“Skin writing” – aka dermatographism/dermographism

An example of dermatographism. courtesy of Wikipedia user R1carver

For some people, scratching the skin leads to raised wheals, demonstrating dermatographism which literally means “skin writing.” Scratching or stroking the skin leads to redness and a wheal of that area. About 5% of the population develops redness and some swelling of scratched areas — this is called simple dermatographism. In symptomatic dermatographism, these areas become itchy as well and the wheals are more prominent. In general, wheals develop about 5-10 minutes after the scratching but sometimes they can develop after a longer period of time. Your doctor can test whether you have dermatographism by gently scratching your skin (

usually your back) and seeing whether a wheal forms.

If you have dermatographism, try to avoid stimuli like scratching which lead to the discomfort. Antihistamines can also offer symptomatic relief.