Have you ever heard of it? I hadn't until pretty recent. Here is the definition from the Wikipedia:
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 urticariaThis weak membrane easily and rapidly breaks down under physical pressure causing an allergic-like reaction, generally a red wheal (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 wheal to appear. These wheals 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 wheals may last anywhere from a few hours to days.
Scratching on the skin with a dull object can produce Dermographism.It has been reported that one artist with dermatographism uses her skin as her medium.
Causes
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 and is not contagious (transferable to other persons).
Symptoms can be induced by stress, tight or abrasive clothing, watches, glasses, energetic kissing, heat, cold,[4] or anything that causes stress to the skin or the patient. In many cases it is merely a minor annoyance, but in some rare cases symptoms are severe enough to impact a patient's life.
Treatment
Dermographism can be treated by antihistamines which prevents the histamine from causing the reaction, and these may need to be given as a combination of H1 antagonists, or possibly with an H2-receptor antagonist such as cimetidine.[5][6]
Not taking hot baths or showers may help if it is generalized (all over) and possibly for localized (in a specific area). If not taking showers helps, it may be a condition called shower eczema. If it mainly affects the head it may be psoriasis. In rare cases, allergy tests may uncover substances the patient is allergic to. Using biodegradable or hypo-allergenic soaps and laundry supplies may help.
While cromoglycate, which prevents histamine from being released from mast cells, is used topically in rhinitis and asthma, it is not effective orally for treating chronic urticaria.
Acupuncture and Chinese herbs have long been used to treat urticaria in the Asian world. Results of clinical trials of both acupuncture and Chinese herbs are numerous and suggest a potential remedy for acute urticaria but these are far from conclusive and likely a result of the placebo effect, as they did not provide a control group.
Wow, sounds like a whole lot of jargon to me.... Basically about 8 months ago or so I started to notice that my skin would get really itchy, I would scratch, and wherever I scratched my skin would swell up and it would turn bright red, and it would get real warm and kind of a burning sensation. My scalp even got really itchy, like drive me crazy itchy (obvioiusly I assume dry scalp) I figured it was a laundry detergent allergy so we switched back to one I have used in the past. No change. Actually got a little worse perhaps, coworkers would ask why my neck ( or some other random part of me ie: arm, leg etc..)was so red. I really didnt know. So after some time and some mega irritation I started doing research. My mom actually told me about skin writers so I looked it up and all symptoms fit. I have since then seen a dermatologist and been put on antihistamines.Now I am not itchy at all usually , including scalp, but I am sad that when I do write on my arms etc.. it doesn't show as good or stay as long. That part about all this was great, my kids liked to see it.
Here are a couple pics.. not the greatest.
