What should you know about dermatographia hives?

Dermatographia is a form of inducible urticaria, also called hives. Mechanical stimulation makes skin cells release chemical signals, producing a linear welt that can itch, burn or feel warm. The mark often follows the shape of a scratch, seam or fingernail rather than appearing randomly. A clinician can often recognise it from the history and the pattern on examination.

It is different from an infection because the raised line follows contact and may fade without antibiotics. Episodes can be aggravated by heat, tight clothing, friction, emotional stress or dry skin, although a single trigger is not always found. Facial or deeper swelling can occur with hives and needs separate attention.

Use a gentle cleanser and fragrance-free moisturiser, keep showers comfortably warm rather than hot, and choose loose soft clothing. Pat instead of rubbing the skin and keep nails short. Note what touched the area, how quickly marks appeared and how long they lasted. A clinician may discuss an oral antihistamine for recurring symptoms; do not change doses or combine products without advice.

Read about [Hives](/conditions/urticaria/), [Itchy Skin](/symptoms/itchy-skin/) and [Antihistamine Treatment](/treatments/medical-dermatology/oral-antihistamine-therapy/).

Seek urgent help for swelling of the lips, tongue or throat, trouble breathing, faintness or difficulty swallowing. These may signal a serious allergic reaction. Arrange a medical review when hives persist, disrupt sleep, leave bruising, or occur with fever, joint pain or unexplained swelling. See [Angioedema](/conditions/angioedema/) and [Skin Swelling](/symptoms/skin-swelling/) for related symptoms.

Ask whether the pattern fits dermatographia, whether a medicine or product could be contributing, which antihistamine is suitable, and what symptoms should trigger emergency care. If severe flares have occurred, ask when additional treatment is appropriate.