Running skin itching may be sweat stimulation, blood circulation acceleration and other physiological factors, or consider cholinergic urticaria, contact dermatitis. 1. Physiological factors: strenuous exercise will lead to an increase in local sweat, sweat stimulation of the local skin, or may be the movement of blood flow is too fast, will increase the heat dissipation, such cases will appear running skin itchy situation. 2. Cholinergic urticaria: Cholinergic urticaria may be caused by strenuous exercise, hot baths, improper diet, emotional tension and other factors. Patients will experience self-conscious intense itching, tingling sensation, burning sensation, etc., which is manifested as itchy running skin. 3. Contact dermatitis: contact dermatitis may be caused by sweat, clothing, antiperspirant, soap and other material stimulation. Patients will have localized itching, burning, swelling and pain, manifested as itchy running skin. There are many causes of itchy running skin (such as prickly heat, eczema), which should be ruled out physiological factors, and then go to the hospital to find out the cause of the disease.