Facial redness may be caused by physiological factors such as emotional excitement and temperature changes, or it may be related to diseases such as contact dermatitis and rosacea. 1. Physiological factors: In emotional excitement, such as nervousness or happiness, or temperature changes, such as excessive heat or cold, the capillaries of the face become congested, which can lead to facial heat and redness. 2. Contact dermatitis: caused by skin contact with exogenous substances that irritate the skin or trigger an allergic reaction. The manifestations are erythema, mild edema, or pinpoint-sized dense papules. The patient will have the symptom of facial redness. 3. Rosacea: The etiology is complex and may be related to genetic factors, neurovascular dysfunction, skin barrier function damage, immune inflammatory response. The main manifestations of rosacea are redness of the skin, dilated capillaries, papules and pustules, which are manifested as facial redness. There are many causes of facial redness, after excluding physiological factors, patients are advised to go to the hospital in time, after clarifying the cause of the disease, under the guidance of the doctor for symptomatic treatment.