[Nail involvement in leprosy]

Leprosy, a disease caused by Mycobacterium leprae, primarily affects the skin and nerves, but the nails are also involved in as many as 3 out of 4 patients .The factors that trigger nail changes in leprosy are numerous and include repeated trauma, neuropathy, vascular impairment, infections, lepra reactions, and the drugs used to manage the disease. The changes most often reported include subungual hematomas, onycholysis, onychauxis, onychogryphosis, pterygium unguis, and onychoheterotopia, most of which can be attributed to nerve damage and trauma. Furthermore, the acro-osteolysis that occurs in the advanced stages of the disease may present with brachyonychia, racquet nails, or even anonychia. Infections of the nail bed leading to paronychia and onychomycosis should also be taken into account in leprosy. Other typical changes include longitudinal striae, pitting, macrolunula, Terry nails, leukonychia, hapalonychia, and Beau lines. In this review, we describe the principal nail changes associated with leprosy. These changes, which are highly varied and diverse in origin, are in fact a reflection of the significant morbidity caused by M. leprae infection.