Infective dermatitis associated with human T-cell lymphotropic virus type 1: evaluation of 42 cases observed in Bahia, Brazil.

Background: Infective dermatitis associated with human T-cell lymphotropic virus type 1 (HTLV-1; IDH) is a chronic recurrent eczema affecting HTLV-1-infected children. The epidemiological and dermatological characteristics of IDH are described, and their principal diagnostic criteria are reevaluated.

Methods: Forty-two patients were included: 40 patients serologically positive for HTLV-1 and 2 seronegative patients who tested positive in polymerase chain reaction (PCR) assays.

Results: The mean age at onset of the disease was 2.6 ± 2.4 years (range, 2 months-11 years). The mean duration of breast-feeding was 24.2 months. The lesions were erythematous, scaly, and crusted, always affecting the scalp and retroauricular regions. Crusting of the nostrils was observed in 64.3% of the patients. Of the 36 patients followed up, 23 had the active disease. The age at which IDH disappeared in the others was 10-20 years.

Conclusions: The onset of IDH may occur earlier than reported in the literature. The scalp and retroauricular regions are always affected, and lesions are invariably present in ≥3 areas. Crusting of the nostrils cannot be considered an obligatory factor for the diagnosis of IDH. The recurring nature of IDH was a characteristic found in all cases. Patients with classic IDH lesions who are serologically negative should be investigated by PCR. Therefore, the indispensable criteria for diagnosis are (1) presence of erythematous-scaly, exudative, and crusted lesions involving ≥3 areas, including the scalp and retroauricular regions; (2) recurring nature of the lesions; and (3) a finding of HTLV-1 infection by serology or molecular biology.