Mees Lines — SCE Dermatology MCQ

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ModerateNail DisordersMees LinesSCE Dermatology

A 65-year-old man presents with nail changes. He has transverse white bands that move distally with nail growth. Each band corresponds to a previous chemotherapy cycle. What are these nail changes called?

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Correct answer: C — Mees lines (transverse true leukonychia)

Mees lines are transverse white bands of true leukonychia (discolouration within the nail plate itself — they move distally with nail growth). They result from temporary disruption of nail matrix keratinisation during systemic insults. Classic causes include: chemotherapy cycles (each cycle producing a band), heavy metal poisoning (arsenic, thallium), severe systemic illness, and renal failure. Mees lines must be distinguished from Muehrcke lines (apparent transverse white lines that do NOT move with nail growth — they represent nail BED changes, typically from hypoalbuminaemia, and disappear with nail plate compression). Beau lines are transverse depressions (not white bands).

Reference: BAD 2016 Nails; Medicine Review