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.