Background: Human T cell lymphotropic virus type 1 (HTLV-1)-associated infective dermatitis (IDH) is a chronic and recurrent eczema occurring during childhood and adolescence. HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a chronic myelopathy of adulthood, presenting with slowly progressive spastic paraparesis and sphincter dysfunction with mild sensory involvement. There are few reports describing an association between IDH and HAM/TSP. The objective of this study was to evaluate the occurrence of HAM/TSP in patients with IDH and in seropositive members of their families and to determine the blood levels of antibodies against HTLV-1 in patients with HAM/TSP.
Methods: Twenty patients with IDH and their seropositive mothers and siblings underwent clinical, neurological, and laboratory evaluations. The diagnosis of HAM/TSP was made in accordance with the World Health Organization criteria.
Results: Nine individuals had HAM/TSP (6 of the patients with IDH, 2 mothers, and 1 seropositive brother). In 3 families, > 1 individual had HAM/TSP. The serum antibody titers of the patients with HAM/TSP varied from 1 : 3.125 to 1 : 78.125.
Conclusions: A strong association was observed between IDH and HAM/TSP. The familial clustering of both diseases suggests a genetic background. Serological screening for HTLV-1 in children with symptoms of myelopathy is essential in areas where HTLV-1 is endemic.