Stinging and scratching all over the body when the weather is hot may be caused by cholinergic urticaria. 1. Cholinergic urticaria is a special type of urticaria, mostly seen in young patients. After consuming spicy and irritating foods, being in an environment with high temperature, strenuous exercise, or even taking a hot bath that causes excessive increase in skin temperature, the cholinergic nerves of the body will release acetylcholine due to excitement, which will act on the mast cells to promote the release of histamine and the onset of the disease. 2. Cholinergic urticaria patients can appear 1~3mm in diameter round papules of wind, self-conscious intense itching, tingling or burning sensation, sometimes only intense itching without skin lesions, can be subsided in 30~60 minutes. It is recommended that patients go to regular hospitals in a timely manner, to clarify the cause, under the guidance of professional doctors for treatment.