Onchodermatitis—correlation between skin disease and parasitic load in an endemic focus in Ecuador

Abstract

Onchocerciasis is a chronic parasitic infection in which infiltration of the skin by microfilariae has been associated with a number of different pathological changes. This survey compared the prevalence of different forms of skin disease in two villages, one of which was located within the endemic zone for onchocerciasis (Zapallo Grande), in a lowland rain forest area of western Ecuador. The commonest skin diseases in both villages were scabies, pyoderma and pityriasis versicolor. In addition changes closely correlated with the presence of microfilariae in skin snips were found in Zapallo Grande--such as atrophic gluteal changes, and acute and chronic papular dermatitis. The only other skin disease associated with onchocerciasis was widespread tinea corporis due to T. rubrum. The Amerindians in the endemic onchocerciasis area were more likely than Negroes to have generalized atrophic changes of the skin, whereas in the latter group significant numbers of individuals had no obvious skin lesions but large numbers of microfilariae were detected in skin snips. Acute papular dermatitis was common in both groups and in biopsied lesions microfilariae could usually be identified within the epidermis or close to the dermo-epidermal junction. One patient had developed severe reactive onchodermatitis (Sowda). Swabs taken from onchocercal skin lesions showed no evidence of skin surface carriage of Staphylococcus aureus. Changes classically associated with onchocerciasis such as pretibial hypopigmentation (leopard skin) and hanging groin were notably absent in this population.

Immumoglobulin allotypes in Ecuadorian Cayapa Indians

“…It has been reported that the frequency of severe dermatological disease is greater in Cayapa compared to blacks living in the same or neighboring villages (Hay et al 1989;Guderian et al 1989). Conversely, the risk of developing chronic eye disease or lymphatic disease from onchocerciasis appears to be greater among the Ecuadorian blacks (Molnea et al 1984).…”

Onchodermal skin disease in a hyperendemic onchocerciasis focus in western Uganda.

“…This confirms findings from other studies which did not find an association between intensity of infection with O. volvulus and skin involvement. 1,10,11 Males had higher skin scores than females. This contrasts with findings from Nigeria where females suffered more often and more severely than males from onchocercal skin disease.…”

Onchozerkose

“…Sie ist mit einer verzö-gerten Immunantwort verbunden,die gewöhnlich bei Patienten mit einer geringen Mikrofilarienlast auftritt. Dagegen zeigen Patienten mit einer hohen Mikrofilarienlast keine immunologischen Phä-nomene [8]. Es wurde gezeigt, dass Th2-Zytokine,einschließlich IL-4 und IL-5,bei der Vermittlung einer Reaktion gegen Filarien eine Rolle spielen [9].…”