The rash of urticaria is subcutaneous congestion, which can be aggravated by heat or heat stimulation followed by emotional stress, leading to an aggravation of the rash. There is no need to panic after the occurrence of the rash, it can be restored to normal by returning to a cool room and leaving it for about half an hour. If the rash does not recover or if the itching is severe, you can wipe it with a warm, cool towel and temporarily take oral anti-allergy medication, such as cetirizine tablets. Patients with urticaria should try to avoid heat stimulation during the acute phase, avoid hot baths, rinse with warm, cool water, and try to avoid heat stimulation.