What Is Dermatographism?

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Dermatographism is a common, benign skin condition in which even a small amount of pressure, like scratching, causes the skin to swell along the line where it was applied.

Also known as dermatographic urticaria, or "skin writing," the condition is not an allergy, though it can resemble an allergy-like rash and cause itching within a matter of minutes.

This article describes the symptoms and causes of dermatographism. It also explains how the condition is diagnosed and treated.

Dermatographia allergy on skin
atsawin1002 / iStock / Getty Images

Dermatographism Symptoms

The symptoms of dermatographism can vary. In simple dermatographism, people notice swelling and/or redness (erythema) where the skin has been stroked. For example, if they were to write their name on their skin with a fingernail, it would be visible, with raised lettering that is likely sharp and clearly defined.

In symptomatic dermatographism, a more rare condition, people experience swelling and redness but also significant itching (pruritus).

Some people may contend with only minor and short-lasting hives (urticaria). Others may develop symptoms that are more profound and aggravating—in some cases lasting anywhere from several hours to several days.

Otherwise, dermatographism usually clears on its own without treatment within 15 to 30 minutes. It rarely leaves any lasting marks on the skin.

Image of arm with dermatographism

Reproduced with permission from ©DermNet NZ and © Dr Mashihul Hossain www.dermnetnz.org 2022

Causes

Dermatographism is among the most common forms of urticaria, affecting between 2% and 5% of the world's population. As common as the condition is, gaps remain in researchers' understanding of the condition.

The hives and red welts on the skin are thought to occur because of an inappropriate release of histamines as the skin is irritated.

In addition to scratching, dermatographic urticaria may be caused by tight or abrasive clothes, wristwatches, jewelry, or belts, or the ear stems of eyeglasses. Urticaria can also be caused by environmental and health triggers, some of which may co-exist with dermatographism. Examples include:

Diagnosis

Dermatographism is typically diagnosed by the appearance of the rash under mechanical stress. A healthcare provider may lightly rub the skin with a tongue depressor or pen to see if the characteristic welt develops. Lab tests and imaging studies are generally not required.

If the reactions are especially severe or prolonged, you may be referred to a specialized allergist or dermatologist who can use a tool called a dermographometer to measure skin sensitivity in response to a preset amount of pressure. The findings can help point to the appropriate treatment.

If the cause is in doubt, the provider may explore other possible causes for the symptoms, including:

  • Latex allergy
  • Systemic mastocytosis (the abnormal accumulation of mast cells on the skin or internal organs)
  • Urticaria pigmentosa (characterized by brownish welts with itching)

False Dermatographism

When the skin marks are white, yellow, or black, immunologists refer to these as "false dermatographism." These marks look like dermatographic urticaria but have different underlying mechanisms.

  • White dermatographism is the development of temporarily blanched skin where the skin has been scratched. Capillary vasoconstriction (which regulates the diameter of blood vessels in the arteries) is the probable cause.
  • Yellow dermatographism is characterized by yellowish welts thought to be caused by deposits of bile acid under the skin (these can occur with cholestasis, or when bile cannot travel to the liver).
  • Black dermatographism is a non-allergic phenomenon in which contact with metal causes a blackish welt (likely due to deposits of metallic particles under the outermost layer of skin).

Treatment

Dermatographism usually does not need to be treated unless it is causing severe or prolonged symptoms.

If needed, over-the-counter oral antihistamines, like Allegra (fexofenadine) or Zyrtec (cetirizine), may be recommended to treat an acute rash and itching.

Less commonly, a prescription drug called cromolyn sodium may be used to help stabilize mast cells and prevent them from releasing histamine into the skin.

Coping

Dermatographism rarely requires treatment, but can often be prevented by avoiding the things that can cause a rash.

  • Avoid skin irritants: Harsh soaps, scented lotions, alcohol-based cleansers, and perfumes can cause skin irritation, leading to scratching and the onset of a rash.
  • Bathe wisely: Hot baths and showers can strip away much-needed oils, resulting in itchy, dry skin. Take shorter baths and showers with cooler water. Pat rather than rub the skin dry. Immediately moisturize to keep skin soft and hydrated.
  • Wear soft, loose-fitting clothes: Avoid scratchy fabrics, heavy wools, and clothes that feel tight or abrasive.
  • Keep your fingernails short: Trimming and filing your nails can help reduce the risk of accidental scratches.
  • Drink lots of water: Your skin consists of nearly 65% water, and it needs regular infusions of this nutrient to stay healthy. Dehydration can lead to skin dryness and itchiness.
  • Protect yourself from the sun: Excessive sun exposure also causes dryness and itching. When out in the sun, use a minimum SPF 30 sunscreen and moisturize when you return home. Avoid the midday sun, and keep yourself well-covered with a hat, long sleeves, and sunglasses whenever in bright sunlight.

Moisturize Regularly

Good daily skin care can prevent the development of dermatographic hives. Keeping your skin soft and well-hydrated with an emollient moisturizer will make you less likely to experience dryness that can lead to itching and scratching.

Summary

When you break down the word "dermatographism," it means exactly what you think it would: "Writing on the skin." It is when pressure, scratching, itching, or stroking causes the skin to break out in welts or hives.

These physical signs appear about five minutes after the skin has been irritated and usually disappear about 30 minutes later. Dermatographism rarely requires treatment, but you can take proactive steps to avoid causing a rash.

A Word From Verywell

Dermatographism can be annoying, but it's usually not severe. However, if your symptoms are difficult to control, don't hesitate to see a dermatologist. New patients often are surprised to learn there usually is a simple explanation (and a simple remedy) for a skin problem or mystery they've been dealing with for years.

Frequently Asked Questions

  • Is dermatographism an allergy?

    No. It's a skin condition—and a common one at that. It is a sign that the skin is sensitive to touch or pressure. Usually, a rash caused by allergy will be itchier and last longer than a dermatographic rash.

  • Is dermatographism caused by stress?

    It's possible there is a link—especially between stress, inflammation, and dermatographism—but researchers haven't found tangible support for this theory.

  • Will dermatographism go away on its own?

    Dermatographic hives usually go away on their own within 30 minutes. In the meantime, try to avoid scratching the area if it is itchy. This can cause more hives to appear.

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. American Osteopathic College of Dermatology. Your daily do's of dermatology-Dermatographism.

  2. Happel CS, Saini S. Biomarkers to diagnose, assess and treat chronic spontaneous urticaria: Not there yetCurr Treat Options Allergy. 2017;4: 438–449. doi:10.1007/s40521-017-0147-z.

  3. Godse KV. Use of a ballpoint pen in the diagnosis of physical urticaria. Indian J Dermatol. 2011;56(1):119-20. doi:10.4103/0019-5154.77576.

  4. Nobles T, Muse ME, Schmieder GJ. Dermatographism. In: StatPearls [Internet]. StatPearls Publishing.

  5. U.S. Department of the Interior. The water in you: Water and the human body.

By Daniel More, MD
Daniel More, MD, is a board-certified allergist and clinical immunologist. He is an assistant clinical professor at the University of California, San Francisco School of Medicine and currently practices at Central Coast Allergy and Asthma in Salinas, California.