Effects of Ivermectin Treatment of Sowda (Hyperreactive Onchodermatitis) in Ghanian Patients

Background: Though Onchodermatitis was a public health problem in Ghana, sowda had never been reported there. Sowda patients have been isolated from and forgotten by society. Thus, it was crucial to find out whether sowda was present in Ghana and, if so, to treat these patients with ivermectin and monitor the outcome.

Methods: An active search for patients with sowda was carried out in 16 villages around Hohoe, Volta Region, Ghana. The patients underwent clinical examinations including photographic documentation of their skin lesions. Skin snips were taken and a local Mazzotti test was performed. Blood was drawn for eosinophil count. A single oral dose of ivermectin was administered.

Adverse events were monitored over 3 days. Follow-up was carried out one month later and the above examinations repeated.

Results: A total of 18 patients, 6 males and 12 females, with an age range from 7-60 years were diagnosed to have sowda. The skin lesions were asymmetric (94%) and involved predominantly the gluteal region (89%) and lower extremities (94%). The severely pruritic skin lesions included papules, pustules, lichenification and hyperpigmentation. Onchocercomata were found only in 28% of the patients and 56% had a positive skin snip for microfilaria (median 0.77 mf/mg). A topical Mazzotti test was positive in all cases. The ivermectin administration was associated only with minor and transient adverse events in the first 72 hours. The follow-up one month later revealed significant improvement of the itching and skin lesions. The parasitological tests turned out negative as well.

Conclusion: Sowda is present in Ghana. A single oral dose of ivermectin results in significant clinical and parasitological improvements.