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Dermoscopic Documentation of a No-see-um Bite
Dermoscopic Documentation of a No-see-um Bite
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
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.
- Hill CA, MacDonald JF. Biting midges: biology and public health risk. Purdue University. Published July 2013. Accessed September 3, 2025. http://extension.entm.purdue.edu/publichealth/insects/bitingmidge.html
- Borkent A, Dominiak P. Catalog of the biting midges of the world (Diptera: Ceratopogonidae). Zootaxa. 2020;4787:1-377.
- Connelly CR. Biting midges, no-see-ums Culicoides spp. (Insecta: Diptera: Ceratopogonidae). University of Florida publication #EENY 349. Published August 2, 2022. Accessed September 3, 2025. https://edis.ifas.ufl.edu/publication/IN626
- Mullen GR, Murphree CS. Biting midges (Ceratopogonidae). In: Mullen GR, Durden LA, eds. Medical and Veterinary Entomology. 3rd ed. Academic Press; 2019:213-236.
- Best Bee Brothers. No-see-um seasonality range map & season information. Published March 4, 2022. Accessed September 3, 2025. https://bestbeebrothers.com/blogs/blog/no-see-um-season
- Biology Insights. Is there a season for no see ums in Florida? Published August 28, 2025. Accessed September 16, 2025. https://biologyinsights.com/is-there-a-season-for-no-see-ums-in-florida/
- Burris S. Florida no see ums: how to navigate the woes of no see ums in Florida. The Bug Agenda. Published February 2, 2022. Accessed September 3, 2025. https://thebugagenda.com/no-see-ums-in-florida/
- Steffen C. Clinical and histopathologic correlation of midge bites. Arch Dermatol. 1981;117:785-787.
- Krakowski AC, Ho B. Arthropod assault from biting midges. J Pediatr. 2013;163:298.
- Maves RC, Reaves EJ, Martin GJ. Images in clinical tropical medicine: bullous leg lesions caused by Culicoides midges after travel in the Amazon basin. Am J Trop Med Hyg. 2010;83:447.
- Swank B. How long do no-see-ums live? Pest Source. Updated March 17, 2025. Accessed September 3, 2025. https://pestsource.com/no-see-um/lifespan/
- Nguyen QD, Vu MN, Herbert AA. Insect repellents: an updated review for the clinician. J Am Acad Dermatol. 2023;88:123-130.
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
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
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.
- Hill CA, MacDonald JF. Biting midges: biology and public health risk. Purdue University. Published July 2013. Accessed September 3, 2025. http://extension.entm.purdue.edu/publichealth/insects/bitingmidge.html
- Borkent A, Dominiak P. Catalog of the biting midges of the world (Diptera: Ceratopogonidae). Zootaxa. 2020;4787:1-377.
- Connelly CR. Biting midges, no-see-ums Culicoides spp. (Insecta: Diptera: Ceratopogonidae). University of Florida publication #EENY 349. Published August 2, 2022. Accessed September 3, 2025. https://edis.ifas.ufl.edu/publication/IN626
- Mullen GR, Murphree CS. Biting midges (Ceratopogonidae). In: Mullen GR, Durden LA, eds. Medical and Veterinary Entomology. 3rd ed. Academic Press; 2019:213-236.
- Best Bee Brothers. No-see-um seasonality range map & season information. Published March 4, 2022. Accessed September 3, 2025. https://bestbeebrothers.com/blogs/blog/no-see-um-season
- Biology Insights. Is there a season for no see ums in Florida? Published August 28, 2025. Accessed September 16, 2025. https://biologyinsights.com/is-there-a-season-for-no-see-ums-in-florida/
- Burris S. Florida no see ums: how to navigate the woes of no see ums in Florida. The Bug Agenda. Published February 2, 2022. Accessed September 3, 2025. https://thebugagenda.com/no-see-ums-in-florida/
- Steffen C. Clinical and histopathologic correlation of midge bites. Arch Dermatol. 1981;117:785-787.
- Krakowski AC, Ho B. Arthropod assault from biting midges. J Pediatr. 2013;163:298.
- Maves RC, Reaves EJ, Martin GJ. Images in clinical tropical medicine: bullous leg lesions caused by Culicoides midges after travel in the Amazon basin. Am J Trop Med Hyg. 2010;83:447.
- Swank B. How long do no-see-ums live? Pest Source. Updated March 17, 2025. Accessed September 3, 2025. https://pestsource.com/no-see-um/lifespan/
- Nguyen QD, Vu MN, Herbert AA. Insect repellents: an updated review for the clinician. J Am Acad Dermatol. 2023;88:123-130.
- Hill CA, MacDonald JF. Biting midges: biology and public health risk. Purdue University. Published July 2013. Accessed September 3, 2025. http://extension.entm.purdue.edu/publichealth/insects/bitingmidge.html
- Borkent A, Dominiak P. Catalog of the biting midges of the world (Diptera: Ceratopogonidae). Zootaxa. 2020;4787:1-377.
- Connelly CR. Biting midges, no-see-ums Culicoides spp. (Insecta: Diptera: Ceratopogonidae). University of Florida publication #EENY 349. Published August 2, 2022. Accessed September 3, 2025. https://edis.ifas.ufl.edu/publication/IN626
- Mullen GR, Murphree CS. Biting midges (Ceratopogonidae). In: Mullen GR, Durden LA, eds. Medical and Veterinary Entomology. 3rd ed. Academic Press; 2019:213-236.
- Best Bee Brothers. No-see-um seasonality range map & season information. Published March 4, 2022. Accessed September 3, 2025. https://bestbeebrothers.com/blogs/blog/no-see-um-season
- Biology Insights. Is there a season for no see ums in Florida? Published August 28, 2025. Accessed September 16, 2025. https://biologyinsights.com/is-there-a-season-for-no-see-ums-in-florida/
- Burris S. Florida no see ums: how to navigate the woes of no see ums in Florida. The Bug Agenda. Published February 2, 2022. Accessed September 3, 2025. https://thebugagenda.com/no-see-ums-in-florida/
- Steffen C. Clinical and histopathologic correlation of midge bites. Arch Dermatol. 1981;117:785-787.
- Krakowski AC, Ho B. Arthropod assault from biting midges. J Pediatr. 2013;163:298.
- Maves RC, Reaves EJ, Martin GJ. Images in clinical tropical medicine: bullous leg lesions caused by Culicoides midges after travel in the Amazon basin. Am J Trop Med Hyg. 2010;83:447.
- Swank B. How long do no-see-ums live? Pest Source. Updated March 17, 2025. Accessed September 3, 2025. https://pestsource.com/no-see-um/lifespan/
- Nguyen QD, Vu MN, Herbert AA. Insect repellents: an updated review for the clinician. J Am Acad Dermatol. 2023;88:123-130.
Dermoscopic Documentation of a No-see-um Bite
Dermoscopic Documentation of a No-see-um Bite
Practice Points
- Biting midges, commonly known as no-see-ums, are extremely small flies whose bites can cause a burning sensation, mild pain, and reactions ranging from small wheals to intensely pruritic papules.
- Medical management of no-see-um bites is based on the severity of the skin reaction.
