Hand-foot-and-mouth (HFM) disease is a viral syndrome with a distinct exanthem-enanthem.
This clearly recognizable syndrome is characterized by vesicular lesions on the mouth and an exanthem on the hands and feet (and buttocks) in association with fever. See the images below.
Hand-foot-and-mouth disease is caused by a group of RNA viruses called enteroviruses. The most commonly implicated enterovirus is coxsackievirus A16.  However, coxsackieviruses A5, A9, A10, A16, B1, and B3; human enterovirus 71 (HEV71); as well as herpes simplex viruses (HSV) can cause the illness.
Cases are commonly spread via the fecal-oral or oral-oral route. Respiratory droplet transmission also may occur but is less likely. Typically, the virus seeds the GI tract via the buccal mucosa or the ileum. Over the next 72 hours (accounting for the incubation period), a viremia is established via spread through nearby lymph nodes. 
Distribution of this disease is worldwide, with a peak incidence in the summer and fall in temperate climates and with no seasonal pattern in the tropics.
The largest population-based study of the epidemiology of hand, foot, and mouth disease was conducted in China to better inform vaccine and other interventions. Between 2008 and 2012, the Chinese Center for Disease Control and Prevention recorded 7,200,092 probable cases of hand, foot, and mouth disease (annual incidence, 1·2 per 1000 person-years from 2010-12). Mortality (rare in developed countries) and incidence were highest in children aged 12-23 months. 
This illness has, essentially, a full recovery rate. However, HEV71 has been recently implicated in several large outbreaks in the Far East with severe complications and deaths. Complications are rare, but as with any pruritic rash, a secondary skin infection may occur.
Severe complications may occur when CNS or cardiopulmonary involvement is present. These sequelae include dysphagia, limb weakness, cardiopulmonary failure, and even death. Although death is very rare, it is most often due to pulmonary hemorrhage or edema.
Enteroviruses as a group are a cause of aseptic meningitis and encephalitis; however, Hand-foot-and-mouth disease is not usually associated with meningitis. 
Males and females are affected with equal frequency. Males are more likely to become symptomatically ill.
Hand-foot-and-mouth disease, as well as severe disease complications, are more common among infants and children younger than 5 years.