Hives, also called “urticaria”, is an allergic reaction that appears on the skin as a red, bumpy, and very itchy rash. The bumps may be referred to as “welts” or “wheals” and can arise anywhere on the body. Most people complain of hives because of the itch, which may also feel like burning or stinging.
Hives have a tendency to migrate around the body. An area of redness or itching may last just a few hours in one spot before fading away and developing somewhere else.
Hives are very common and 10-20% of people will experience hives at least once in their lives.
“Angioedema” is a form of hives that develops in the deeper tissues (subcutaneous) causing significant swelling. This occurs most commonly on the face. Rapidly developing angioedema is a medical emergency.
Hives are categorized as “acute” if they last less than 6 weeks, or “chronic” if they last more than 6 weeks.
Acute hives are usually caused by an allergic reaction or viral infection.
Acute hives go away after a few days or week, but may return again after exposure to the allergic trigger. Common triggers of hives includes foods (peanuts, chocolate, fish, tomatoes, eggs, milk), insect stings and medications (penicillin, sulfa drugs). The cause of acute hives can often be identified
Chronic hives are less likely to be due to an allergy. They may be caused by stress, autoimmune disorders, hormonal changes or some other systemic problem. Cholinergic urticaria is a type of hives that develops in response to being hot and sweaty. This can follow exposure to sunlight, exercise, hot baths, blushing or episodes of anger.
Unfortunately, most people with chronic hives never determine the trigger of their hives. “Idiopathic urticaria” is the name given to hives when the cause is unknown.
“Dermatographism” is a form of localized hives that develops in the area where the skin is scratched. It is quite common and affects nearly 5% of people.
When the cause of hives is known, the most important step is to eliminate the trigger.
When the cause is unknown (as for most people with chronic urticaria), medications can provide relieve from the symptoms.
Antihistamines provide the firsts step in medical treatment. Antihistamines are very effective when used properly. However, an antihistamin may not provide sufficient relief if the particular medication is not strong enough, the medication is not taken in sufficient doses, or the medication is not taken long enough to suppress symptoms.
Non-sedating anthistamines include:
Additional medications may be prescribed if a non-sedating antihistamine alone does not provide sufficient relief.
Sedating types of antihistamines may be suggested for use at night because they tend to cause sleepiness. These include diphenhydramine (Benadryl), hydroxyzine (Atarax) and doxepin.
Some of the medications used to control stomach acid can help to control hives. These medications, called H2-receptor antagonists, include cimetidine (Tagamet®), famotidine (Pepcid®), ranitidine (Zantac®), and nizatidine (Axid®),
Corticosteroids, such as prednisone, may also be prescribed to rapidly bring the hives under control. Because of the side effects associated with long-term use of corticosteroids, they are usually prescribed for short-term use.