Thalidomide-induced leukocytoclastic vasculitis in leprosy

Thalidomide has become the gold standard for the treatment of erythema nodosum leprosum (ENL) within a few decades of its serendipitous discovery for this condition. It has also demonstrated efficacy in dermatoses such as recalcitrant oral aphthae, prurigo nodularis, and pyoderma gangrenosum. Despite a good safety profile, thalidomide is known to cause side effects such as sedation, constipation, peripheral neuropathy, and thromboembolism. Although rare and anecdotal, adverse cutaneous drug reactions (ACDRs) have been reported. Both thalidomide and its newer analogs have been implicated for maculopapular, urticaria-angioedema, Steven–Johnson-like, toxic epidermal necrolysis, and acneiform eruptions. Only a few cases of leukocytoclastic vasculitis (LCV) occurring in patients of multiple myeloma on this drug have been described till date. However, this unusual presentation of ACDR due to thalidomide in leprosy has not been hitherto documented. Herein, we describe a patient of lepromatous leprosy with ENL who developed thalidomide-induced LCV and discuss myriad aspects such as immunopathogenesis with emphasis on the possible role of various cytokines such as interleukin (IL)-2, IL-6, IL-12, and tumor necrosis factor-alpha.