What Causes Hives and Angioedema?
Hives and angioedema form when, in response to histamine, blood plasma leaks out of small blood vessels in the skin. Histamine is a chemical released from specialized cells along the skin’s blood vessels. Allergic reactions, chemicals in foods, insect stings, sunlight exposure, or medicines can all cause histamine release. Sometimes it’s impossible to find out exactly why hives have formed. There are several different types of hives, including: Acute urticaria: Hives lasting less than six weeks. The most common causes are foods, medicines, or infections. Insect bites and internal disease may also be responsible. The most common foods that cause hives are nuts, chocolate, fish, tomatoes, eggs, fresh berries, and milk. Fresh foods cause hives more often than cooked foods. Certain food additives and preservatives may also be to blame. Medicines that can cause hives and angioedema include aspirin and other nonsteroidal anti-inflammatorymedications such as ibuprofen, high blood pressure med
