[Cutaneous tuberculosis of the ear due to Mycobacterium bovis]

Isolated cutaneous tuberculosis is uncommon, accounting for only 0.14 to 5% of Mycobacterium tuberculosis infections. We report a rare case of ear cutaneous tuberculosis due to Mycobacterium bovis in an immunocompetent woman.

A 59-year-old woman presented an erythematous and scaly lesion of the ear present for two years. The histological findings were compatible with a diagnosis of sarcoidosis, with non-necrotic granuloma. After failure of dermal corticosteroid therapy, a further biopsy identified M. bovis; the patient was cured following anti-tubercular treatment.

Ear lesions are predominantly associated with tumors, fungal infections, chondritis, lupus and sarcoidosis. The ear, like the face in general, is a classic localization of lupus vulgaris, a chronic form of confined tuberculosis infection with progressive evolution. The paucibacillary nature of these lesions is the reason why their diagnosis is based in some cases on clinical, histological and immunological findings without bacteriological evidence. However, given the potential therapeutic implications, it is important to push the microbiological analysis as far as possible. In our case, culture and identification provided evidence of M. bovis infection, enabling suitable and effective therapy to be given.