Angioedema (AN-gee-oh-eh-DEE-muh) is a sudden appearance of swollen patches (edema) on the skin or mucous membranes. It most often involves the face, lips, mouth, tongue, back of throat, or vocal cords. It may also occur in other places, such as the arms, legs, or genitals. A rash may also appear during the first 4 days of this illness.

There are different types of angioedema. Sometimes it's part of an allergic reaction (allergic angioedema). Other times it appears without any other signs of allergic reaction (isolated angioedema). In rare cases, it can run in families (hereditary angioedema).

Your symptoms will depend on what type of angioedema you have. Like allergic reactions, angioedema may include:

  • Rash, hives, redness, welts, blisters

  • Itching, burning, stinging, pain

  • Dry, flaky, cracking, or scaly skin

  • Swelling of the face, lips, tongue, or other parts of the body

More severe symptoms may include:

  • Trouble swallowing, or feeling like your throat is closing

  • Trouble breathing or wheezing

  • Hoarse voice or trouble speaking

  • Nausea, vomiting, diarrhea, or stomach cramps

  • Feeling faint or lightheaded, rapid heart rate, or low blood pressure

This condition can be triggered by exposure to certain things. Medical conditions involving the immune systems and certain infections may cause it. Sometimes the cause may be very clear. But it's often hard to find a cause. Hereditary angioedema can happen after exposure to stress, dental procedures, trauma, infection, or estrogen from contraception, hormone replacement therapy, or pregnancy. The most common causes of allergic angioedema include:

  • Foods such as shellfish, peanuts, milk products, gluten, and eggs. Also colorings, flavorings, and additives.

  • Insect bites or stings from bees, mosquitoes, fleas, or ticks

  • Medicines such as ACE inhibitors, penicillin medicines, sulfa medicines, aspirin, and ibuprofen

  • Latex, which may be in gloves, clothes, toys, balloons, and some kinds of tape. People who are allergic to latex may have problems with foods such as bananas, avocados, kiwi, papaya, or chestnuts.

  • Heat, cold, or sunlight

A common cause of angioedema is a reaction to a class of medicines called ACE inhibitors. These are used to treat high blood pressure. ACE inhibitors include lotensin, captopril, enalapril, and lisinopril. This condition can happen even after you've been taking the medicine for some time. Tell your healthcare provider if you have symptoms and are taking any of these medicines. Angioedema may happen again. It's important to watch for the earliest signs of this condition (see the list below). Contact your provider right away if swelling affects the face, mouth, or throat.

Home care

Rest quietly today. Don't do vigorous physical activity.

Medicines. Your healthcare provider may prescribe medicines for itching, swelling, or pain. Follow the provider’s instructions when taking these medicines.

  • Oral diphenhydramine is an antihistamine available without a prescription. Unless a prescription antihistamine was given, diphenhydramine may be used to reduce widespread itching. It may make you sleepy. So be careful using it when going to school, working, or driving. ( Note: Talk to your provider before using antihistamines if you have glaucoma, thyroid disease, heart disease, breathing problems, or high blood pressure. Or if you have trouble peeing due to an enlarged prostate.) Loratadine is an antihistamine that may cause less drowsiness.

  • Don't use diphenhydramine cream on your skin. Some people can have an allergic reaction to this.

  • Calamine lotion or oatmeal baths sometimes help with itching.

  • You may use acetaminophen or ibuprofen for pain, unless another pain medicine was prescribed. Ask your provider what medicines are safe for you. This is even more important if you have heart, kidney, or liver disease. Or if you're taking blood thinners, are at risk for gastrointestinal ulcers or bleeding, or have high blood pressure.

  • If you were told that your condition was caused by a medicine you are taking, you must stop taking it. Ask your provider for a different one. In the future, advise medical staff that you're allergic to this medicine.

  • If medicine was prescribed, such as steroids or antihistamines, make sure you understand what the medicine is and how to take it. 

General care

  • Make sure you don't scratch areas of the body that had a reaction. This will help prevent infection. 

  • Stay away from air pollution, tobacco, and wood smoke. Also stay away from cold temperatures. These things can make allergy symptoms worse.

  • Try to find out what caused your reaction. Make sure to stay away from the allergen. Future reactions may be worse. 

  • If you have a serious allergy, wear a medical alert bracelet that notes this allergy.

  • If the healthcare provider prescribed an epinephrine auto injector kit, make sure they teach you how and when to use it. Keep it with you at all times. 

  • Tell all care providers about your allergy. Ask them how to use any prescribed medicines.

  • Keep a record of allergies and symptoms, and when they occurred. This will help your provider treat you over time. 

Follow-up care

Follow up with your healthcare provider, or as advised. You may need to see an allergist. An allergist can help find the cause of an allergic reaction. They can also give advice on how to prevent future reactions.

Call 911

Call 911 right away if any of these occur:

  • Trouble breathing or swallowing, or wheezing

  • Hoarse voice or trouble speaking, or drooling

  • Chest pain or tightness

  • Confusion, lightheadedness, or dizziness

  • Extreme drowsiness or trouble awakening

  • Fainting or loss of consciousness

  • Rapid heart rate

  • Low blood pressure

  • Vomiting blood, or large amounts of blood in stool

  • Seizure

  • Nausea, vomiting, diarrhea, abdominal pain, or stomach cramps

When to get medical advice

Call your healthcare provider right away if any of these occur:

  • Symptoms don't go away

  • Symptoms come back

  • Symptoms get worse or new symptoms develop

  • Hives feel uncomfortable

  • Fever of 100.4°F (38°C), or as advised by your provider

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