Dermographism is a common form of chronic hives. It is also known as "skin writing". Dermographism is the most common form of a subset of chronic hives known as physical hives. It occurs in some degree in about 5% of the population
Appearance
People with dermographism experience a linear, itchy hive within minutes of stroking the skin with an object. This is in contrast to the linear reddening that does not itch seen in healthy people who are scratched. The hives appear within minutes and resolve within hours.
Cause
The tendency to be "dermographic" lasts for weeks to years. In most cases the cause is unknown, although it may be preceded by a viral infection, antibiotic therapy, or emotional upset.
Diagnosis
Dermographism is diagnosed by taking a tongue blade and drawing it over the skin of the arm or back. The hives should develop within 1 to 3 minutes.
Treatment
Unless the skin is highly sensitive and reacts continually, treatment is not needed. Taking antihistamines can reduce the response in cases that are annoying to the patient.
