Hives, or urticaria, are red, extremely itchy areas of swollen skin called wheals that can range in size from pin-size dots to large patches. These wheals may be circular or irregular in shape, but with distinct edges.
Hives usually present with a sudden onset of itching and swelling of the skin’s surface into red or skin-colored welts or blisters. The welts may change shape, develop a white or pale center, or suddenly disappear without cause in a matter of minutes or hours. They can last as long as a day or two, or recur on and off for months. A normal bout lasts less than six weeks. While hives can appear on any part of the skin, they tend to be worse in areas that are usually compressed by clothing or where the skin rubs together.
Hives are common: Up to 20 percent of people get hives at some point in their lives. They are especially common in people who have had other allergic reactions, such as hay fever.
What causes hives?
Hives are an allergic reaction that can be caused by a variety of environmental factors, such as something you’ve eaten, touched, or inhaled. Tension and emotional stress can also trigger hives.
Antibiotics are a common cause of hives. Penicillin and cephalosporins are classic triggers. These drugs can induce hives even if someone has taken the antibiotic many times before without any problem. Aspirin is another offender, as is the coating used on multivitamins and other pills. Reactions to food additives, specific foods, cosmetic ingredients, and animal dander may be involved. Some people develop hives after taking a hot shower, bath, or Jacuzzi, while others develop them after being out in the sun, or exposed to cold wind or water.
Viral infections may cause hives, as can other infections. Many people are surprised to find that they develop hives after an exercise session. While you may search for an exact cause for your hives, remember that in more than half of the cases, an exact cause is never discovered.
What if you do nothing?
Hives generally will go away on their own within several hours.
Home remedies for hives
- Try over-the-counter remedies. Antihistamines are the mainstay of hive relief. The best way to relieve the itching and swelling of hives is to take an oral antihistamine such as diphenhydramine(Benadryl) or chlorpheniramine maleate (Chlor-Trimeton). Remember, however, that most antihistamines will produce drowsiness, so follow package directions. Or, look for a second generation H1 antihistamine such as cetirizine (Zyrtec), Fexofenadine Hcl (Allegra), or loratadine (Claritin), which are less likely to cause drowsiness.
- Ice them. For temporary relief of itching and swelling of small hives, rub ice directly over the hives for several minutes. This will slow the release of itch-causing histamines. You can also try placing a cool cloth over the hives, or take a cool shower.
- Soak and soothe. Add colloidal oatmeal to a tepid bath and soak in the water for 15 minutes to temporarily soothe your skin. Cold compresses and calamine lotion can also help relieve the itching.
- Analyze your diet. Temporarily remove or permanently eliminate foods from your diet that regularly cause hives to develop. Some of the prime offenders often include shellfish, dairy products, nuts, pork, strawberries, chocolate, tomatoes, and oranges.
- Avoid aspirin, alcohol, and NSAIDs. These drugs may worsen hives.
How to prevent hives
- Find your allergen. This may be easier said than done, and unfortunately, many people never find the exact cause of their problem because there are multiple trigger factors. If you find that you have recurring bouts of hives, try to pay attention to whether they occur in the same place each time. Often when the hives are fixed in one location, there is a particular trigger and the hives occur in the same place each time you are exposed to that trigger.
- If you know what your allergen is, avoid it. If you are at risk for an allergic reaction, especially ones such as to bee stings or peanuts, you are a potential candidate for anaphylactic shock, a life-threatening situation that can lead to suffocation, loss of consciousness, and death. Avoid these allergens, and be sure to carry a special anaphylaxis emergency kit with you at all times.
When to call your doctor about hives
Contact your doctor immediately if you develop hives in your throat and breathing becomes difficult. Also call your doctor immediately if you develop hives after taking a medication for some other condition—especially if you also experience dizziness, wheezing, or breathlessness. The next dose may bring on a more dangerous swelling in the throat and could lead to anaphylactic shock.
If you develop hives after being stung by a bee or other biting insect, call your doctor, who can determine if you are allergic to stings and can recommend appropriate treatment. Also call your doctor if the hives become uncomfortable, if the hives are severe, if they are accompanied by swelling of the eyelids or lips, or if they do not respond to treatment after six weeks.
What your doctor will do
Your doctor will analyze your diet, medication, and review any recent sickness. For chronic hives, laboratory studies may be performed. Your doctor may also have you try various antihistamines over a series of weeks to see if any of the medications help resolve symptoms. Your doctor may also prescribe corticosteroid drugs to treat severe hives.
Also see Dry Skin: Causes and Treatments.