Cholinergic urticaria is not caused by low immunity. Cholinergic urticaria is mainly related to the increase of body temperature in the local center of the skin. Common triggers such as hot baths, exercise, hot weather, drinking alcohol, eating spicy food, etc., prompt the cholinergic nerve impulses, thus releasing acetylcholine, which acts on the mast cells and develops the disease, and therefore is not caused by low immunity. Cholinergic urticaria manifests itself as itchy or even stinging skin masses, which usually subside naturally within minutes or hours, but can recur for months or even years, and in severe cases, symptoms such as nausea, abdominal pain, headache, and even fainting may occur, so it is recommended to go to the dermatology department of a regular hospital in a timely manner for treatment.