A 6-year-old girl presents with discrete, grouped, firm, skin-coloured follicular papules over the chest and abdomen of 2 months' duration. There is no ulceration or discharge. Chest radiograph shows hilar lymphadenopathy and the Mantoux test is strongly positive. The most likely diagnosis is:

• A Papular urticaria
• B Keratosis pilaris
• C Lichen scrofulosorum ✓
• D Lichen nitidus

Explanation

Lichen scrofulosorum is a tuberculid seen in children with underlying tuberculosis elsewhere, presenting as grouped, tiny, firm, follicular or lichenoid papules usually on the trunk. Histology shows superficial epithelioid cell granulomas around hair follicles and sweat ducts without caseation. Strongly positive Mantoux and evidence of visceral or nodal tuberculosis support it, and lesions clear promptly with antitubercular therapy. Keratosis pilaris and lichen nitidus lack this systemic association.

Reference: Rook's Textbook of Dermatology, 9th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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