Diseases & Conditions

Dermatographia

Dermatographia is a condition in which lightly scratching your skin causes raised, red lines where you've scratched. It's not serious, but it can be uncomfortable. In dermatographia, your skin cells are overly sensitive to minor injury, such as scratching. Signs and symptoms of dermatographia include redness, itching and swelling similar to hives.

In most cases, dermatographia symptoms go away in a short time, and you don't need treatment. But if symptoms are severe or bothersome, your doctor may suggest taking antihistamines. Simple self-care measures also can help you manage this skin condition.

Other than raised red lines, dermatographia often causes no problems. In some people, however, scratching or rubbing the skin may cause uncomfortable irritation.

Symptoms of dermatographia may include:

• Raised red lines
• Swelling
• Inflammation
• Hive-like welts
• Itching

Simple things can trigger symptoms of dermatographia. For example, rubbing from your clothes or bedsheets may irritate your skin. Cold, heat, pressure, sunlight and emotion also can trigger dermatographia.

You may notice symptoms of dermatographia within a few minutes of your skin being rubbed or scratched. The symptoms may last 30 minutes to a couple of hours, but typically fade within 15 minutes after the irritation to your skin ends. Rarely, dermatographia develops slowly and lasts several hours to several days and causes burning and pain.

The exact cause of dermatographia isn't clear. It may be caused by an allergic response, yet no specific allergen has been identified.

See your doctor if you have signs of dermatographia such as skin redness and swelling that recur frequently or don't go away on their own. If your symptoms are severe and very uncomfortable, you may need treatment.

Your doctor can diagnose dermatographia with a simple test. He or she will draw a tongue depressor across the skin of your arm or back. If a red, swollen line or a welt (wheal) appears within a few minutes, you may have dermatographia.

To help find out what's causing your dermatographia, your doctor may ask you to keep a detailed diary of exposure to possible allergens over a period of two weeks to a month and a record of when dermatographia signs occur. Your doctor may also recommend skin testing for allergies.

Because dermatographia may be triggered by many different things and because it can be aggravated by stress and other emotions, it's sometimes difficult — even impossible — to determine the cause.

Dermatographia generally is harmless. It leaves no lasting marks and often causes only minor symptoms. However, dermatographia can be uncomfortable. If it's linked to allergies, determining what you're allergic to may help. If dermatographia is a problem for you, work closely with your doctor to manage it.

In many people, the condition gets better over time, although it can be unpredictable.

Symptoms of dermatographia usually go away on their own, and treatment for dermatographia generally isn't necessary. However, if the condition is severe or bothersome, your doctor may recommend antihistamine medications. These drugs block histamine, an inflammatory chemical released by your immune system during an allergic reaction. A low dose of antihistamine usually provides relief at the time of the reaction. You might need to take medication on a regular basis if your symptoms are severe.