Most of the itchy skin rashes after sweating are caused by the recurrence of cholinergic urticaria and atopic dermatitis. 1. Cholinergic urticaria: a small windy skin disease caused by the release of acetylcholine from the peripheral nerves. It is mainly due to the patient after strenuous exercise, the temperature of the deep part of the torso rises, prompting acetylcholine to act on mast cells, caused by the sensitization reaction. The body can appear in the wind, accompanied by itching, skin flushing and other phenomena. 2. Atopic dermatitis: a chronic inflammatory skin disease related to genetic allergic qualities, manifested by itching, polymorphic skin lesions, such as dense corn-grain-sized papules, papules or blisters, with a red base and a tendency to ooze. Patients are prone to atopic dermatitis flare-ups after sweating. It is recommended that when the skin itches and rashes appear after sweating, go to a regular hospital and be treated under the guidance of a dermatologist.