Dermatographism

Dermatographic urticaria (also known as dermographismdermatographism or “skin writing“) is a skin disorder seen in 4–5% of the population and is one of the most common types of urticaria,in which the skin becomes raised and inflamed when stroked, scratched, rubbed, and sometimes even slapped.

The symptoms are thought to be caused by mast cells in the surface of the skin releasing histamines without the presence of antigens, due to the presence of a weak membrane surrounding the mast cells. The histamines released cause the skin to swell in the affected areas. Self-referential illustration of dermatographic urticaria.

This weak membrane easily and rapidly breaks down under physical pressure causing an allergic-like reaction, generally a red weal (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 weal to appear. These weals are a subset of urticaria (hives) that appear within minutes, accompanied by a sensation of burning, and itchiness. The first outbreak of urticaria can lead to others on body parts not directly stimulated, scraped or scratched. In a normal case the swelling will reduce itself with no treatment within 15–30 minutes, but in extreme cases, itchy red weals may last anywhere from a few hours to days.


Ariana Page Russell, Index, 2005.  (link)     Image above from collabcubed.com (link)

Link to artist who uses her dermatographism as her medium Ariana Page Russell (and here)

 

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