Trauma may release an antigen that interacts with the membrane-bound immunoglobulin E of mast cells, which
release inflammatory mediators, particularly
histamine, into the tissues. This causes small blood vessels to leak, allowing fluid to accumulate in the skin
It can be treated by antihistamines or cromoglicate and sometimes steroids, as they prevent the histamine from causing the reaction. As the underlying cause of dermographism is not known, it can last for many years without relief.