Cutaneous onchocercoma

Onchocerciasis is a common, chronic multisystem disease with dermatologic, ocular, and systemic manifestations. Although the disease is endemic in Africa, Latin America, and Yemen, imported cases have been described in the United States. The causative organism, Onchocerca volvulus, is transmitted by the bite of a black fly of the genus Simulium. There are a number of cutaneous manifestations of the disease, including onchocercomas, which are subcutaneous bundles of worms. The antiparasitic agent ivermectin is the drug of choice for both prophylaxis and treatment of active disease.

Cutaneous onchocerciasis

Onchocerciasis was diagnosed when a skin biopsy specimen immersed in saline revealed microfiliariae. The patient was a 22-year-old student from Cameroon, West Africa, complaining of small, recurrent, pruritic papules on his thighs. Chemotherapy with ivermectin, an established antiparasitic agent with newly recognized anti-onchocercal potential, was well tolerated, and microfilariae were not detected in post-therapy skin biopsy specimens. The diagnosis of onchocerciasis should be entertained in individuals returning or emigrating from endemic areas.