- chronic idiopathic urticaria - idiopathic urticaria treatment - idiopathic chronic urticariabr br Urticaria Treatmentbr br The best treatment for urticaria is to identify and avoid the cause and any aggravating factor.br br Doctors prescribe anti-histamines for immediate relief of symptoms.br br Antihistamines, when taken orally, take about an hour or so to relieve a rash. br br They work best if taken on a regular basic to prevent the eruption of urticaria. br To avoid side-effects like drowsiness, heaviness, non-sedative antihistamines are often taken side by side.