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Hives, also known as urticaria, affects about 20 percent of people at some time during their lives. It can be triggered by many substances or situations and usually starts as an itchy patch of skin that turns into swollen red welts. The itching may be mild to severe. Scratching, alcoholic beverages, exercise and emotional stress may worsen the itching.
- Hives (medically known as urticaria) are red, itchy, raised welts on the skin that appear in varying shapes and sizes; each one characteristically lasts no longer than six to 12 hours.
- Hives are very common, and most often their cause is elusive.
- Hives can change size rapidly and move around, disappearing in one place and reappearing in other places, often in a matter of hours.
- Ordinary hives flare up suddenly.
- Occasionally hives are produced by direct physical stimulation by environmental forces like heat, cold, and sunlight.
- Treatment of hives is directed at symptom relief until the condition goes away on its own.
- Antihistamines are the most common treatment for hives.
- Hives typically are not associated with long-term or serious
Types of Hives
A. Acute urticaria: Hives lasting less than six weeks. The most common causes are certain foods, medications, or infections. Insect bites and internal disease may also be responsible.
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. Certain food additives and preservatives may also be to blame.
Drugs that can cause hives and angioedema include aspirin and other nonsteroidal anti-inflammatory medications such as ibuprofen, high blood pressure drugs (ACE inhibitors), or painkillers such as codeine.
B. Chronic urticaria and angioedema: Hives lasting more than six weeks. The cause of this type of hives is usually more difficult to identify than those causing acute urticaria. For most people with chronic urticaria, the cause is impossible to determine. In some cases, though, the cause may be thyroid disease, hepatitis, infection, or cancer.
C. Physical urticaria: Hives caused by direct physical stimulation of the skin for example, cold, heat, sun exposure, vibration, pressure, sweating, and exercise. The hives usually occur right where the skin was stimulated and rarely appear elsewhere. Most of the hives appear within one hour after exposure.
D. Dermatographism: This is a common form of physical urticaria where hives form after firmly stroking or scratching the skin. These hives can also occur along with other forms of urticaria.
What Causes Hives?
Allergic hives and angioedema form when, in response to histamine, blood plasma leaks out of small blood vessels in the skin. Histamine is a chemical released from specialized cells along the skin’s blood vessels.
Allergic reactions, chemicals in certain foods, insect stings, sunlight exposure, or medications can all cause histamine release. It’s often impossible to find out exactly why hives have formed.
The most common signs (what you see) of hives are:
- Slightly raised, pink or red swellings .
- Welts that occur alone or in a group, or connect over a large area.
- Skin swelling that subsides or goes away within 24 hours at 1 spot but may appear at another spot
As for symptoms (what you feel), hives usually itch. They sometimes sting or hurt.
Some people always get hives in the same spot or spots on their body. These people often have a trigger (what causes the hives). Every time they are exposed to that trigger, they get hives.
How Are Hives Treated?
The best treatment for hives and angiodema is to identify and remove the trigger, but this is not an easy task. Antihistamines are usually prescribed by your doctor to provide relief from symptoms. Antihistamines work best if taken on a regular schedule to prevent hives from forming in the first place.
Chronic hives may be treated with antihistamines or a combination of medications. When antihistamines don’t provide relief, oral corticosteroids may be prescribed. A biologic drug, omalizumab (Xolair), is also approved to treat chronic hives in those at least 12 years of age.
For severe hive or angioedema outbreaks, an injection of epinephrine (adrenaline) or a cortisone medication may be needed.
What Are Home Remedies for Hives
- Stop any food, medicine, cosmetic, or other substance identified as the cause of the hives or angioedema.
- In very mild cases, no treatment at all may be required.
- If symptoms are making you uncomfortable, take a nonprescription antihistamine, such as diphenhydramine (Benadryl), by mouth, per the package instructions or as directed by a health-care professional, until symptoms subside. These can be effective for mild episodes. Sedating antihistamines such as diphenhydramine may make one too drowsy to drive or operate machinery safely.
- Cool compresses or baths may help with the discomfort.
- Avoid hot baths or showers.
- Avoid direct sunlight.
- Wear light, loose-fitting clothing.
- Avoid strenuous activity or anything that might cause sweating.
- Try to relax and reduce stress.
Severe reactions: Do not attempt to treat severe reactions with home remedies or to wait it out at home. Go immediately to the nearest emergency department or call an ambulance. Here are some things you can do while waiting for the ambulance:
- Try to stay calm.
- If you can identify the cause of the reaction, prevent further exposure.
- Take an antihistamine, such as one or two tablets or capsules of diphenhydramine (Benadryl), if you can swallow without difficulty. The liquid form of diphenhydramine (Benadryl) can also be used at 2-4 teaspoons (10-20 mL) per dose.
- If you are wheezing or having difficulty breathing, use an inhaled bronchodilator, such as albuterol (Proventil), if one is available. These inhaled medications dilate the airway.
- If you are feeling light-headed or faint, lie down and raise your legs higher than your head to help blood flow to your brain.
- If you have been given an epinephrine kit such as an EpiPen, inject yourself as you have been instructed. The kit provides a premeasured dose of epinephrine, a prescription drug that rapidly reverses the most serious symptoms (see Follow-up).
- Bystanders should administer CPR to a person who becomes unconscious and stops breathing or does not have a pulse.
- If at all possible, you or your companion should be prepared to tell medical personnel what medications you take and your allergy history.