When to Seek Medical Care

Contact your health care provider if you have hives or angioedema. After hearing your symptoms, he or she may want to see you for an office visit.

If you are having any of these symptoms along with hives or angioedema, you may be having an anaphylactic reaction. Go immediately to a hospital emergency department.

• Difficulty with breathing or swallowing Wheezing Abdominal pain, vomiting, or diarrhea General weakness Feeling dizzy, light-headed, or faint

Other reasons to go to the emergency department:

• Your hives or swelling do not improve after 2-3 days. You continue getting new hives after 2 days. Your symptoms do not get better with the treatment recommended by your health care provider.

Do not drive yourself; if no one is available to take you right away, call 911 for emergency transport. While waiting for the ambulance to arrive, begin self-treatment.

Self-Care at Home

• Stop any food or medicine 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 your health care provider, until symptoms subside. These can be effective for mild episodes. CAUTION: Antihistamines may make you 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 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 1-2 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, 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.

Prevention

Avoid exposure to any food, medicine, or physical agent that has been identified to cause your hives or angioedema.

Reducing emotional and physical stress may help. In rare cases, you may need to take antihistamines or other medicines for an extended time to prevent further hives or swelling.