Ulnar nerve abscess and relapse in a patient with indeterminate leprosy 1 year after completion of multidrug therapy.

The introduction of multidrug therapy has efficiently controlled leprosy in developing countries. However, Mycobacterium laprae may survive and cause relapse despite adequate treatment with antileprosy drugs. Relapse may be characterized by a combination of new signs or symptoms and presence of acid-fast bacilli on skin or nerve biopsy samples. We report a case of a child in whom ulnar abscess developed 12 months after successful completion of multidrug therapy with clinical and histopathological evidence of relapse.