A bulla (22 mm in diameter) developed 4 days after a PPD injection (Figure, A and B). The erythema extended, covering almost all the volar forearm, from the elbow down to the wrist (black mark in Figure, A). The full thickness of the skin covering the bulla dislodged 2 days later, with granulation tissue and some yellowish eschar left (Figure, C on day 7 postinjection). Vancomycin hydrochloride was administered empirically for 2 days to treat presumed cellulitis. Cultures of blood and swab tests from the base of the bulla were negative for microorganisms. A biopsy specimen of the right cervical lesions revealed granulomatous inflammation, caseous necrosis, multinuclear giant cells, and acid-fast bacilli suggestive of mycobacterial infection. The patient was treated with isoniazid, rifampin, ethambutol hydrochloride, and pyrazinamide for 2 months followed by isoniazid and rifampin for an additional 4 months. Several tiny cervical lymph nodes remained palpable.