routine clinic appointment, suggesting that there is a barrier to making outpatient dermatologic appointments for uninsured patients. An urgent access model may facilitate the ability of underinsured patients to access care.¹⁶

Improving Dermatology Access for Other Specialties

Needs for dermatologic care are encountered in many other specialties. Having direct access to immediate dermatologic treatment is best for patients and may avoid inpatient care and trips to the ED for consultation access. Ideally, a dermatology IC would allow direct care to be provided alongside the oncology outpatient team. New immunologic therapies (cytotoxic T-lymphocyte–associated protein 4 and programmed cell death protein 1/programmed death-ligand 1 treatments) can cause dermatologic reactions in more than 40% of patients.¹⁷ Paraneoplastic syndromes can manifest with cutaneous symptoms, as can acute graft-vs-host-disease.¹⁸ In a study at Memorial Sloan Kettering (New York, New York) analyzing 426 same-day outpatient dermatology consultations, 17% of patients experienced interruptions in their cancer therapy, but 83% responded quickly to dermatologic treatment and resumed oncologic therapy—19% of them at a reduced dose.¹⁹ This is an important demonstration of prompt dermatologic consultation in an outpatient setting reducing interruptions to anticancer therapy. The heterogeneity of the cutaneous reactions seen from oncologic and immunomodulatory medications is profound, with more than 140 different types of skin-specific reactions.²⁰

Solid-organ transplant recipients also could benefit from urgent access to dermatology services. These patients are at a much higher risk for skin cancers, and a study showed that those who receive referrals to dermatology are seen sooner after transplantation (5.6 years) than those who self-refer (7.2 years). Importantly, annual skin cancer screenings are recommended to begin 1 year after transplantation.²¹

Direct access to dermatology care could benefit patients with complicated rheumatologic conditions who present with skin findings; for example, patients with lupus erythematosus or dermatomyositis can have a spectrum of disease ranging from skin-predominant to systemic manifestations. Identification and treatment of such diseases require collaboration between dermatologists and rheumatologists.²² Likewise, a study of a joint rheumatology-dermatology clinic for psoriatic arthritis showed that a multidisciplinary approach to management leads to decreased time for patients to obtain proper rheumatologic and dermatologic examination and a faster time to diagnosis; however, such multidisciplinary clinic models and approaches to care often are found only at large university-based hospitals.²³ In a patient population for whom time to diagnosis is crucial to avoid permanent changes such as joint destruction, a dermatology IC could fill this role in community hospitals and clinics. A dermatology IC also can serve patients with specific diagnoses who would benefit from more direct access to care; for example, in 2017 there were 131,430 ED visits for hidradenitis suppurativa (HS) in the United States. While HS is not uncommon, it usually is underdiagnosed because it can be challenging to differentiate from an uncomplicated abscess. Emergency department visits often are utilized for first-time presentations as well as flares of HS. In these situations, ED doctors can provide palliative treatment, but prompt referrals to dermatologists should be made for disease management to decrease recurrence.²⁴

Final Thoughts

A huge caveat to the dermatology urgent care system is determining what is deemed “urgent.” We propose starting with a referral-based system only from other physicians (including IC and urgent care) rather than having patients walk in directly. Ideally, as support and staff increases, the availability can increase as well. In our institution, we suggested half-day clinics staffed by varying physicians, with compensation models similar to an ED or IC physician rather than by productivity. Each group considering this kind of addition to patient care will need to assess these points in building an IC for dermatology. The University of Pennsylvania’s (Philadelphia, Pennsylvania) system of rapid-access clinics to facilitate access to care for patients requiring urgent appointments may function as a model for future similar clinics.²⁵ Creating a specialized IC/urgent care is not a novel concept. Orthopedic urgent care centers have increased greatly in the past decade, reducing ED burden for musculoskeletal complaints. In a study evaluating the utility of orthopedic urgent care settings, time to see an orthopedic specialist and cost were both greatly reduced with this system.¹ The same has been shown in same-day access ophthalmology clinics, which are organized similarly to an urgent care.²⁶

