The redness of the face is due to the dilatation of the capillaries in the face, and its causes include physiological factors and pathological factors (including rosacea, systemic lupus erythematosus, systemic diseases, etc.). 1. Physiological factors: Under normal circumstances, if the face is exposed to sunlight due to weather, or in highland areas, or emotional excitement, etc., physiological facial capillary dilatation is likely to occur, and the phenomenon of facial redness occurs, which is a normal physiological factor and will not affect the health of the body. 2. Pathological factors (1) Rosacea: the etiology of this disease has not been fully clarified, may be related to seborrhea, follicular helminthic mite infection, heredity, local vasodilatation nerve dysregulation, etc., manifested as erythema, papules, pustules, nodules, nasal redness, etc., on the cheeks, nose, forehead and other parts of the body. (2) Systemic lupus erythematosus: the cause of this disease has not been completely clarified, may be related to immune system disorders, genetic factors, environmental factors, pathogenic microorganisms, androgens and other factors, manifested in the bridge of the nose and cheek cheeks in a butterfly distribution of erythema, but also in the palms of the fingers and palms, periungual, face and trunk and other parts of the erythema or flaky red spots and other symptoms. (3) Systemic diseases: If there is low fever for a long time, heart failure and other diseases, facial redness is easy to appear. It is suggested that if patients exclude physiological factors, they need to go to regular hospitals in time, under the guidance of the doctor for a clear diagnosis and reasonable treatment.