HTLV-1-associated infective dermatitis (HAID) is the main paediatric manifestation of human T-cell lymphotropic virus type 1 (HTLV-1). It is characterised by a chronic exudative eczematous eruption and persistent infection with Staphylococcus aureus (SA) and beta-haemolytic streptococci (BHS). Prevalence is highest in the Caribbean and Brazil; however, cases have been reported in other HTLV-1 endemic regions. Approximately 20 million people worldwide are infected with HTLV-1 and only 5-10% suffer from disease. Treatment options are limited to prolonged antibiotic therapy. The aim of this paper is to review existing evidence and propose new theories on the pathogenesis of HAID. The current view is that HTLV-1 infection is required and in susceptible individuals leads to immune dysregulation with subsequent immunosuppression and superinfection with SA and BHS. Evidence suggests that host, environment and genetic factors may play a causative role. (PMID: 23163646).