IVERMECTIN TREATMENT OF ONCHOCERCAL SKIN-LESIONS - OBSERVATIONS FROM A PLACEBO-CONTROLLED, DOUBLE-BLIND TRIAL IN MALAWI

To determine effects of ivermectin on skin lesions of onchocerciasis, a placebo-controlled, double-blind trial was carried out in the Thyolo highlands of Malawi involving 70 persons over a 32-month period. Asse ssment was made using both a clinical numeric grading system and seque ntial photographs. Among both ivermectin and placebo recipients, there was a significant reduction in both the severity and extent of papula r skin lesions. Persons with edematous or lichenified skin lesions of onchocerciasis who received ivermectin showed significantly more impro vement than those receiving placebo. Twelve months after the placebo g roup received ivermectin their skin lesions were similar to those of t he ivermectin group. Changes were most evident for those persons with more severe skin disease in both the ivermectin and placebo groups. An nual ivermectin treatment for onchocercal skin lesions is probably ina dequate, and treatment three or four times a year may be required, alt hough the optimum regimen has not been established.