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Alopecia Universalis — SCE Dermatology MCQ

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HardHair DisordersAlopecia UniversalisSCE Dermatology

A woman develops diffuse hair breakage after repeated chemical straightening and high-temperature styling. Trichoscopy shows white nodes; microscopy shows longitudinal cortical splitting with two frayed brush ends opposed at each node. What is the best diagnosis and initial management?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: C — Acquired trichorrhexis nodosa; stop traumatic hair practices and institute gentle conditioning

Explanation lettering: D = shown as A · E = shown as D · A = shown as E

C is correct. Acquired trichorrhexis nodosa is a weathering injury in which cuticular failure and cortical fraying produce pale nodes and the characteristic appearance of two paintbrushes pushed together. Removing chemical, thermal and traction injury, minimising manipulation and using conditioning care allow undamaged new shaft to grow; medicine cannot repair the already fractured segment. Pili torti shows flattened shafts twisted on their axis and may accompany inherited syndromes. Trichorrhexis invaginata has ball-and-socket invagination and supports Netherton syndrome in the appropriate ichthyotic-atopic phenotype. Monilethrix produces regular beading with narrow fragile internodes, while pili annulati produces alternating light and dark bands from air-filled cavities rather than brush fractures.

Reference: DermNet hair-shaft defects review: https://dermnetnz.org/topics/defects-of-the-hair-shaft