Hives and angioedema
Hives, also often called uticaria, and angioedema are similar conditions that affect the skin. Sometimes caused by allergic reactions, these welts can last for several hours or even several days. Though the itching can be bothersome, they are generally not a serious condition.
Definition & Facts
Hives and angioedema are related conditions that show their effect on the skin. Hives are itchy welts on the skin that can range in size from small dots to several inches. They can be so large that several join together and are called plaques. They appear suddenly and can last for several hours to several days.
Angioedema are similar, but they affect the deeper levels of the skin, and thus, the swelling appears to be under the skin rather than on it. Angioedema is usually seen near the eyes, lips and cheeks, but it occasionally shows up on the genitals, hands, and feet.
Symptoms & Complaints
Hives are usually accompanied by intense itching, which only makes the situation worse. The welts are usually oval in shape, and they can be especially elongated to look like a squiggle. Hives usually go away, or at least lessen in intensity, within 24 hours, but chronic hives can last much longer, even several years.
Angioedema can occur separately from, or together with, hives. Because it affects the deeper layers of your skin, it appears as long, thick welts under the skin’s surface. It is most commonly seen around the eyes and lips. Angioedema most often presents as swollen, red areas on the face. Usually, these swollen areas are warm to the touch and accompanied by pain or tenderness to the touch.
Hives and angioedema are caused when a chemical, histamine, is released from specialized cells in the body. This histamine forces the release of blood plasma from the small vessels near the skin’s surface, causing the welts to appear. Histamine is a chemical in the body that is usually released in response to an allergen. Thus, allergens are often the cause of hives and angioedema.
Many people are sensitive to chemicals in the foods that they eat; that is, they have food allergies. Common foods that cause hives and angioedema are: nuts, chocolate, fish, tomatoes, eggs, fresh berries, soy, wheat, and milk. Some people can tolerate some of these foods if they are cooked first.
In addition, medicines such as penicillin, aspirin, nonsteroidal anti-inflammatory drugs, and blood pressure medicines; environmental allergens such as bug bites, pollen, latex, or pet dander; or infections can also cause hives or angioedema to appear. Moreover, some people get hives due to direct exposure to various irritants such as heat, cold, direct sunlight, vibration, pressure, and sweating. These hives usually appear with the exposure, and they go away soon after the problem is removed.
An underlying medical condition such as lupus, some types of cancer, and certain thyroid conditions, to name only a few, can also cause hives or angioedema. Two other causes of hives and angioedema are repeated scratching of the skin and heredity.
Diagnosis & Tests
Diagnosis of hives and angioedema will likely start with a complete medical history. Next, the doctor will ask many questions about any new foods, medications, or environmental irritants the patient may have ingested or been exposed to recently. This information may help the doctor to determine the cause of the hives or angioedema.
In addition, the doctor will likely examine any welts the patient may still have on his or her skin. Once the doctor has all of this information, he or she will attempt to narrow down the cause of the problem. Since there is no specific test for hives or angioedema, he or she will have to instead try to find the cause.
If the doctor suspects that allergies are the cause of the hives or angioedema, he or she may order allergy skin testing. The individual will have to visit an allergist, a doctor who specializes in allergies for this type of testing. These tests can help determine what agents he or she may be allergic to so he or she can avoid them in the future.
If the doctor suspects heredity may be the cause, he or she may order blood tests to check certain levels of blood proteins. Blood tests may also be performed if the doctor wants to check for other underlying medical conditions to see if they may be the cause of the hives or angioedema.
Treatment & Therapy
Many cases of hives require no treatment and, in fact, go away before a doctor's visit even occurs. If these cases of hives are frequent, a doctor may still be able to help the patient find the cause of the hives or angioedema so that future attacks can be prevented.
For cases of hives or angioedema that are extremely itchy or uncomfortable, an antihistamine is often prescribed. This can be taken to relieve the symptoms of allergic reactions. It may be taken only to relieve symptoms or on a consistent basis to help prevent their recurrence.
If the antihistamines do not provide enough relief or if hives are very severe, an oral corticosteroid may be prescribed to reduce swelling, redness, and itching. In cases where the hives are chronic, medications may be prescribed to control an overactive immune system. Furthermore, if it is determined that the patient has hereditary angioedema, the doctor may prescribe a protein controller so that the proteins in the blood stay at a consistently normal level.
In the most severe cases when angioedema restricts the airway, an injection of epinephrine may be necessary. This can be given at the emergency room or, if it becomes persistent, the patient can carry a portable supply or EpiPen® to self-inject.
Prevention & Prophylaxis
Cool, wet compresses or a comfortably cool bath can also help relieve the symptoms if they should occur. Finally, if an individual should break out, he or she should wear loose, cotton clothing that will not rub nor further irritate the skin.