Papulonecrotic tuberculid in children. A report of eight patients.

Papulonecrotic tuberculid (PNT), a form of cutaneous tuberculosis (TB), is uncommon in children. We identified eight children (six girls and two boys) with PNT. Their ages ranged from 19 to 139 months (median 47.5 months, mean:64.75 months). Skin lesions had been present for 2-24 weeks (median: 4 weeks) before diagnosis. All patients displayed scattered papulo- and/or pustulonecrotic lesions on the limbs, and the ears were involved in six patients. Lesions healed with varioliform scars. Associated pulmonary TB was present in seven patients. Additional clinical findings included fever (n = 4), hepatomegaly (n = 4), lymphadenopathy (n = 3), phlyctenular conjunctivitis (n = 3), and splenomegaly (n = 2). Histology of eight biopsies showed ulceration (n = 6), dermal necrosis (n = 6) (follicle-centered in two), granulomatous inflammation (n = 6) (palisading granuloma-like in three), superficial and deep infiltrate of lymphocytes (n = 7), erythrocyte extravasation (n = 7), and subepidermal edema (n = 3). Vasculitis was not a feature. A Ziehl-Neelsen stain was negative in all. Glycosaminoglycans were not increased. Immunohistochemistry found a predominance of T lymphocytes, macrophages, a few antigen-presenting cells, and no B lymphocytes, consistent with a type IV hypersensitivity reaction. Polymerase chain reaction (PCR) performed on deparaffinized tissue identified M. tuberculosis DNA in one biopsy. All patients received combination anti-TB treatment for 6 months. Six patients were compliant and were followed up for 6-30 months. Skin lesions and pulmonary TB healed in all. PNT in children resembles the adult form, but phlyctenular conjunctivitis and associated TB are more common, scrofuloderma and concomitant erythema induratum of Bazin are unusual, and vasculitis is not found. In cases where M. tuberculosis DNA can be confirmed with PCR, papulonecrotic TB is perhaps the more appropriate nomenclature.