Deep Dive
What causes it
HFMD is a common, mild viral illness. It spreads very easily. It is usually caused by coxsackievirus A16, an enterovirus. Enterovirus A71 and coxsackievirus A6 also cause it. It is not the same as foot-and-mouth disease. That is a different virus, and it affects only animals. Children cannot get it from farm animals. It is most common in children under 5, but it can happen at any age. Clusters in adults are unusual, but they happen.
Incubation period
Symptoms usually appear 3 to 5 days after exposure.
Symptom progression
Often begins with fever, sore throat and a general unwell feeling. Painful sores then develop in or around the mouth. They are often the most distressing part, and the reason some children stop eating and drinking. A rash of flat red spots or blisters follows on the palms and soles, and sometimes the buttocks, legs, or around the mouth. In children it is usually not itchy. Symptoms are worst in the first few days and settle over roughly a week. Now and then a nail comes off a few weeks after recovery.
Possible complications
HFMD is almost always mild and clears on its own, and serious problems are rare. The one practical hazard is dehydration. Painful mouth sores can make a child unwilling to drink, and in a small child fluid loss is the thing to watch. Now and then a fingernail or toenail comes off a few weeks after recovery. That is a CDC-documented finding and a harmless one, more often after coxsackievirus A6, and the nail grows back on its own. Very rarely, enterovirus A71 is linked to more serious illness of the nervous system.
Treatment information
There is no specific treatment and no vaccine, and antibiotics do nothing against a virus. Care is all comfort, and above all fluids, because the painful mouth is what causes dehydration. Cold and soft foods go down better than warm, salty, spicy or sour ones. For fever and pain, use a product suited to the child's age that a provider or pharmacist has advised. Aspirin is not given to children. The rash needs no treatment, and blisters should not be broken on purpose.
Special populations
Pregnancy
HFMD is usually mild in pregnancy. Talk over any concerns with a provider. That matters most around the time of birth, when infection in a newborn calls for more care.
Pediatric
This is above all a young-childhood illness, and it spreads fast in childcare and school. The main thing to watch is fluids. A child with painful mouth sores can slip into dehydration, and that is the reason HFMD sometimes needs medical care.
Elderly
Adults can get HFMD, usually mildly, though clusters are unusual. Care is the same - comfort and fluids.
Immunocompromised
People with weak immune defenses may have a longer or harder course. They should ask for advice if symptoms are unusually bad.
HFMD spreads readily among young children in ordinary settings and says nothing about a family's cleanliness - shedding continues for weeks to months and many carriers have no symptoms, so exposure is often unavoidable. A parent who could not stop it spreading did not fail; it is not fully containable. This card does not assign blame.
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