A child with cervical lymphadenopathy develops a discharging sinus over the neck with undermined edges and non-healing ulceration overlying a cold abscess. Biopsy shows caseating granulomas and Ziehl-Neelsen stain is positive. What is the diagnosis?

• A Scrofuloderma ✓
• B Lupus vulgaris
• C Tuberculosis verrucosa cutis
• D Metastatic tuberculous abscess

Explanation

Scrofuloderma results from direct extension of tuberculosis from an underlying focus, most commonly cervical lymph nodes, to the overlying skin. It presents as a firm nodule that breaks down to form an ulcer with undermined edges and bluish-red overhanging skin margins, eventually resulting in a cord-like scar on healing. The ZN stain positivity and biopsy findings confirm the mycobacterial etiology. Lupus vulgaris, by contrast, does not arise from underlying lymph node disease.

Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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