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Hand Foot and Mouth Disease

Hand, foot, and mouth disease (HFMD) is a common, typically self-limited viral syndrome in children and adults. HFMD is seasonal with individual cases and regional outbreaks usually occur in the spring, summer, and fall. In the United states, most cases involve children less than 4 years of age. Adults can also be affected, especially if they were in contact with children in childcare. Infected patients continue to shed the virus for a long time, making hand hygiene and environmental control measures in health care settings and daycare centers of vital importance, to prevent spread of the infection.

 HFMD is marked by fever, oral ulcers and papulovesicular rash affecting the palms of the hands, soles of the feet and buttocks. Skin lesions can be either asymptomatic or tender and painful. Desquamation can follow the rash. Symptoms usually last less than one week. Incubation period is 3 to 5 days with a prodrome that may include fever, malaise, abdominal pain, and myalgia 

HFMD is caused by infection with a variety of viruses in the genus Enterovirus. The most common strains that cause HFMD are coxsackievirus A16 and enterovirus 71. Coxsackievirus A6 is becoming more common. The rash of coxsackievirus A16 HFMD may be more extensive and severe. Clinical characteristics of HFMD caused by enterovirus 71 may be somewhat different, with smaller vesicles, diffuse erythema of the trunk and limbs, and higher fever (temperature ? 39°C [102.2°F] for more than 3 days).  Many other coxsackievirus strains have been detected, including A5, A7, A9, A10, B2, and B5.

Neurologic and cardiopulmonary complications are more often associated with enterovirus 71 infection. Neurologic manifestations associated with enterovirus 71 infection include aseptic meningitis, a poliomyelitis-like syndrome, brainstem encephalitis, neurogenic pulmonary edema, opsoclonus-myoclonus syndrome, cerebellar ataxia, Guillain-Barré syndrome, and transverse myelitis.

Atypical HFMD associated with coxsackievirus A6 is emerging in the United States. Cases may occur in the winter months and have more widespread skin involvement including the antecubital and popliteal fossae.

A 2012 meta-analysis found that an elevated white blood cell count and hyperglycemia could be clinically useful in distinguishing benign from severe HFMD.

In mild cases of HFMD, particularly in patients with a high probability of having the disease based on their clinical characteristics and sick contacts, laboratory testing is not necessary. Testing is usually reserved for severe cases and public health investigation of outbreaks. Viral culture is the gold standard for diagnosing HFMD, but the final results can take nearly a week. Newly developed IgM-capture enzyme-linked immunosorbent assays (ELISAs) for coxsackievirus A16 and enterovirus 71 are available. In the first week of disease, the IgM detection rate is 90.2% for enterovirus 71 and 68% for coxsackievirus A16. Polymerase chain reaction testing is faster and is more sensitive in detecting central nervous system infection.

Enteroviruses initially replicate in the gastrointestinal tract. Viremia precedes invasion of the skin and mucous membranes. Plasma can be tested for IgM antibody. Throat and vesicle specimens are preferred for culture and PCR.

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