HFMD is an acute febrile, rash-like illness caused by enterovirus infection. Children under 5 years of age, especially those under 3 years of age, are susceptible to the HFMD virus and are prone to HFMD. Older children are also more susceptible to HFMD than adults, who have better resistance. HFMD infection passes as a latent infection and severe HFMD is quite rare in adults. However, children under 5 years of age with severe HFMD need special attention. Because the child’s immune function is poor, the development of organ function is relatively immature, once attacked by enterovirus infection, hand, foot and mouth disease is relatively heavy, especially enterovirus 71 infection of children, easy to suffer from severe hand, foot and mouth disease.