In 2021, there were 107.4 million treat-and-release visits to the ED in the United States for a total cost of $80.3 billion.²⁷ This emphasizes the need to consider care models that not only provide excellent clinical care and treat the most acute diagnoses promptly and accurately but also reduce overall costs. While this may be convoluted for other specialties given the difficulty of having patients self-triage, dermatologic concerns are similar to orthopedic concerns for the patient to decipher the etiology of the concern. As in orthopedics, a dermatology IC could function similarly, increasing access, decreasing ED and IC wait times, saving overall health care spending, and allowing underserved and publicly insured individuals to have improved, prompt care.

THE DIAGNOSIS: Villar Nodule

The biopsy revealed features consistent with cutaneous endometriosis in the setting of a painful, tender, multilobulated nodule with a cyclical bleeding pattern (Figure 1). The bleeding pattern of the nodule during menses and lack of surgical history supported the diagnosis of primary cutaneous endometriosis in our patient. She was diagnosed with endometriosis by gynecology, and her primary care physician started her on an oral contraceptive based on this diagnosis. She also was referred to gynecology and plastic surgery for a joint surgical consultation to remove the nodule. She initially decided to do a trial of the oral contraceptive but subsequently underwent umbilical endometrioma excision with neo-umbilicus creation with no evidence of recurrence.

Primary cutaneous endometriosis should be considered in young females who present with tender umbilical nodules. Endometriosis refers to the presence of an endometriumlike epithelium outside the endometrium and myometrium.¹ The condition affects 10% to 15% of reproductive-aged (ie, 18-49 years) women in the United States and typically involves tissues within the pelvis, such as the ovaries, pouch of Douglas, or pelvic ligaments.² Cutaneous endometriosis is the growth of endometrial tissue in the skin and is rare, accounting for less than 5.5% of cases of extrapelvic endometriosis worldwide, affecting primarily the umbilicus, abdominal wall, and vulva.^3,4

The 2 main types of cutaneous endometriosis are primary (spontaneous) and secondary. Primary lesions develop in patients without prior surgical history, and secondary lesions occur within previous surgical incision sites, often scars from cesarean delivery.⁵ Less than 30% of cases of cutaneous endometriosis are primary disease.⁶ Primary cutaneous endometriosis of the umbilicus, known as Villar nodule, was first described in 1886.^3,7 Up to 40% of patients with extrapelvic endometriosis worldwide presented with Villar nodules in a systematic literature review.⁶ The prevalence of these nodules is unknown, but the incidence is less than 1% of cases of extragenital endometriosis.⁴

There are 2 leading theories of primary cutaneous endometriosis pathogenesis. The first is the transportation theory, in which endometrial cells are transported outside the uterus via the lymphatic system.⁸ The second is the metaplasia theory, which proposed that endometrial cells develop in the coelomic mesothelium in the presence of high estrogen levels.^8,9

Secondary cutaneous endometriosis, also known as scar endometriosis, is suspected to be caused by an iatrogenic implantation of endometrial cells at the scar of a prior surgical site.⁹ Although our patient had an existing umbilicus scar from a piercing, it was improbable for that to have been the nidus, as the keloid scar was superficial and did not have contact with the abdominal cavity for iatrogenic implantation. Clinical diagnosis for secondary cutaneous endometriosis often is made based on a triad of features: a nonmalignant abdominal mass, recurring pain and bleeding of the lesion with menses, and prior history of abdominal surgery.^9,10 On clinical examination, these features typically manifest as a palpable subcutaneous mass that is black, blue, brown, or red. Often, the lesions enlarge and bleed during the menstrual cycle, causing pain, tenderness, or pruritus.³ Dermoscopic features of secondary cutaneous endometriosis are erythematous umbilical nodules with a homogeneous vascular pattern that appears red with a brownish hue (Figure 2).^9,11 Dermoscopic features may vary with the hormone cycle; for example, the follicular phase (correlating with day 7 of menses) demonstrates polypoid projections, erythematous violaceous color, dark-brown spots, and active bleeding of the lesion.¹² Clinical and dermoscopic examination are useful tools in this diagnosis.

