Hand, foot, and mouth disease (HFMD) is a common infectious disease in children caused by a variety of human enteroviruses. It was first reported in Canada in 1957, and in China it was first seen in Shanghai in 1981 and has been reported in subsequent cities. In May 2008, China designated it as a category C infectious disease for statutory reporting and management. HFMD occurs mostly in children under 5 years of age. Clinical manifestations are acute onset, fever, scattered herpes on the oral mucosa, maculopapular rash and herpes on the hands, feet, elbows, knees and buttocks, which may be surrounded by an inflammatory redness and less fluid in the herpes, and may be accompanied by cough, runny nose and loss of appetite. The disease mostly heals within a week and the prognosis is good. In very few cases (especially those younger than 3 years old), the disease progresses rapidly, with meningitis, encephalitis (brainstem encephalitis is the most dangerous), encephalomyelitis, pulmonary edema and circulatory disorders appearing in about 1 to 5 days after the onset of the disease, and in very few cases the disease is critical and can lead to death. Why children are susceptible to HFMD? People are generally susceptible to enterovirus, and different age groups can be infected with the disease, but mainly children aged 5 years and below, especially infants and children aged 3 years and below have the highest incidence rate, accounting for 85% to 95% of the incidence, mainly due to the low resistance of children in this age group, the antibodies given by the mother have disappeared, while their own cellular and humoral immune mechanisms have not yet been developed. The main reason for this is that children in this age group have a low level of resistance, the antibodies given by the mother have disappeared and their own cellular and humoral immune mechanisms are not yet developed. Patients, latent infections and asymptomatic carriers of the virus are the main sources of infection. The virus can be detected in the pharynx and feces of infected patients several days before the onset of the disease, and is usually most infectious within 1 week of onset. In the acute phase, patients have fecal detoxification for 4 to 8 weeks and pharyngeal detoxification for 1 to 2 weeks. Enterovirus can be transmitted via the gastrointestinal tract (fecal-oral route), as well as via the respiratory tract (droplets, coughing, sneezing, etc.), or by contact with the patient’s oral and nasal secretions, skin or mucosal herpes fluid, and contaminated objects. Specific immunity can be obtained after both overt and covert infections, and the neutralizing antibodies produced can stay in the body for a long time, producing strong immunity to the same serotype of virus, but there is little cross-immunity between different serotypes, so that more than one case of HFMD can occur with different serotypes of infection. How to early detection of children with severe HFMD With the following characteristics, especially patients under 3 years of age, the disease within 1 to 5 days, cases that may develop into severe disease in a short period of time, should be promptly seen in a regular hospital, closely observe changes in the condition, conduct the necessary auxiliary examinations, and perform targeted rescue and treatment to reduce the incidence of death. 1, persistent hyperthermia body temperature (axillary temperature) > 39 ℃ for more than 3 days, the conventional antipyretic effect is not good; 2, neurological performance appear mental depression or restlessness, vomiting, frequent jumping, shaking limbs, weakness, unstable standing or sitting; 3, respiratory abnormalities increased respiration, respiratory rhythm changes, need to be alert to pulmonary edema; 4, circulatory dysfunction increased heart rate, cold sweat, cold extremities, skin pattern 5. elevated peripheral blood leukocyte count more than 15×109/liter; 6. elevated blood glucose stress hyperglycemia, blood glucose >8.3 mmol/liter. How to treat and prevent HFMD Hand, foot and mouth disease is a self-limiting disease, ordinary cases are usually controlled within a week or so, with symptomatic treatment, home isolation, avoid cross-infection, proper rest, light diet, good oral and skin care. Serious cases need to be hospitalized and actively treated by professional medical staff. Good hygiene habits, regular work and rest and EV71 vaccination can help prevent HFMD.