The redness of the baby’s face on one side and not on the other may be caused by pressure on one side of the face while sleeping, or it may be related to vasodilation, UV exposure or skin allergies. Parents should pay attention to observe whether the baby has other uncomfortable symptoms, and take the baby to the doctor for examination to clarify the cause of symptomatic treatment. Common causes 1, sleeping position: infants sleep in a side-lying position, when one side of the face is pressed, the blood flow is not smooth, which will lead to a red side of the face while not red phenomenon; 2, vasodilatation: the baby’s head and facial skin is very thin, rich in blood vessels, a large amount of blood flow, vascular expansion thickened, red, if there is a side of frostbite resulting in vasodilatation, there will be localized heat in the face, appearing red side Not red phenomenon; 3, ultraviolet radiation: baby’s skin is delicate and sensitive, easily sunburned by ultraviolet radiation, resulting in the symptoms of a red face; 4, skin allergies: baby belongs to the allergic body, one side of the face when exposed to pollen, dust mites and other allergens, easy to appear red face. Treatment 1, due to sleeping position or vasodilatation of the face red phenomenon generally do not need to be treated, after a period of time the baby’s face will naturally return to normal; 2, if the sunburn caused by red face, parents can use non-hormonal creams, such as butyl hydroxy acid cream or butyl flufenamic acid ointment under the guidance of a doctor to apply the sunburn site, you can also use sodium hyaluronate repair film to improve the damaged skin barrier function; 3 If the baby’s skin is red on one side due to cold, it is necessary to add warm tools such as scarves in time and move the baby to a warm room; 4. When the baby’s skin is red on the face due to allergies, parents can improve the allergy symptoms by using topical anti-allergy medications such as Benadryl on the affected area as directed by the doctor. Note that babies’ skin is too delicate and is easily affected by various environments and is in abnormal, so attention should be paid to protection, such as wearing a mask when going out and not using rough pillowcases.