[Erythema induratum of Bazin associated to Mycobacterium tuberculosis infection]

Erythema induratum of Bazin is uncommon in children. We report the case of a 12 year-old girl from China, referred by her pediatrician with long lasting lesions of erythema nodosum and a positive tuberculin skin test (20 mm). She had no other symptoms. Physical examination showed purple nodular lesions located on both legs, mostly on the pretibial areas but also on her calves. A chest X-ray was normal. A skin biopsy was obtained, showing granulomata and septolobular panniculitis. Attempts to identify Mycobacterium tuberculosis by culture and PCR were negative. M. tuberculosis was isolated in one of three gastric aspirate samples. She was treated with isoniazid, rifampin, pyrazinamide and ethambutol. There was complete remission of the lesions. This case highlights the importance of considering erythema induratum in atypical cases of erythema nodosum and the need to perform a thorough investigation in search of active tuberculosis.