HFMD is commonly caused by Coxsakie A16 virus and occasionally by other types of viruses such as Coxsakie A and B virus, Enterovirus 71, other enteroviruses, and the herpes virus. The viruses are acquired by oral or respiratory route, and they are common in the late summer and early fall in temperate climates. The incubation period for HFMD from time of exposure to manifestation of the illness is 3-7 days. Mild symptoms of low fever, malaise, sore throat, runny nose, diarrhea, and abdominal pain may preceed the oral lesions. The time frame when such symptoms occur is called the prodromal phase.
Oral lesions appear before the lesions on the hands and feet.
HFMD is highly contagious affecting about half of those exposed. It is common among children under five years of age, but adults may be affected also. Gums, tongue, buccal mucosa up to the uvula and tonsils may have lesions, which lasts for up to one week. They are rarely tender or itchy. They may occur on the palms, soles of feet, arms, legs, buttocks, and face.