What is dermatographism?
Dermatographism is a common, benign skin condition. People who have this condition develop welts or a localized hive-like reaction when they scratch their skin. It can also happen when the skin is exposed to pressure or rubbing. This condition is also called skin writing, dermographia, or dermatographic urticaria.
How common is dermatographism?
Dermatographism affects about 2% to 5 % of the general population.
What are the causes of dermatographism?
Dermatographism is most likely caused by an inappropriate release of histamine in the absence of a typical immune signal. The red welts and hives are caused by the local effects of histamine.
Other causes include:
- Cold exposure
A person with dermatographism may also have an allergy to an external substance. However, this is uncommon.
What are the symptoms of dermatographism?
The symptoms of dermatographism vary from person to person. Symptoms of dermatographism include:
- Raised red lines
- Hive-like welts