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. Most cases of hives, ( about 95%), will be diagnosed as acute as they last less than 6 weeks and then resolve spontaneously. The remainder will be diagnosed as chronic urticaria and they can last for years.
- Hives can appear on any area of the body; they may change shape, move around, disappear and reappear over short periods of time.
- The bumps – red or skin-colored “wheals” with clear edges – usually appear suddenly and go away just as quickly. They typically do not stay in one place for greater than 24 hours.
- Pressing the center of a red hive makes it turn white – a process called “blanching.”
Common Triggers of Hives
- Some food (especially peanuts, eggs, nuts and shellfish)
- Medications, such as antibiotics (especially penicillin and sulfa), aspirin and ibuprofen
- Insect stings or bites
- Physical stimuli, such as pressure, cold, heat, exercise or sun exposure
- Blood transfusions
- Bacterial infections, including urinary tract infections and strep throat
- Viral infections, including the common cold, infectious mononucleosis and hepatitis
- Pet dander
- Some plants, such as poison oak and poison ivy
In some cases, the trigger is obvious – a person eats peanuts or shrimp, and then breaks out within a short time. Other cases require detective work by both the patient and the physician because there are numerous possible causes. In many cases, the cause cannot be identified.
- A single episode of hives (acute hives) does not usually call for extensive testing. Often a detailed history is all that is needed,
- Chronic hives often necessitates further evaluation including asking about your and your family’s medical history, substances to which you are exposed at home and at work, exposure to pets or other animals and any medications you’ve taken recently.
- Testing for hives can include skin tests, blood tests and urine tests to identify the cause of your hives.
- This can include testing for food if indicated.
- A skin biopsy may also be needed to confirm the diagnosis of hives and rule out other causes such as vasculitis.
- In spite of a thorough evaluation, a cause of chronic hives is often not found.
Management and Treatment of Hives
- If the cause of hives can be identified, the best treatment is to avoid the trigger or eliminate it.
- Foods: Don’t eat foods that have been identified to cause your symptoms.
- Avoid rubbing or scratching.
- Avoid harsh soaps.
- Constant pressure: Avoid tight clothing as pressure exacerbated hives can be relieved by wearing loose-fitting clothes.
- Temperature: If you develop hives when exposed to cold, do not swim alone in cold water and always carry an epinephrine auto-injector. Avoid exposure to cold air and use a scarf around your nose and mouth in cold weather. If you must be out in the cold, wear warm clothing.
- Sun exposure: Wear protective clothing; apply sunblock.
- Medications: Notify your physician or pharmacist immediately if you suspect that a specific medication is causing your hives.
- Antihistamines – available either over the counter or by prescription – are a frequently recommended treatment for hives. Low-sedating or nonsedating antihistamines are preferred.
- Severe episodes of urticaria may require temporary treatment with systemic steroids (either via pill or shot).
- If your reaction involves swelling of your tongue or lips, or you have trouble breathing, you will likely be prescribed an epinephrine (adrenaline) auto-injector for you to keep on hand at all times.