Hives (Angioedema, Urticaria, Wheals)
Hives, an allergic skin disorder, are raised round pink or red lesions with flat tops. They are itchy and warm to the touch. More severe hives, called angioedema, tend to be larger and linked to one another; they also penetrate more deeply into the skin. In rare cases, hives can develop in the mouth and throat, obstructing breathing or heralding a life-threatening anaphylactic reaction. Most often, hives are caused by food allergies, with the most frequent culprits being chocolate, shellfish, nuts, eggs, strawberries and other fruits, as well as food preservatives, dyes, and other food additives. Some people develop hives after eating even a minute amount of the offending food, while others break out only when they overindulge in it.
Certain drugs, especially penicillin, can also cause hives, as can aspirin and numerous other medications.
There are people who develop hives in response to contact with cats or other animals, insect bites, extreme temperatures, or exposure to detergents or dry cleaning chemicals on clothes. In others, hives appear as part of a photosensitive reaction to sun exposure, especially if certain medications are being taken. The role of stress in hives has been much debated; some allergists say it can be a factor, but other experts dispute this claim.
Diagnostic Studies and Procedures
Hives are easily self-diagnosed on the basis of their appearance and feel. If you have recurrent hives but do not know what triggers them, skin tests performed by an allergist can help identify the offending substances. If allergies are not responsible for persistent hives, more extensive testing will be necessary to identify their cause.
Medical Treatments
Hives usually disappear on their own within one to seven days of their development. In the meantime, if the cause is not obvious and you are taking any medication, call your doctor to ask if you should discontinue it. To alleviate itching and discomfort, a physician may prescribe an antihistamine in prescription-strength, such as diphenhydramine (Benadryl), cyproheptadine (Periactin), or hydroxyzine (Atarax). In mild cases, a nonprescription antihistimine may be sufficient. (Caution is needed when taking these drugs because they produce drowsiness.) If hives are widespread and severe, a doctor may prescribe a corticosteroid drug such as prednisone.
If symptoms of an anaphylactic reaction develop, or if there is a "lump" in your throat or a choking sensation, get immediate help by calling an ambulance or having someone take you to the nearest emergency room. In such a situation, an injection of epinephrine (adrenaline) is life saving.
Alternative Therapies
Herbal Therapy. Herbalists recommend a tea made from Urtica dioica, the stinging nettle plant, as a natural alternative to antihistamine drugs. This herb is also available as capsules made from a freeze-dried extract.
Hydrotherapy. Bath additives can often help ease the itching and discomfort of hives. Try cornstarch, baking soda, or colloidal oatmeal. If you have hives that are induced by exposure to cold temperatures, you may be able to build up your tolerance by taking a cool shower once or twice a day.
Nutrition Therapy. Try to identify the foods that you believe trigger your hives and then eliminate them from your diet. Follow up by returning the suspected offenders, one at a lime. If hives reappear, then you know you have correctly identified an offending food that you should avoid in the future.
Self-Treatment
A topical treatment such as calamine lotion can ease the itching of hives, and an over-the-counter antihistamine can speed healing. If you suffer with chronic hives, your doctor may also recommend the following preventive measures: Avoid aspirin and other non-steroidal anti-inflammatory drugs, such as ibuprofen. These medications sometimes provoke hives and other allergic reactions involving the skin. Avoid these food additives: tartrazine, a common food and drug coloring; the food dye FD&C Yellow No. 5; benzoate food preservatives; and the preservatives BHA, BHT, and nitrates.
Other Causes of Hives
In unusual cases, hives may be the first sign of a viral infection, such as hepatitis, rubella, or mononucleosis, as well as serious illnesses, such as lymphoma, lupus, hyperthyroidism, or cutaneous vasculitis. In rare instances, chronic angioedema is caused by a hereditary enzyme deficiency.