Hives

Urticaria; Wheals

Hives are raised, often itchy, red bumps (welts) on the surface of the skin. They can be an allergic reaction to food or medicine. They can also appear without cause.

Hives (urticaria) - close-up

Hives develop when histamine is released into the small blood vessels (capillaries). The capillaries dilate which causes a welt, and fluid oozes into the surrounding tissue, causing swelling. Histamine also causes intense itching.

Food allergies

The body's immune system normally reacts to the presence of toxins, bacteria or viruses by producing a chemical reaction to fight these invaders. However, sometimes the immune system reacts to ordinarily benign substances such as food or pollen, to which it has become sensitive. This overreaction can cause symptoms from the mild (hives) to the severe (anaphylactic shock) upon subsequent exposure to the substance. An actual food allergy, as opposed to simple intolerance due to the lack of digesting enzymes, is indicated by the production of antibodies to the food allergen, and by the release of histamines and other chemicals into the blood.

Hives (urticaria) on the chest

Hives (urticaria) are raised, red, itchy welts, seen here on the chest. The majority of urticaria develop as a result of allergic reactions. Occasionally they may be associated with autoimmune diseases, infections (parasitosis), drugs, malignancy, or other causes.

Hives (urticaria) on the trunk

This person has raised, red, itchy welts (urticaria) on the chest and abdomen. The majority of urticaria develop as a result of allergic reactions. Occasionally, they may be associated with autoimmune diseases, infections (parasitosis), drugs, malignancy, or other causes.

Hives (urticaria) on the chest

The hives (urticaria) on this person's chest have the typical slightly-raised red appearance and are accompanied by itching. Hives can be generalized over the entire body or may be localized.

Hives (urticaria) on the back and buttocks

These are hives (urticaria) with the typical slightly-raised red appearance, and are accompanied by itching. These are located on the buttocks. Hives can be generalized over the entire body or may be localized, and usually result from an allergic reaction.

Hives (urticaria) on the back

The hives (urticaria) on this person's back have the typical slightly-raised red appearance and are accompanied by itching. Hives can generalized over the entire body, or may be localized.

Hives

Hives are raised red welts of various size on the surface of the skin, often itchy, which come and go. Also called uticaria, hives is usually part of an allergic reaction to drugs or food. The term dermatitis describes an inflammatory response of the skin, caused by contact with allergens or irritants, exposure to sunlight, or by poor circulation, even stress. AVOID SCRATCHING. Scratching the rash may spread the inflammation, lead to infection and even leave scars.

Hives treatment

When there is an allergic reaction in the body, a chemical called histamine, from specialized cells in the body tissues is released. Histamine causes allergy symptoms such as sneezing, itching, watery eyes, and runny nose. Antihistamines may reduce inflammation, itching, and swelling by blocking the effects of histamine, reducing the allergy symptoms.

Hives are allergic welts on the skin. I'm Dr. Alan Greene and let's talk about hives, how they happen, and what to do about them when you do get them. Hives are usually triggered by some kind of exposure. The most common ones are to medicines and to foods. But they can be to all kinds of different things. Even cold weather will cause hives in some people. Most of the time we don't figure out what the trigger actually was. But it's worth trying to figure out if you can. Sometimes the hives can be a sign of an allergic reaction that's serious. If you have hives and also have any difficulty breathing or have wheezing, consider that something when you need urgent medical attention. Otherwise with hives, usually you can calm down the swelling and the itching with an antihistamine. Typical over-the-counter antihistamine can work well. It's even stronger if you couple it with one of the over-the-counter antacids. An H1 blocker and an H2 blocker together such as Benadryl, or diphenhydramine, and cimetidine. Taking those together is more powerful than either one alone. You can talk to your pharmacist about how to combine an H1 and H2 blocker safely. Usually with that kind of treatment, the itching will subside fairly quickly and the whole thing will last for just a few hours unless the exposure is ongoing. Sometimes though, hives will become chronic. If you have hives that are lasting for a week or more, you certainly want to be in touch with your doctor to discuss what to do with longer lasting hives.

Causes

Symptoms

Exams and Tests

Treatment

Outlook (Prognosis)

Possible Complications

When to Contact a Medical Professional

Prevention