What is foot and mouth disease? Hand, foot and mouth disease in children is a common infectious disease, mainly caused by enterovirus, and is more common in infants and young children under 3 years old. Hand, foot and mouth disease can be spread through airborne droplets or acquired through contact with contaminated objects. Early Symptoms of Hand, Foot and Mouth Disease Early symptoms of hand, foot and mouth disease include fever, cough, diarrhea, etc., which usually last for 2 to 3 days. After that, a rash begins to appear on the local skin and gradually spreads to the hands, feet, mouth and other parts of the body. Children develop oral ulcers or herpes, which appear as white spots in the mouth