Hives, also called welts, are red and sometimes itchy bumps on the surface of your skin. An allergic reaction to a drug or food usually causes them. Allergic reactions cause your body to release chemicals that can make your skin swell up in hives. Other causes include infections and stress.
Hives are very common. They usually go away on their own, but if you have a serious case, you might need medication. In rare cases, allergic reactions can cause a dangerous swelling in your airways, making it hard to breathe. This is a medical emergency. Consult a dermatologist or allergist for more information.