Dermatographia is a skin condition that produces bumps, or inflammation, on your skin after you scratch it. Dermatographia is not fully understood, but it appears to be some type of allergic response, the Mayo Clinic says. Often it's not a serious condition and doesn't require medical treatment.
You may experience red, raised lines or hive-like welts on your skin after scratching. The skin may be irritated, swollen and possibly itchy. Symptoms usually appear within a few minutes of being rubbed or scratched; the Mayo Clinic reports that these symptoms can last 30 minutes to two hours. In rare cases, your inflammation may last several days and cause burning and pain.
The reasons your skin may become inflamed with bumps after scratching are not completely understood. If you suffer from dermatographia, the Mayo Clinic indicates that rubbing your clothes or bedsheets on your skin can trigger a reaction. Exposure to cold, heat, pressure, sunlight and emotion can also prompt the inflammation to appear.
To test for dermatographia, your doctor lightly scratches your skin with a tongue depressor and observes any inflammation marks. He may ask you to keep a detailed journal for two to four weeks to help identify possible causes of the dermatographia.
Your doctor may even test for allergens by performing an allergy skin test. The test usually involves pricking your skin and inserting pure allergens to see whether they cause a reaction.
Conditions such as dermatographia usually don't require any medical treatments, but if symptoms persist and become very uncomfortable, your doctor may recommend antihistamine medications. Antihistamines block histamine, which is a chemical that's released during an allergic reaction. You may need a combination of antihistamines to keep your inflammation under control.
Cool, wet compresses may help soothe your skin and prevent infections. The Mayo Clinic also recommends having a cool bath and even adding some colloidal oatmeal or baking soda to the bath water. Prevention is another way of treating your skin condition. Identify any allergens such as perfumes, soaps, clothing or detergents and avoid using them. Avoid scratching at your skin and keep your skin moisturized with perfume-free lotions.
Depending on what is causing your bumps to appear when you scratch, you may experience itching and discomfort. If it's caused by an allergic reaction, the allergic reaction can affect other areas of you body, including your throat and mouth. Swelling in those areas can lead to problems with breathing, unconsciousness and anaphylactic shock.