Acute urticaria usually lasts no longer than 6 weeks. Acute urticaria can be associated with medications, food, inhalants and infections, and is characterized by the development of doughnut-like skin lesions accompanied by intense itching. Acute urticaria has a more rapid onset and the rash usually disappears spontaneously within a few hours and lasts no longer than 24 hours, but new hives may appear repeatedly, resulting in the formation of lesions over and over again, but the total duration of the disease does not usually exceed 6 weeks. Urticaria that lasts longer than 6 weeks is also called chronic urticaria. Acute urticaria symptoms may be severe, chest tightness, breathlessness, laryngeal edema, dyspnea or blood pressure drop and other symptoms, and even life-threatening, it is recommended that patients go to the hospital in time for treatment.