Imaging such as ultrasonography, computed tomography, or magnetic resonance imaging may be useful in identifying abdominal endometriomas.^8,13,14 Pelvic involvement of endometriosis was found in approximately 15% of patients in a case series,⁴ with concurrent primary umbilical endometriosis. Imaging studies may assist evaluation for fistula formation, presence of malignancies, and the extent of endometriosis within the abdominal cavity.

Histopathology is key to confirming cutaneous endometriosis and shows multiple bland-appearing glands of varying sizes with loose, concentric, edematous, or fibromyxoid stroma (Figure 1).³ Red blood cells sometimes are found with hemosiderin within the stroma. Immunohistochemical staining with estrogen receptors may aid in identifying the endometriumlike epithelial cells.¹³

Standard treatment involves surgical excision with 1-cm margins and umbilical preservation, which results in a recurrence rate of less than 10%.^4,10 Medical therapy, such as aromatase inhibitors, progestogens, antiprogestogens, combined oral contraceptives, or gonadotropin-releasing hormone agonists or antagonists may help manage pain or reduce the size of the nodule.^4,15 Simple observation also is a potential course for patients who decline treatment options.

Differential diagnoses include lobular capillary hemangioma, also known as pyogenic granuloma; Sister Mary Joseph nodule; umbilical hernia; and dermatofibrosarcoma protuberans. Lobular capillary hemangiomas commonly are acquired benign vascular proliferations of the skin that are friable and tend to ulcerate.¹⁶ These lesions typically grow rapidly and often are located on the face, lips, mucosae, and fingers. Histopathologic examination may show an exophytic lesion with lobules of proliferating capillaries within an edematous matrix, superficial ulceration, and an epithelial collarette.¹⁷ Treatment includes surgical excision, cauterization, laser treatments, sclerotherapy, injectable medications, and topical medications, but recurrence is possible with any of these interventions.¹⁸

Cutaneous metastasis of an internal solid organ cancer, commonly known as a Sister Mary Joseph nodule, typically manifests as an erythematous, irregularly shaped nodule that may protrude from the umbilicus.¹⁴ Gastrointestinal symptoms such as change in bowel habits or obstructive symptoms in the setting of a progressive malignancy are common.¹⁴ Clinical features include a firm fixed lesion, oozing, and ulceration.¹⁹ On dermoscopy, polymorphous vascular patterns, milky red structureless areas, and white lines typically are present.¹¹ Although dermoscopic features may differentiate this entity from cutaneous endometriosis, tissue sampling and histologic examination are crucial diagnostic tools to identify malignant vs benign lesions.

An umbilical hernia is a protrusion of omentum, bowel, or other intra-abdominal organs in an abdominal wall defect. Clinical presentation includes a soft protrusion that may be reduced on palpation if nonstrangulated.²⁰ Treatment includes watchful waiting or surgical repair. The reducibility and presence of an abdominal wall defect may point to this diagnosis. Imaging also may aid in the diagnosis if the history and physical examination are unclear.

Dermatofibrosarcoma protuberans is a slow-developing, low- to intermediate-grade, soft-tissue sarcoma that occurs in less than 0.1% of all cancers in the United States.²¹ Lesions often manifest as small, firm, slow-growing, painless, flesh-colored dermal plaques; subcutaneous thickening; or atrophic nonprotuberant lesions typically involving the trunk.²¹ Histopathologically, they are composed of uniform spindle-cell proliferation growing in a storiform pattern and subcutaneous fat trapping that has strong and diffuse CD34 immunoreactivity.^21,22 Pathologic examination typically distinguishes this diagnosis from cutaneous endometriosis. Treatment includes tumor resection that may or may not involve radiotherapy and targeted therapy, as recurrence and metastases are possible.

