The causes of facial redness are many, including physiological and pathological two types, such as emotional tension, strenuous exercise and other physiological factors, as well as contact dermatitis, rosacea and other pathological factors. 1. Physiological: when the patient’s emotional tension or anger, as well as just after strenuous activities, can lead to the phenomenon of capillary expansion of the face, resulting in facial redness, which is a relatively normal physiological phenomenon, generally soon return to normal; secondly, when the patient was exposed to ultraviolet radiation, due to temperature changes, can also cause facial redness, which is commonly known as plateau red. 2. Pathologic: (1) contact dermatitis: refers to the skin contact with certain exogenous substances, causing inflammatory reactions in the contact area or outside the skin. Both can cause local skin erythema, edema, papules and other phenomena, so the face can be red. (2) Rosacea: related to genetics, skin immunity and vasodilatation function abnormality, preferably in the middle of the face, is a chronic inflammatory skin disease with persistent erythema and capillary dilatation, so it can also lead to the symptoms of facial redness. The causes of facial redness are many, it is best to go to the hospital to improve the examination to clarify the diagnosis.