Human T-cell lymphotropic virus type 1 infective dermatitis emerging in adulthood.

Background: Infective dermatitis (ID) is a rare dermatologic condition of childhood that has been linked to human T-cell lymphotropic virus type 1 (HTLV-1).

Objective: To analyze the clinical and laboratory features associated with adult-onset ID linked to HTLV-1.

Methods: From December 1995 to December 2007, four patients with ID were followed in the dermatology outpatient clinic of the "Hospital das Clínicas" of the University of São Paulo Medical School, São Paulo, Brazil. Epidemiologic data were collected and dermatologic examination was performed. Patients were submitted to histopathologic, hematologic, virologic, and immunologic investigations.

Results: All patients had a diagnosis of ID according to previously established criteria, despite being adults. HTLV-1 infection was demonstrated by enzyme-linked immunosorbent assay, Western blotting assays, and polymerase chain reaction. The male to female ratio was 1 : 3 and the median age at diagnosis was 42 years. The cutaneous manifestations were erythematous, scaly, and crusted lesions in all patients, and ichthyosis in three of the four cases. Histopathologic study showed lymphocytic epidermotropism in two cases. The median proviral load was 281 copies/10,000 peripheral blood mononuclear cells. Immunodeficiency was not observed in any case. The therapies used were antimicrobials, corticosteroids, and phototherapy.

Conclusions: Although many authors have considered ID to be a form of childhood dermatitis, we have described four cases that fulfilled the major criteria for ID, except for onset in adulthood.