Hand-foot-and-mouth disease (HFMD) is a viral infection most commonly affecing children, the chracteristic sign is a rash affecting, as the name suggests, the hands, feet and mouth. In most cases the course of the disease is relatively benign but in some instances complications have been recorded
What causes hand-foot-and-mouth disease?
Hand-foot-and-mouth disease HFMD is commonly caused by enteroviruses, specifically the picarnovirus family1. Hand, foot, and mouth disease has been associated particularly with coxsackievirus A16-which continues to predominate as the cause of numerous outbreaks2. Although HFMD disease is one of the more common syndromes associated with coxsakievirus A16, other serotypes are sometimes isolated3. A4, AS, A9, and Al0 have also been implicated, as well as coxsackievirus B2 and B52. Enterovirus 71 (coxsakievirus group a) has been associated with a recent outbreak of HFMD disease in Taiwan1.
HFMD is chracterised by the areas of the body which developes a rash. The most frequent site of this rash is the mouth, where the tops of the spots are rapidly eroded, leaving ulcers. The rash on the hands and feet is vesicular (blister like), but the vesicles often have a curious liner or arc shape. The rash may initially appear as solid red raised spots which then develop the usual blisterlike appearance. Occasionaly the buttocks may be involved7.
Scattered lesions occur randomly in the mouth. About 85% of patients also develop sparse grayish vesicles (3-5mm diameter) surrounded by reddish skin on the back of the fingers, particularly in the areas around the fingernails or toenails and on the margins of the heels. Occasionally vesicles may appear on the palms, soles of the feet or in the groin area, particularly in children3.
HFMD also involves several days of fever and vomiting and the course of the disease is usually benign but may be followed by aseptic meningitis, encephalomyelitis (a disease of the brain and spinal cord) or even acute flaccid paralysis similar to paralytic poliomyelitis6. If no compilications develop patients will recover.
Enterovirus 71 has been responsible for localised outbreaks of disease involving small numbers of patients over several years and also for regional epidemics involving hundreds to thousands of persons within a single season. Presumed to be predominantly of fecal-oral spread, most symptomatic infections occur in children less than six years old. Young children have a disproportionately high number of cases associated with severe complications such as encephalitis (an inflammation of the brain) and motor paralysis. The spectrum of clinical illness has varied considerably amoung outbreaks of infection reported from different locations4.
In outbreaks, the highest attack rates are usually in young chldren but adults are also frequently affected, and intrafamilial spread is common3.
An outbreak of enterovirus infection occurred in Taiwan from late spring to early fall of 1998. Most of the pediatric infections presented as hand-foot-mouth disease (HFMD) and herpangina (fever and sore throat with white spots appearing on back of palate). A small portion of patients had symptoms of polio-like encephalitis and paralysis5. Although several enteroviruses were circulating in Taiwan during the 1998 epidemic, enterovirus 71 infection was associated with most of the serious clinical manifestations and with nearly all the deaths. Most of those who died were young1. The fatality rate from encephalitis was found to be around 14 percent6.
Enteroviral infections may be diagnosed by a combination of viral isolation and virus-specific serologic testing. Virus isolation is most specific if virus is recovered from the organ affected9. Virus from HFMD may be recovered from the stools, from throat secretions or from the vesicles