Primary cutaneous endometriosis is a rare but important diagnosis for dermatologists to consider when evaluating umbilical nodules. Clinical features may include bleeding masses during menses in females of reproductive age. Dermoscopic examination aids in workup, and histopathologic testing can confirm the diagnosis and rule out malignancies. Surgical excision is the treatment of choice with a low rate of recurrence.

THE DIAGNOSIS: Villar Nodule

The biopsy revealed features consistent with cutaneous endometriosis in the setting of a painful, tender, multilobulated nodule with a cyclical bleeding pattern (Figure 1). The bleeding pattern of the nodule during menses and lack of surgical history supported the diagnosis of primary cutaneous endometriosis in our patient. She was diagnosed with endometriosis by gynecology, and her primary care physician started her on an oral contraceptive based on this diagnosis. She also was referred to gynecology and plastic surgery for a joint surgical consultation to remove the nodule. She initially decided to do a trial of the oral contraceptive but subsequently underwent umbilical endometrioma excision with neo-umbilicus creation with no evidence of recurrence.

Primary cutaneous endometriosis should be considered in young females who present with tender umbilical nodules. Endometriosis refers to the presence of an endometriumlike epithelium outside the endometrium and myometrium.¹ The condition affects 10% to 15% of reproductive-aged (ie, 18-49 years) women in the United States and typically involves tissues within the pelvis, such as the ovaries, pouch of Douglas, or pelvic ligaments.² Cutaneous endometriosis is the growth of endometrial tissue in the skin and is rare, accounting for less than 5.5% of cases of extrapelvic endometriosis worldwide, affecting primarily the umbilicus, abdominal wall, and vulva.^3,4

The 2 main types of cutaneous endometriosis are primary (spontaneous) and secondary. Primary lesions develop in patients without prior surgical history, and secondary lesions occur within previous surgical incision sites, often scars from cesarean delivery.⁵ Less than 30% of cases of cutaneous endometriosis are primary disease.⁶ Primary cutaneous endometriosis of the umbilicus, known as Villar nodule, was first described in 1886.^3,7 Up to 40% of patients with extrapelvic endometriosis worldwide presented with Villar nodules in a systematic literature review.⁶ The prevalence of these nodules is unknown, but the incidence is less than 1% of cases of extragenital endometriosis.⁴

There are 2 leading theories of primary cutaneous endometriosis pathogenesis. The first is the transportation theory, in which endometrial cells are transported outside the uterus via the lymphatic system.⁸ The second is the metaplasia theory, which proposed that endometrial cells develop in the coelomic mesothelium in the presence of high estrogen levels.^8,9

Secondary cutaneous endometriosis, also known as scar endometriosis, is suspected to be caused by an iatrogenic implantation of endometrial cells at the scar of a prior surgical site.⁹ Although our patient had an existing umbilicus scar from a piercing, it was improbable for that to have been the nidus, as the keloid scar was superficial and did not have contact with the abdominal cavity for iatrogenic implantation. Clinical diagnosis for secondary cutaneous endometriosis often is made based on a triad of features: a nonmalignant abdominal mass, recurring pain and bleeding of the lesion with menses, and prior history of abdominal surgery.^9,10 On clinical examination, these features typically manifest as a palpable subcutaneous mass that is black, blue, brown, or red. Often, the lesions enlarge and bleed during the menstrual cycle, causing pain, tenderness, or pruritus.³ Dermoscopic features of secondary cutaneous endometriosis are erythematous umbilical nodules with a homogeneous vascular pattern that appears red with a brownish hue (Figure 2).^9,11 Dermoscopic features may vary with the hormone cycle; for example, the follicular phase (correlating with day 7 of menses) demonstrates polypoid projections, erythematous violaceous color, dark-brown spots, and active bleeding of the lesion.¹² Clinical and dermoscopic examination are useful tools in this diagnosis.

