Erythema Nodosum Caused by Mycobacterium tuberculosis in HTLV-1 Infected Patients

HTLV-1 infection has a worldwide distribution but the majority of patients infected by the virus are in Africa, Central and South American and in the Southern of Japan [1]. The HTLV-1 associated myelopathy or tropical spastic paraparesis (HAM/TSP) and Adult T-cell leukemia (ATL) are the main diseases related to the virus but they occur in less than 5% of infected subjects [2]. However, nowadays it is known that a large number of diseases and syndromes such as sicca syndrome, uveitis, HTLV-1 associated Arthropathy, chronic periodontitis, overactive bladder and erectile dysfunction have been related to HTLV-1 [3-5]. Moreover, HTLV-1 increases the susceptibility and modifies the clinical presentation of other infectious diseases such as helminths infections [6,7] tuberculosis [8] and fungal infections [9,10]. In countries where both tuberculosis and HTLV-1 are endemics, the association between these two diseases is highly relevant, as HTLV-1 increases in 2-4 fold the risk for tuberculosis [8,11]. It is not clear if HTLV-1 influences the severity of tuberculosis or the appearance of extra pulmonary tuberculosis, but there are more death among tuberculosis patients co-infected with HTLV1 [12] and extra pulmonary tuberculosis have been reported in a few HTLV-1 infected subjects [13]. Erythema nodosum is characterized by nodular erythematosus lesions predominantly in the lower limbs.