Leprosy: a 'common' and curable cause of peripheral neuropathy with skin lesions.

Leprosy (or Hansen's disease) is a curable chronic infectious disease caused by the acid-fast bacillus Mycobacterium leprae. While leprosy remains one of the most common causes of neuropathy worldwide, its rarity in the UK means that many doctors are unfamiliar with the typical clinical features. This is problematic because early recognition and treatment is vital in order to minimise disease-related complications such as nerve injury. We describe a 75-year-old man who presented with multiple mononeuropathy (mononeuritis multiplex, particularly affecting the ulnar nerves) and typical granulomatous skin lesions, in whom the diagnosis was made on the basis of skin biopsy. We highlight the clinical features, investigations and treatment of the patient, and provide information about the epidemiology and pathogenesis of leprosy.