OverviewDermatographism is a condition where lightly scratching the skin raises wheals or welts. Histamine is released at the site, causing the small blood vessels (capillaries) to dilate, producing redness and localized swelling.
Update Date 5/6/2012
Updated by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Stuart I. Henochowicz, MD, FACP, Associate Clinical Professor of Medicine, Division of Allergy, Immunology, and Rheumatology, Georgetown University Medical School. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.