A person with allergic urticaria has swelling of the skin, due to allergies.

Urticaria is the medical term for a type of allergic rash. Hives are the most common type of urticaria. Hives are itchy, pink to light red, raised blotches that are usually one-quarter to one-half inch in size, but may be quite large. Hives can occur on any part of the body. They usually develop quickly and spread over minutes to hours.