One of the common triggers for chronic hives is heat. Experts have identified a more specific allergic reaction to heat, called cholinergic urticaria, or heat hives. People with this condition often break out in hives and become extremely itchy when they exercise, are out in hot weather or even take a hot shower.
Although the two may be often confused, heat hives are different than ‘prickly heat,’ or heat rash. Prickly heat is the result of your sweat glands becoming blocked and thus causes a rash with small red raised spots. These spots usually appear on parts of the body that are covered by clothes. Prickly heat can also cause stinging or itchiness.
Heat hives results in a itching and burning sensation caused by an allergic reaction to a rise in skin temperature. These usually disappear once the skin cools down, but it can sometimes result in hives appearing all over your body.
Symptoms of cholinergic urticaria
As your body begins to warm up, you may notice an uncomfortable feeling. This is usually an indication that your body is reacting to the heat, and that hives will soon develop. Once the hives appear you might notice:
You might also find that you are unable to sweat until your hives have appeared or you are exposed to intense heat or prolonged exercise.
Keeping your skin cool
Heat hives occur when your skin temperature rises. The most obvious reason for this is being out in the hot weather, however, taking a hot shower, sweating or even eating spicy food can all raise the temperature of your skin. To help keep your skin cool:
Keep ice packs, cool compresses and cooling sprays with you when going outdoors in the hot weather
Avoid alcoholic beverages or illicit drugs, as these can raise your body temperature
Avoid eating spicy foods
Take cool showers instead of lukewarm or hot ones
Cool your body immediately after being in a hot environment with cool water, or sitting in an air conditioned environment
Wear lightweight, cotton clothes during the warmer months
Wear layers in colder months so you can remove layers when entering a warm environment. This can help you avoid overheating
- Avoid spending time outside when it is hot outside
Other home remedies for hives include applying a mixture of vinegar and water to your skin with a cotton ball.
Antihistamines are also helpful in reducing allergic reactions. There are a number of over-the-counter antihistamines available. If you don’t find these helpful, talk with your doctor about a prescription antihistamine.
In addition to antihistamines, steroids and corticosteroids are sometimes prescribed for occasional flare ups of heat hives. Steroids can be used as an after-the-fact medication if the reaction is severe and doesn’t disappear when you cool your body temperature or as a way to suppress the immune system to avoid the hives. These medications are only available through a prescription from your doctor.
An approach to the patient with urticaria: Clinical and Experimental Immunology
Heat Hives: Hives.org
Urticaria, Cholinergic: National Organization for Rare Disorders