Ask the Doctors: Hand-foot-and-mouth disease exposure common in schools
A: Hand-foot-and-mouth disease (HFMD) is very common. It occurs most often in infants and children younger than 7 years of age and is caused by one of 16 types of enterovirus. Outbreaks are more likely in the late summer and early fall, when children are starting a new year of school or preschool.
Because the viruses that lead to HFMD are largely intestinal, they're usually passed via stool. Small amounts of the virus then make it onto the hands of the child or someone changing the child's diaper. The virus passes from one individual to another when it ends up on food, the fingers or the pacifier of another child, ending up in the mouth. The fecal-oral transmission is the most common way the virus infects others, but it can also be passed through oral secretions, through coughing, and through the fluid from the blisters seen in hand-foot-and-mouth disease.
Regardless, the virus makes its way down to the lower intestine, spreading to the lymph nodes and from there to the rest of the body. The typical time that it takes for the enterovirus to be ingested and for the first symptoms to appear is three to five days.
Symptoms of the disease begin with mouth or throat pain or the refusal to eat. The most striking symptom of hand-foot-and-mouth disease is the blisterlike rash that occurs both within the mouth and on the hands and feet; such blisters can also appear on the legs, arms and buttocks. The lesions are normally not painful and resolve in three or four days. Some species of enterovirus also cause fever, nausea and vomiting. Rarely, enteroviruses can lead to dehydration, viral meningitis or heart inflammation.
I can understand the worry that your school — and you — have regarding this infection. As I noted, the incubation period is typically three to five days, but one study of an outbreak at a day care showed that children were infectious up to seven days. And, not to make you overly worried, but some enteroviruses can be passed in the stool up to 10 weeks after infection.
I would ask school officials at which date the infected child began having symptoms of HFMD. If it was more than five days ago, I would be less concerned about your child now developing the disease.
However, because the virus can be shed long after disease, I would stress the importance of hand-washing. If your daughter does get hand-foot-and-mouth disease, the symptoms likely will not last long, and any discomfort can be treated with acetaminophen or ibuprofen. Watch for warning signs of potential complications, such as listlessness, severe headache or neck stiffness. Consult your pediatrician if your child has these symptoms.
Also, if your daughter does become infected, make sure to practice good hygiene at home, so the virus does not pass to you or other family members.
Robert Ashley, M.D., is an internist and assistant professor of medicine at the University of California, Los Angeles.
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