Currently, hand, foot and mouth disease is disseminated throughout the year in Fuyang, but the incidence gradually increases after the weather gradually warms up in February and March. If the rash on the hands, feet and mouth is not accompanied by fever, it is usually not a big problem. However, we should be alert to the fact that some children do not have a rash, but simply have a fever that does not go away, which makes diagnosis very difficult, even with laboratory tests. Some of these children can develop a serious illness very quickly and have a very high mortality rate, so what are the symptoms of these children that we should pay attention to? If the child has a high fever that does not go away, frequent vomiting, poor mental health, easy to startle, shaking, unstable standing and other symptoms, then parents and doctors should pay attention to it, even if it is not accompanied by a rash, we should consider the possibility of heavy encephalitis caused by enterovirus EV71, and promptly hospitalized for observation.