What is hand, foot and mouth disease? Hand, foot and mouth disease is an infectious disease caused by enteroviruses and is common in infants and young children, as well as in collective environments such as kindergartens and nurseries. The clinical manifestations of hand, foot and mouth disease are mainly symptoms such as herpes and ulcers on the hands, feet, mouth and other parts, which may be accompanied by fever, cough, diarrhea and other discomforts. Pictures of the early symptoms of hand, foot and mouth disease. The main symptoms of the early stages of hand, foot and mouth disease.