Children itch when they are hot, and the possible clinical causes are cholinergic urticaria, eczema, and milia. 1. Cholinergic urticaria: this is more common, its onset and sports, alcohol or passive fever and other factors related to the clinical manifestations of the body in the heat of the body in a number of places appeared small and very itchy wind. The itchy bumps may subside within minutes or hours. 2. Eczema: this condition refers to a chronic inflammatory itchy skin disease, which is mainly associated with autoimmune function abnormalities, environmental temperature changes are triggering factors, clinical manifestations for the affected areas of the skin appear polymorphic rash, such as erythema, papules, papules and so on. It can be accompanied by itching, oozing and other symptoms. 3. Corns: This condition refers to a superficial, inflammatory skin disease that is more common in summer or hot and humid environments, which is related to the blockage of sweat ducts in the sweltering state of the skin, the clinical manifestations of the affected areas of the skin appeared elevated blisters, papules or pimples, accompanied by tingling, itching and other symptoms. It is recommended that people with related conditions should go to the dermatology department of the hospital for examination to make a clear diagnosis, so as to carry out targeted treatment.