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Koebner phenomenon
System: Skin & Nail Signs · All skin & nail signs
What it is — and how it is elicited
New lesions of a person's existing skin disease appear in lines or patches of previously normal skin that has been scratched, rubbed or injured.
What a positive finding suggests
Associated with psoriasis, lichen planus and vitiligo, among other skin diseases.
◈ Behind the name
Heinrich Koebner (1838–1904), German dermatologist.
Related signs — Skin & Nail Signs
Browse the K 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.