a local exacerbation reaction occurring in Lucio leprosy . Initially there is ischemic necrosis of the epidermis due to necrotizing vasculitis of small blood vessels of the subpapillary plexus; next, small erythematous lesions erupt and have central necrosis; later, if the eschar is shed, ulceration can be seen, with eventual scar formation. Cf. erythema nodosum leprosum .