The face is always red and hot may be a normal physiological phenomenon, but also may be the facial dermatitis and dengue and other causes. 1. Normal physiological phenomenon: after strenuous exercise or when the surrounding environment is hot, due to the expansion of capillaries, which is prone to the phenomenon of redness and heat of the facial skin. 2. Facial dermatitis: the face is always red and hot may be caused by facial dermatitis. Facial dermatitis is usually caused by allergies or facial capillary dilatation caused by localized redness, swelling and fever. 3. Dengue: It is an acute non-purulent inflammatory skin disease caused by infection. As a result of small damage to the surface of the skin and the decline of the body’s immunity, it leads to bacterial infection, edema, flaky erythema and causes the symptom that the face is always red and hot. There are many causes of redness and fever of the face, and patients should go to the hospital in time to cooperate with doctors for active treatment when this symptom occurs.