A 55-year-old male presented with recurrent crops of crusted papular lesions on extensor surface of upper limbs and back for 1month and boils over buttocks for 20 days. He also gave history of productive cough for 15 days and occasionally he coughed out blood-tinged sputum. On examination, multiple papules with crusting and central necrosis were seen on bilateral extensor surface of upper limbs with clustering of lesions around elbows and the back [Figures 1 and 2]. Few nodules with central necrosis were seen on buttocks and scalp. One ulcer of size 4x4cm with necrotic base and surrounding erythema were seen on left buttock [Figure 3].
Investigations revealed raised ESR 55 mm/h (Westergren), with evidence of tuberculosis on chest X-ray in bilateral lung fields. His Mantoux was strongly positive with induration of 20 mm. Sputum for AFB was positive. Biopsy from the lesion on the right elbow revealed a single focus of leucocytoclastic vasculitis affecting a small- to medium-sized vessel in mid-dermis. Surrounding this focus was dense neutrophilic inflammation. Upper dermis showed large subepidermal pustule with marked edema. There was no granuloma. These features were consistent with PNT [Figures 4 and 5]. Rest of the investigations like complete blood count, liver function tests and renal function tests were within normal limits.
Patient was started on multidrug therapy (MDT) consisting of rifampicin 600 mg, isoniazid 300 mg, pyrazinamide 1500 mg, and ethambutol 800 mg. On starting therapy, many lesions on back disappeared within 2weeks. His general condition has improved and at 4weeks of therapy, he has no cough. He is still on MDT and his skin lesions are healing with scarring.