Urticaria, also known as hives, is an outbreak of pale red bumps or welts on the skin that appear suddenly. The swelling that often comes with hives is called angioedema. Allergic reactions, chemicals ...

Autoimmune hives (urticaria) are a type of rash caused by an overactive immune system that attacks healthy skin. It may be associated with an autoimmune condition, such as autoimmune thyroid disease.