Onchocerciasis presenting with lower extremity, hypopigmented macules

Onchocerciasis, or river blindness, is a parasitic infection caused by the filarial nematode, Onchocerca volvulus. It infects 18 million people worldw ide, but is rarely seen in the United Stales. it is one of the leading caus es of blindness in the developing world. Although onchocerciasis is also kn own as river blindness, it is not just a disease of the eyes, but rather a chronic multisystem disease. Clinically, onchocerciasis lakes three forms, 1) eye disease, 2) subcutaneous nodules; and 3) a pruritic hy popigmented o r hyperpigmented papular dermatitis. We present an 18-year-old African fema le with a 5-year history of asymptomatic, hypopigmented, slightly atrophic macules on her anterior tibiae. Pathology revealed a scant perivascular inf lammatory infiltrate with mononuclear cells, eosinophils, and rare microfil ariae in the papillary dermis. Ivermectin is the treatment of choice for on chocerciasis and was initiated in this patient. We present this interesting patient with onchocerciasis to expand our differential of hypopigmented ma cules, especially in the African population. In addition, we discuss both t he diagnosis and the treatment of onchocerciasis in expatriate patients liv ing in nonendemic areas.