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Beau's lines
System: Skin & Nail Signs · All skin & nail signs
What it is — and how it is elicited
A horizontal groove or ridge running across a nail, which moves outward as the nail grows, dating the illness that caused it.
What a positive finding suggests
Associated with a period when nail growth was interrupted — severe illness, high fever, chemotherapy or major stress.
◈ Behind the name
Joseph Honoré Simon Beau (1806–1865), French physician.
Related signs — Skin & Nail Signs
Browse the B section of the A–Z list or return to the Clinical Signs hub.
Please note: This page is an educational reference about clinical examination signs. A clinical sign supports — and never replaces — a full clinical evaluation, examination and appropriate testing. A sign being present does not by itself prove a diagnosis, and an absent sign does not rule one out. If you have symptoms that worry you, see a health professional.