Upper extremity swelling and hyperpigmentation due to onchocerciasis in an American

An American woman who had lived in Equatorial Guinea was seen in the United States with intermittent swelling, pruritus, hyperpigmentation, and mild cutaneous atrophy of the right arm. Filarial diseases were considered in the differential diagnosis; skin snips subsequently revealed Onchocerca volvulus microfilariae. There was no evidence of ocular involvement. The case illustrates the importance of obtaining a history of international travel, the need to consider "exotic" parasitic diseases in travelers returning from the tropics, and several of the presenting features of onchocerciasis. In the past, onchocerciasis was treated with diethylcarbamazine and suramin, both of which have appreciable toxicity. A major recent advance has been the introduction of ivermectin, which appears to be more effective and less toxic, and is currently undergoing clinical evaluation in the United States and abroad.