A 4-year-old boy presents to a free clinic for homeless families with a low-grade fever and lesions on his hands and feet (Figures 113-1 and 113-2). The mother notes that two other kids in the transitional living center also have a similar rash. Upon further investigation, mouth lesions are noted (Figure 113-3). The mother is reassured that this is nothing more than hand, foot, and mouth disease and will go away on its own. Treatment includes fluids and antipyretics as needed.
Typical flat vesicular lesions on the hand of a 4-year-old boy with hand, foot, and mouth disease. (Used with permission from Richard P. Usatine, MD.)
Foot of the boy in Figure 113-1. Lesions tend to be on palms and soles, fingers, and toes. (Used with permission from Richard P. Usatine, MD.)
Mouth lesions in same boy appear as small ulcers on the lips and oral mucosa. (Used with permission from Richard P. Usatine, MD.)
Hand, foot, and mouth disease (HFMD) is a viral illness that may affect humans and some animals, and presents with a distinct clinical presentation. The disease occurs worldwide. In 2011 and 2012, an outbreak of a much more severe and atypical form occurred in the US.
Epidemics tend to occur every 3 years worldwide. In temperate climates, the peak incidence is in late summer and early fall.
HFMD generally has a mild course, but it may be more severe in infants and young children.1,2
There is no racial or gender predilection. Most cases affect children younger than 10 years old.3
Etiology and Pathophysiology
HFMD is most commonly caused by members of the enterovirus genus, especially coxsackie viruses. Epidemic infections in the US are usually caused by coxsackievirus A16, and less commonly by other coxsackievirus A strains, coxsackievirus B, or enterovirus 71.2,3 Sporadic cases occur caused by other coxsackie viruses.
HFMD is caused by a number of different enteroviruses around the world with different characteristics, but until recently outbreaks of an A6 strain have not been experienced in the US. Most HFMD cases worldwide are due to coxsackievirus A16.4,5
Outbreaks of strains of EV71 enterovirus producing large epidemics of HFMD with significant morbidity and mortality that have occurred recently in east and southeast Asia have not been seen in the US.5
In the fall of 2011 and early winter of 2012, 63 cases of apparent, but more severe HFMD from four US states ...