Imaging such as ultrasonography, computed tomography, or magnetic resonance imaging may be useful in identifying abdominal endometriomas.^8,13,14 Pelvic involvement of endometriosis was found in approximately 15% of patients in a case series,⁴ with concurrent primary umbilical endometriosis. Imaging studies may assist evaluation for fistula formation, presence of malignancies, and the extent of endometriosis within the abdominal cavity.

Histopathology is key to confirming cutaneous endometriosis and shows multiple bland-appearing glands of varying sizes with loose, concentric, edematous, or fibromyxoid stroma (Figure 1).³ Red blood cells sometimes are found with hemosiderin within the stroma. Immunohistochemical staining with estrogen receptors may aid in identifying the endometriumlike epithelial cells.¹³

Standard treatment involves surgical excision with 1-cm margins and umbilical preservation, which results in a recurrence rate of less than 10%.^4,10 Medical therapy, such as aromatase inhibitors, progestogens, antiprogestogens, combined oral contraceptives, or gonadotropin-releasing hormone agonists or antagonists may help manage pain or reduce the size of the nodule.^4,15 Simple observation also is a potential course for patients who decline treatment options.

Differential diagnoses include lobular capillary hemangioma, also known as pyogenic granuloma; Sister Mary Joseph nodule; umbilical hernia; and dermatofibrosarcoma protuberans. Lobular capillary hemangiomas commonly are acquired benign vascular proliferations of the skin that are friable and tend to ulcerate.¹⁶ These lesions typically grow rapidly and often are located on the face, lips, mucosae, and fingers. Histopathologic examination may show an exophytic lesion with lobules of proliferating capillaries within an edematous matrix, superficial ulceration, and an epithelial collarette.¹⁷ Treatment includes surgical excision, cauterization, laser treatments, sclerotherapy, injectable medications, and topical medications, but recurrence is possible with any of these interventions.¹⁸

Cutaneous metastasis of an internal solid organ cancer, commonly known as a Sister Mary Joseph nodule, typically manifests as an erythematous, irregularly shaped nodule that may protrude from the umbilicus.¹⁴ Gastrointestinal symptoms such as change in bowel habits or obstructive symptoms in the setting of a progressive malignancy are common.¹⁴ Clinical features include a firm fixed lesion, oozing, and ulceration.¹⁹ On dermoscopy, polymorphous vascular patterns, milky red structureless areas, and white lines typically are present.¹¹ Although dermoscopic features may differentiate this entity from cutaneous endometriosis, tissue sampling and histologic examination are crucial diagnostic tools to identify malignant vs benign lesions.

An umbilical hernia is a protrusion of omentum, bowel, or other intra-abdominal organs in an abdominal wall defect. Clinical presentation includes a soft protrusion that may be reduced on palpation if nonstrangulated.²⁰ Treatment includes watchful waiting or surgical repair. The reducibility and presence of an abdominal wall defect may point to this diagnosis. Imaging also may aid in the diagnosis if the history and physical examination are unclear.

Dermatofibrosarcoma protuberans is a slow-developing, low- to intermediate-grade, soft-tissue sarcoma that occurs in less than 0.1% of all cancers in the United States.²¹ Lesions often manifest as small, firm, slow-growing, painless, flesh-colored dermal plaques; subcutaneous thickening; or atrophic nonprotuberant lesions typically involving the trunk.²¹ Histopathologically, they are composed of uniform spindle-cell proliferation growing in a storiform pattern and subcutaneous fat trapping that has strong and diffuse CD34 immunoreactivity.^21,22 Pathologic examination typically distinguishes this diagnosis from cutaneous endometriosis. Treatment includes tumor resection that may or may not involve radiotherapy and targeted therapy, as recurrence and metastases are possible.

