Dermatographia urticaria is a dermatological medical condition in which the skin becomes raised and inflamed when rubbed, scratched, stroked, or hit. It is thought to be caused by cells on the surface of the skin releasing large quantities of histamine, a neurotransmitter that is released by the body during allergic reactions that causes inflammation. This causes urticaria - hives - to appear on the skin. It is thought that approximately 4 - 5% of the population suffers from dermatographia