A 16-year-old girl has irregular patches of incomplete hair loss on the frontoparietal scalp. Within each patch, hairs are of varying lengths and some show a twisted, coiled appearance close to the scalp. The pull test is negative. Scalp biopsy would most likely show:

• A Peribulbar lymphocytic infiltrate resembling a swarm of bees
• B Endothrix fungal spores within hair shafts
• C Perifollicular lamellar fibrosis with loss of sebaceous glands
• D Trichomalacia, pigment casts and empty follicles ✓

Explanation

Trichotillomania produces patchy loss with hairs broken at different lengths because they are mechanically pulled and twisted. Histology shows trichomalacia, distorted softened shafts, intrafollicular pigment casts and empty follicles, with minimal inflammation. A peribulbar swarm-of-bees infiltrate defines alopecia areata, where exclamation mark hairs and a positive pull test are expected. Lamellar fibrosis indicates a cicatricial alopecia.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.