A child presents with grouped papulo-vesicular lesions on the face that ulcerate, forming tuberculid-like lesions. He has strongly positive Mantoux test and the lesions resolve spontaneously leaving depressed scars. There is no active internal TB. This condition is:

• A Lupus vulgaris
• B Lichen scrofulosorum
• C Papulonecrotic tuberculid (PNT) ✓
• D Erythema induratum of Bazin

Explanation

Papulonecrotic tuberculid (PNT) presents with symmetrically distributed grouped papules that undergo central necrosis and ulceration, healing with depressed scars — typically on the face, extensors of limbs. It is a tuberculid (hypersensitivity reaction to MTB antigens in a sensitized host) with no demonstrable bacilli in lesions and strongly positive Mantoux. Lichen scrofulosorum presents as grouped lichenoid follicular papules around hair follicles and sweat glands. Erythema induratum (Bazin) presents as indurated nodules on calves that ulcerate, associated with TB. Lupus vulgaris shows apple-jelly nodules.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.