Primary cutaneous endometriosis is a rare but important diagnosis for dermatologists to consider when evaluating umbilical nodules. Clinical features may include bleeding masses during menses in females of reproductive age. Dermoscopic examination aids in workup, and histopathologic testing can confirm the diagnosis and rule out malignancies. Surgical excision is the treatment of choice with a low rate of recurrence.

THE DIAGNOSIS: Villar Nodule

The biopsy revealed features consistent with cutaneous endometriosis in the setting of a painful, tender, multilobulated nodule with a cyclical bleeding pattern (Figure 1). The bleeding pattern of the nodule during menses and lack of surgical history supported the diagnosis of primary cutaneous endometriosis in our patient. She was diagnosed with endometriosis by gynecology, and her primary care physician started her on an oral contraceptive based on this diagnosis. She also was referred to gynecology and plastic surgery for a joint surgical consultation to remove the nodule. She initially decided to do a trial of the oral contraceptive but subsequently underwent umbilical endometrioma excision with neo-umbilicus creation with no evidence of recurrence.

Primary cutaneous endometriosis should be considered in young females who present with tender umbilical nodules. Endometriosis refers to the presence of an endometriumlike epithelium outside the endometrium and myometrium.¹ The condition affects 10% to 15% of reproductive-aged (ie, 18-49 years) women in the United States and typically involves tissues within the pelvis, such as the ovaries, pouch of Douglas, or pelvic ligaments.² Cutaneous endometriosis is the growth of endometrial tissue in the skin and is rare, accounting for less than 5.5% of cases of extrapelvic endometriosis worldwide, affecting primarily the umbilicus, abdominal wall, and vulva.^3,4

The 2 main types of cutaneous endometriosis are primary (spontaneous) and secondary. Primary lesions develop in patients without prior surgical history, and secondary lesions occur within previous surgical incision sites, often scars from cesarean delivery.⁵ Less than 30% of cases of cutaneous endometriosis are primary disease.⁶ Primary cutaneous endometriosis of the umbilicus, known as Villar nodule, was first described in 1886.^3,7 Up to 40% of patients with extrapelvic endometriosis worldwide presented with Villar nodules in a systematic literature review.⁶ The prevalence of these nodules is unknown, but the incidence is less than 1% of cases of extragenital endometriosis.⁴

There are 2 leading theories of primary cutaneous endometriosis pathogenesis. The first is the transportation theory, in which endometrial cells are transported outside the uterus via the lymphatic system.⁸ The second is the metaplasia theory, which proposed that endometrial cells develop in the coelomic mesothelium in the presence of high estrogen levels.^8,9

Secondary cutaneous endometriosis, also known as scar endometriosis, is suspected to be caused by an iatrogenic implantation of endometrial cells at the scar of a prior surgical site.⁹ Although our patient had an existing umbilicus scar from a piercing, it was improbable for that to have been the nidus, as the keloid scar was superficial and did not have contact with the abdominal cavity for iatrogenic implantation. Clinical diagnosis for secondary cutaneous endometriosis often is made based on a triad of features: a nonmalignant abdominal mass, recurring pain and bleeding of the lesion with menses, and prior history of abdominal surgery.^9,10 On clinical examination, these features typically manifest as a palpable subcutaneous mass that is black, blue, brown, or red. Often, the lesions enlarge and bleed during the menstrual cycle, causing pain, tenderness, or pruritus.³ Dermoscopic features of secondary cutaneous endometriosis are erythematous umbilical nodules with a homogeneous vascular pattern that appears red with a brownish hue (Figure 2).^9,11 Dermoscopic features may vary with the hormone cycle; for example, the follicular phase (correlating with day 7 of menses) demonstrates polypoid projections, erythematous violaceous color, dark-brown spots, and active bleeding of the lesion.¹² Clinical and dermoscopic examination are useful tools in this diagnosis.

