Hives, or “wheals,” are pale red swellings of skin that occur in groups on any part of the skin. Urticaria is the medical term for hives. Each hive lasts a few hours before fading without a trace. New areas may develop as old areas fade. They can vary in size from as small as a pencil eraser to as large as a dinner plate and may join together to form larger swellings.
Hives are formed by blood plasma leaving out of small blood vessels in the skin. This is caused by the release of a chemical called histamine. Allergic reactions, chemicals in foods or medications can cause histamine release. Sometimes, it’s impossible to find out why hives are forming.
Hives are very common: 10-20 percent of the population will have at least one episode in their lifetime. Most episodes of hives disappear quickly in a few days to a few weeks. Occasionally, a person will continue to have hives for many years. There are several types of hives: chronic urticaria, lasting more than six weeks; physical urticarias, caused by sunlight, heat, cold, pressure, vibration or exercise; and dermatographic urticaria, caused by stroking or scratching the skin.
The most common foods that cause hives are nuts, chocolate, fish, tomatoes, eggs, fresh berries and milk. Fresh foods cause hives more often than cooked foods. Food additives and preservatives may also cause hives. Almost any prescription or over-the-counter medication can cause hives. Some of those drugs include antibiotics, pain medications, sedatives, tranquilizers and diuretics (fluid pills). Diet supplements, antacids, arthritis medication, vitamins, eye and eardrops, laxatives, vaginal douches or any other non-prescription item can be a potential cause of hives. If you have an attack of hives, it is important to tell your doctor about all of the preparations that you use to assist in finding the cause.
The best treatment for hives is to find and remove the cause. This is not an easy task and often not possible. Antihistamines are usually prescribed by your dermatologist to provide relief. No one antihistamine works best for everyone, so your dermatologist may need to try more than one or a different combination to find what works best for you.