Rash or herpes can also appear on the buttocks. Hand, foot and mouth disease is caused by enterovirus infection, the infected viruses are different, the clinical symptoms and manifestations are also different, among which the severe disease occurring with enterovirus 71 also called EV71 infection is more. Hand, foot and mouth disease is an epidemic every year, most of them are mild, the child has a fever, but most of them are low fever, does not last long, hands, feet, buttocks will have herpes, some oral herpes, but most of the children will be able to eat, mild cases are often in the 5-7 days of spontaneous healing. If the baby has repeated fever, clinical lethargy, body temperature above 38 ℃, manifested by dysphoria, vomiting, limb shaking, the emergence of these conditions may be the seriousness of hand, foot and mouth disease, to pay attention to and go to the hospital in a timely manner.