Rash in 2-year-old baby with high fever may be caused by the occurrence of Kawasaki disease, infectious mononucleosis or hand, foot and mouth disease. 1. Kawasaki disease: also known as mucocutaneous lymph node syndrome, can be manifested as fever, body temperature up to 39 ~ 40 ℃, which can last for a long time, the skin can appear polymorphic erythema and scarlet fever-like rash, in addition, there can also be bulbous conjunctiva congestion, hand and foot hard edema, palm and metatarsal erythema, oral mucosal diffuse congestion and strawberry tongue and other manifestations. 2. Infectious mononucleosis: acute infectious diseases caused by EBV, usually with fever 38 ~ 40 ℃, fever usually 1 ~ 2 weeks, in the course of the disease can have polymorphic rash. 3. Hand, foot and mouth disease: when the child is infected with enterovirus, caused by hand, foot and mouth disease, can be acute onset, the child may have fever appears, hands, feet, mouth and other parts of the scattered rash or herpes can be seen, more than 1 week after the cure. Rash when the baby high fever, to the hospital specialist in a timely manner, after a clear cause, follow the doctor’s advice on the cause, symptomatic treatment.