Imaging such as ultrasonography, computed tomography, or magnetic resonance imaging may be useful in identifying abdominal endometriomas.^8,13,14 Pelvic involvement of endometriosis was found in approximately 15% of patients in a case series,⁴ with concurrent primary umbilical endometriosis. Imaging studies may assist evaluation for fistula formation, presence of malignancies, and the extent of endometriosis within the abdominal cavity.

Histopathology is key to confirming cutaneous endometriosis and shows multiple bland-appearing glands of varying sizes with loose, concentric, edematous, or fibromyxoid stroma (Figure 1).³ Red blood cells sometimes are found with hemosiderin within the stroma. Immunohistochemical staining with estrogen receptors may aid in identifying the endometriumlike epithelial cells.¹³

Standard treatment involves surgical excision with 1-cm margins and umbilical preservation, which results in a recurrence rate of less than 10%.^4,10 Medical therapy, such as aromatase inhibitors, progestogens, antiprogestogens, combined oral contraceptives, or gonadotropin-releasing hormone agonists or antagonists may help manage pain or reduce the size of the nodule.^4,15 Simple observation also is a potential course for patients who decline treatment options.

Differential diagnoses include lobular capillary hemangioma, also known as pyogenic granuloma; Sister Mary Joseph nodule; umbilical hernia; and dermatofibrosarcoma protuberans. Lobular capillary hemangiomas commonly are acquired benign vascular proliferations of the skin that are friable and tend to ulcerate.¹⁶ These lesions typically grow rapidly and often are located on the face, lips, mucosae, and fingers. Histopathologic examination may show an exophytic lesion with lobules of proliferating capillaries within an edematous matrix, superficial ulceration, and an epithelial collarette.¹⁷ Treatment includes surgical excision, cauterization, laser treatments, sclerotherapy, injectable medications, and topical medications, but recurrence is possible with any of these interventions.¹⁸

Cutaneous metastasis of an internal solid organ cancer, commonly known as a Sister Mary Joseph nodule, typically manifests as an erythematous, irregularly shaped nodule that may protrude from the umbilicus.¹⁴ Gastrointestinal symptoms such as change in bowel habits or obstructive symptoms in the setting of a progressive malignancy are common.¹⁴ Clinical features include a firm fixed lesion, oozing, and ulceration.¹⁹ On dermoscopy, polymorphous vascular patterns, milky red structureless areas, and white lines typically are present.¹¹ Although dermoscopic features may differentiate this entity from cutaneous endometriosis, tissue sampling and histologic examination are crucial diagnostic tools to identify malignant vs benign lesions.

An umbilical hernia is a protrusion of omentum, bowel, or other intra-abdominal organs in an abdominal wall defect. Clinical presentation includes a soft protrusion that may be reduced on palpation if nonstrangulated.²⁰ Treatment includes watchful waiting or surgical repair. The reducibility and presence of an abdominal wall defect may point to this diagnosis. Imaging also may aid in the diagnosis if the history and physical examination are unclear.

Dermatofibrosarcoma protuberans is a slow-developing, low- to intermediate-grade, soft-tissue sarcoma that occurs in less than 0.1% of all cancers in the United States.²¹ Lesions often manifest as small, firm, slow-growing, painless, flesh-colored dermal plaques; subcutaneous thickening; or atrophic nonprotuberant lesions typically involving the trunk.²¹ Histopathologically, they are composed of uniform spindle-cell proliferation growing in a storiform pattern and subcutaneous fat trapping that has strong and diffuse CD34 immunoreactivity.^21,22 Pathologic examination typically distinguishes this diagnosis from cutaneous endometriosis. Treatment includes tumor resection that may or may not involve radiotherapy and targeted therapy, as recurrence and metastases are possible.

Primary cutaneous endometriosis is a rare but important diagnosis for dermatologists to consider when evaluating umbilical nodules. Clinical features may include bleeding masses during menses in females of reproductive age. Dermoscopic examination aids in workup, and histopathologic testing can confirm the diagnosis and rule out malignancies. Surgical excision is the treatment of choice with a low rate of recurrence.