What is Urticaria?
A term used to describe hives or pink swellings called wheals that may occur in groups on any part of the skin. New hives may develop as old ones are in the process of fading away. Hives are generally caused by histamine released from specialized mast cells that lie along the blood vessels in the skin, allowing small amounts of fluid to leak through the tissue producing a pink or red hive on the surface of the skin.
What causes Urticaria?
The most common causes of hives include foods, drugs and infections. Common foods that may cause hives include nuts, chocolate, fish / seafood, tomatoes, eggs, fresh berries and milk. Food additives may also contribute to the occurrence of hives. Almost all over-the-counter and prescription medication may cause hives, however more common ones include antibiotics, pain medications, sedatives, diuretics (water pills), antacids, vitamins, eye drops, laxatives, and vaginal douches. Many infections can cause hives as well, including viral upper respiratory tract infections, hepatitis B, bacterial and fungal infections.
Other more rare forms of urticaria include solar urticaria, cold urticaria, cholinergic urticaria, and dermatographism. Solar urticaria is caused by sunlight, showing up within minutes of sun exposure and then slowly fading away. Cold urticaria is caused by exposure to cold temperatures, and hives appear when the skin is warmed after exposure to the cold. Cholinergic urticaria presents with tiny bumps surrounded by a white or red halo which may come on with exercise, heat, or emotion. These bumps may itch intensely. Dermatographism is present when hives appear after stroking or scratching the skin in a linear fashion.
Not uncommonly, there is no apparent cause for hives. This condition is called chronic idiopathic urticaria. Most cases of chronic idiopathic urticaria are “autoimmune” in which the body’s immune system mistakenly attacks the mast cells causing them to release histamine and cause hives.
How is Urticaria Treated?
The best treatment is to find the cause and then eliminate it; however this may not be an easy task. In many cases the cause cannot be identified, and antihistamines may be used. Your dermatologist may prescribe steroid creams, oral medications, or a steroid injection for more severe urticaria. For chronic idiopathic urticaria, immunosuppressive medications may be needed if the disease cannot be controlled with antihistamines.