Interdigital skin lesions of the lower limbs among patients with lymphoedema in an area endemic for bancroftian filariasis

OBJECTIVES An estimated 15 million persons suffer from lymphoedema of the leg in filariasis-endemic areas of the world. A major factor in the progression of lymphoedema severity is the incidence of acute dermatolymphangioadenitis (ADLA), which is triggered by bacteria that gain entry through damaged skin, especially in the toe web spaces ('interdigital skin lesions'). Little is known about the epidemiology of these skin lesions or about patients' awareness of them. METHODS We interviewed and examined 119 patients (89% women) with lymphoedema of the leg in Recife, Brazil, an area endemic for bancroftian filariasis. RESULTS We detected 412 interdigital skin lesions in 115 (96.6%) patients (mean, 3.5 lesions per patient, range 0-8). The number of interdigital skin lesions was significantly associated with lymphoedema stage (P < 0.001) and frequency of ADLA (P < 0.0001). Only 20 (16.8%) patients detected their own interdigital skin lesions or considered them abnormal. Patients reported a mean of 3.6 ADLA episodes during the previous 12 months (range, 0-20); reported ADLA incidence was associated with lymphoedema stage (P < 0.0001) and the number of interdigital skin lesions detected by the examining physician (P < 0.0001). CONCLUSIONS These data suggest that interdigital skin lesions are a significant risk factor for ADLA and that persons with lymphoedema in filariasis-endemic areas are unaware of their presence or importance. Prevention of ADLA through prompt recognition and treatment of interdigital skin lesions will require that patients be taught to identify lesions, especially between the toes and to recognize them as abnormal.