High fever in babies is commonly due to the invasion of pathogens in the body, these pathogens are commonly viruses, bacteria, mycoplasma, chlamydia, rickettsia and so on. Pathogens in the baby’s body inflammatory reaction, and lead to fluctuations in the baby’s body temperature, and even have a tendency to high fever. After the baby has a high fever, red spots appear on the facial skin, commonly following an inflammatory reaction. After the baby’s body temperature drops and the fever slowly fades, the facial capillary congestion will slowly reduce, there will be part of the facial capillary permeability is still enhanced, not completely restored, closed, is a more than normal congestion, so there will be erythema on the face.