Hives — also known as urticaria (ur-tih-KAR-e-uh) — is a skin reaction that causes itchy welts, which can range in size from small spots to large blotches several inches in diameter. Hives can be triggered by exposure to certain foods, medications or other substances.
Angioedema is a related type of swelling that affects deeper layers in your skin, often around your face and lips. In most cases, hives and angioedema are harmless and don't leave any lasting marks, even without treatment.
The most common treatment for hives and angioedema is antihistamine medication. Serious angioedema can be life-threatening if swelling causes your throat or tongue to block your airway.
The welts associated with hives can be:
- Red or flesh-colored
- Intensely itchy
- Roughly oval or shaped like a worm
- Less than one inch to several inches across
Most hives go away within 24 hours. Chronic hives can last for months or years.
Angioedema is a reaction similar to hives that affects deeper layers of your skin. It most commonly appears around your eyes, cheeks or lips. Angioedema and hives can occur separately or at the same time.
Signs and symptoms of angioedema include
- Large, thick, firm welts
- Swelling and redness
- Pain or warmth in the affected areas
When to see a doctor
You can usually treat mild cases of hives or angioedema at home. See your doctor if your symptoms continue for more than a few days. Seek emergency care if you feel your throat is swelling or if you're having trouble breathing.
Hives and angioedema can be caused by:
- Foods. Many foods can trigger reactions in people with sensitivities. Shellfish, fish, peanuts, tree nuts, eggs and milk are frequent offenders.
- Medications. Almost any medication may cause hives or angioedema. Common culprits include penicillin, aspirin, ibuprofen (Advil, Motrin IB, others), naproxen (Aleve) and blood pressure medications.
- Common allergens. Other substances that can cause hives and angioedema include pollen, animal dander, latex and insect stings.
- Environmental factors. Examples include heat, cold, sunlight, water, pressure on the skin, emotional stress and exercise.
- Underlying medical conditions. Hives and angioedema also occasionally occur in response to blood transfusions, immune system disorders such as lupus, some types of cancer such as lymphoma, certain thyroid conditions, and infections with bacteria or viruses such as hepatitis, HIV, cytomegalovirus, and Epstein-Barr virus.
- Genetics. Hereditary angioedema is a rare inherited (genetic) form of the condition. It's related to low levels or abnormal functioning of certain blood proteins that play a role in regulating how your immune system functions.
Hives and angioedema are common. You may be at increased risk of hives and angioedema if you:
- Have had hives or angioedema before
- Have had other allergic reactions
- Have a disorder associated with hives and angioedema, such as lupus, lymphoma or thyroid disease
- Have a family history of hives, angioedema or hereditary angioedema
Severe angioedema can be life-threatening if swelling causes your throat or tongue to block your airway.
To lower your likelihood of experiencing hives or angioedema, take the following precautions:
- Avoid known triggers. These can include foods, medications and situations, such as temperature extremes that have triggered hives or angioedema in the past.
- Keep a diary. If you suspect food is causing the problem but aren't sure which food is the trigger, keep a food and symptom diary.