Histoid Leprosy: Case Series from Non-Endemic Region in Post-Elimination Era

Histoid leprosy (HL) is a rare variant of lepromatous leprosy (LL) with unique histopathological findings and a characteristic bacterial morphology. HL occurs in highly bacilliferous patients such as LL or borderline LL and indicates the reservoir of infection. We report the clinical, histopathological and bacteriological features of three patients with de novo HL. The patients presented with asymptomatic skin papules on the face and trunk over a couple of years. Their past medical and family history was noncontributory. There were multiple, discreet, shiny, dome-shaped, skin-coloured to erythematous papules and nodules are seen on the face, trunk and extremities. Slit skin smeared showed the bacteriological index of 5+. Skin biopsy was done, and histopathology revealed a sub-epidermal grenz zone under atrophic epidermis and a collection of histiocytes in a whorled pattern in the dermis. A few macrophages are seen in the dermis. One of our cases presented with type 2 lepra reaction after completion of antileprosy treatment. Occurrence of de novo cases of HL from a non-endemic area may pose problems of missing/delay in the diagnosis and threat in the process of eradication of leprosy. It raises the question of the efficacy of conventional duration of multidrug therapy in some of such patients, thus necessitating studies to closely monitor or follow-up these cases for relapse or transmission of disease among close contacts and measures to control them.