Types
Acute Urticaria - When the rash from the hives lasts less than six weeks. In this type of urticaria the offending allergen is identified. The allergy-causing agent is one of the many triggering factors that are usually associated with hives.
Chronic Urticaria - When the rashes persists for more than six weeks the condition is chronic. In 80% of chronic urticaria the causative allergen is unknown (idiopathic urticaria). Here the hives may be caused by an autoimmune reaction.
