Urticaria with erythema is caused by the occurrence of angioedema, the reduction of edema after the change of the wind mass into erythema, and the purple may be caused by the aggravation of the symptoms. 1. Erythema: the most important manifestations of urticaria are the spontaneous wind-bubble and angioedema. A wheal is a temporary, raised skin lesion. Usually varying in size, red or pale, can be fused into a piece, or isolated distribution, the appearance of the orange peel, when the edema reduces and flattens, the wind ball will change to erythema. 2. Purple: may make the symptoms aggravated so that the erythema becomes darker and looks purple, such as infection, allergy, aspirin, penicillin and other drugs, ultraviolet stimulation during sun exposure, etc., can make the symptoms aggravated. Hives can be accompanied by itching and other symptoms, it is recommended to seek medical treatment.