Dermatographic urticaria

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**Dermatographic urticaria**
*Classifications and external resources*
ICD-10	L 50.3
ICD-9	708.3
OMIM	125635
DiseasesDB	12736
eMedicine	derm/446

Dermatographic urticaria (also known as dermographism, dermatographism or"skin writing")is a skin disorder seen in about 5 percent of the population,in which the skin becomes raised and inflamed when touched, even lightly. Dermatographic urticaria is caused by mast cells in the surface of the skin releasing histamines due to the presence of a weak membrane surrounding the mast cells. The histamines released cause the skin to swell in the affected areas.

This weak membrane easily and rapidly breaks down under physical pressure causing an allegic-like reaction, generally a red welt to appear on the skin. It can often be confused with an allergic reaction to the object causing a scratch, when in fact it is the act of being scratched that causes a welt to appear. These wheals are a subset of hives that appear within minutes, accompanied by a sensation of burning, and/or itchiness. The redness and swelling stays from anywhere upwards of 10 minutes. Often this leads to difficulty sleeping, irritability, and general discomfort.

It can be treated by antihistamines or cromoglicate, as they prevent the histamine from causing the reaction. The underlying cause of dermographism is not known, and can last for many years without relief. 95% of chronic cases are never solved. Sometimes the condition goes away, sometimes it stays forever. It is not a life threatening disease.