The order of rash appearance is from top to bottom, first seen on the head and face, then the neck, chest, abdomen, 24 hours basically all out, the rash on the extremities is rare or no rash on the extremities. It is a common viral infection in children between the ages of 8 months and 2 weeks, and is characterized by a high clinical fever, often around 39°C. After 3-4 days of high fever, the fever subsides and the rash emerges. If antipyretic medication is used during the fever, the child’s mental state is good after the temperature drops, appetite is generally unaffected and is rarely accompanied by other infections of the respiratory tract, such as bronchitis or pneumonia, and the clinical course is relatively good, but attention must be paid to temperature control during the high fever.