Pressure urticaria is a physical urticaria characterized by red, local swelling and often painful rash that arises at the site of sustained pressure. Pressure urticaria may occur immediately after few minutes of pressure stimulus or may occur after hours, generally 3-6 hours in case of delayed pressure urticaria. Unlike other urticarias, treatment of pressure urticaria is often unsatisfactory and may severely impair the quality of life of the individuals.
Risk Factors for Pressure Urticaria
Anything that results in pressure may stimulate pressure urticaria. These includes but not limited to:
- Sitting on a hard surface, standing or walking
- Works that needs to carry heavy tools by hands
- Hand clapping
- Carrying heavy objects or even a handbag
- Wearing tight-fitting clothes like belts, shoes, bra etc.
- Dental work
- Kissing and sexual activities
Symptoms of Pressure Urticaria
Pressure urticaria is usually associated with deep, red, swelling of the skin (wheals) that may last for 8-72 hours. The wheal may be seen within few minutes or most commonly 3-5 hours after pressure stimulus. The swelling may be often itchy, burning and painful that may persist for several days and sometimes blistering may be seen. Commonly affected sites are the hands, feet, legs, buttocks, trunk, and the face. The lesion may also be seen in genitals. Sometimes the wheals may be accompanied by systemic flu-like symptoms like fever, chills, headache and joint pain. It is estimated that up-to 60% of the individual with pressure urticaria also have chronic urticaria.
Diagnosis of Delayed Pressure Urticaria
Delayed pressure urticaria may be diagnosed clinically based on the appearance of wheal in the areas of the pressure stimulus. It can also be confirmed by pressure challenge testing. In pressure challenge testing, the tests are generally applied on shoulder, upper back, or posterior thigh and the result is read after around 6 hours.
Treatment of Pressure Urticaria
Treatment of pressure urticaria is usually unsatisfactory, and antihistamines are generally not effective. There is no known cure, the ideal initial treatment would be to avoid the cause. Several other therapies have been tried, but results are often disappointing. Although high dose of antihistamines may be helpful in some patients, results are still not satisfactory. Several other therapies have also been tried with conflicting results and include nonsteroidal anti-inflammatory drugs (NSAID), Colchine, dapsone, sulfasalazine and ciclosporin.
Oral steroids, although not recommended for long term use, are thought to be the most effective treatment for delayed pressure urticaria. Topical steroids under occlusion may also be useful in local lesion.
Beside treatment it is necessary to avoid the aggravating factors. Always remember:
- Avoid wearing tight fitting clothes
- Avoid sitting or standing on hard surface for long duration of time.
- Avoid long walk; take a rest in between if you are for a long walk.
- Avoid lifting heavy items or broaden the handles of heavy items.