Hand, foot and mouth disease is a viral infection that is very common among children under five in Vietnam, and preschools are where it spreads most easily. Most children have a few days of fever, painful mouth ulcers and small spots or blisters on the hands, feet and bottom, then recover on their own. A small number develop serious complications, so knowing the warning signs matters more than knowing the name.
Families arriving from Europe, North America or Australia may know the illness only vaguely, while Vietnamese parents and teachers treat it seriously because the country has seen large outbreaks, including severe cases linked to a particular virus strain. This guide explains what the disease is, how to recognise it early, which signs mean going to hospital without delay, how it moves through a class and what to expect when your child can return. It does not replace a doctor’s examination, which is the right step whenever you suspect it.
What the disease is and why it is taken seriously here
Hand, foot and mouth disease is caused by a group of viruses called enteroviruses. The most common culprits are coxsackievirus A16 and enterovirus 71, often shortened to EV71. Both usually cause a mild illness, but EV71 is the strain more often linked to complications affecting the nervous system, heart and lungs. Several countries in Asia, Vietnam among them, have experienced outbreaks in which EV71 played a large role, which is why health authorities here monitor case numbers closely and issue warnings to schools.
The disease is not related to foot-and-mouth disease in cattle, despite the similar name. Humans are the only source. Adults can catch it too, often with few or no symptoms, which is one reason it keeps circulating.
Vietnam’s Ministry of Health has published clinical guidance that grades the disease into levels, from a mild form treated at home with monitoring up to severe forms needing intensive care. Parents do not need to learn the grading, but it explains why Vietnamese doctors may ask detailed questions about sleep, startle movements and vomiting even when the spots look mild. They are checking for early signs that the illness is moving beyond the mild level.
For international parents, the practical message is balanced. Most children recover in about a week with rest, fluids and comfort. A minority become seriously ill, sometimes quickly, and they usually show recognisable warning signs first. Watching closely during the first days is what makes the difference.
Early signs: what you may notice first
The illness often starts in a vague way, and the typical spots may appear a day or two after the fever. Children vary, and not every child shows every sign.
- A fever, often moderate, sometimes with tiredness, a sore throat or a poor appetite.
- Refusing food or drink, drooling more than usual or crying when eating, because of painful ulcers inside the mouth, on the tongue or gums.
- Small red spots or flat blisters on the palms, soles of the feet, knees or buttocks. They are often not itchy, which helps distinguish them from insect bites or heat rash.
- Irritability and poor sleep in a young toddler who cannot explain that their mouth hurts.
- In some children, mainly spots in the mouth with very little on the skin, or the other way round.
Because a sore mouth makes children refuse drinks, the main risk at home in a mild case is dehydration, especially in hot weather. Cool drinks, soft cool foods and frequent small sips are usually easier than a full cup. Check for wet nappies or regular urine as a simple guide to whether your child is drinking enough, and ask a doctor what pain relief is suitable and in what dose.
Warning signs that need a hospital without delay
These are the signs Vietnamese health guidance and doctors ask parents to watch for. If you see any of them, take your child to a hospital emergency department straight away rather than waiting for a clinic appointment.
| Warning sign | What it can look like at home |
|---|---|
| High fever that is hard to bring down or lasts more than two days | Temperature stays high despite the medicine your doctor advised, or keeps returning |
| Startle jerks or twitching, especially during sleep | Sudden jumps or jerks of the arms and body several times while dozing |
| Repeated vomiting | Vomiting several times, or unable to keep fluids down |
| Unusual sleepiness or irritability | Hard to wake, floppy, or crying in a way you cannot settle |
| Unsteady movement or weakness | Wobbly walking, trembling hands, a limb that seems weak, eyes looking in different directions |
| Breathing or circulation changes | Fast breathing, noisy breathing, pale or mottled skin, cold hands and feet |
None of these signs is something to manage at home. If you are unsure whether a movement counts as a startle jerk, a short video on your phone can help the doctor. In an emergency in Vietnam, the ambulance number is 115, though in heavy traffic a taxi or private car may reach a nearby hospital faster.
How it spreads through a preschool class
The viruses travel in saliva, nose and throat secretions, the fluid inside blisters and in stool. In a toddler room, that covers almost everything: shared toys that go into mouths, hands after nappy changes, tables, door handles and the water play tray. Children are most infectious in the first week of illness, but the virus can stay in stool for several weeks after they recover, which is one reason outbreaks are hard to stop completely.
Two details surprise many parents. The first is that alcohol hand gel is less reliable against these viruses than against many others, because enteroviruses do not have the fatty outer layer that alcohol breaks down easily. Washing with soap and running water, rubbing all surfaces of the hands, works better. The second is that some infected children and adults show few symptoms but can still pass the virus on, so a class can see new cases even when no visibly ill child has attended.
This is why preschools in Vietnam tend to respond to a case with cleaning as well as exclusion. Toys are washed, surfaces are disinfected with chlorine-based products commonly used in Vietnamese schools, and handwashing routines are tightened. If you hear that a class is being cleaned thoroughly after a case, that is a normal and sensible response, not a sign that something went wrong.
Looking after a mild case at home
Once a doctor has confirmed the illness and decided your child can be cared for at home, the job for the next week is mostly comfort, fluids and watching. The illness usually peaks over the first few days. The mouth tends to be most painful around the time the ulcers first appear, and then improves gradually as they heal.
Fluids come first. In a hot city, a toddler who refuses to drink for most of a day can become dehydrated faster than parents expect. Offer small amounts often: cool water, cool milk if your child tolerates it, or oral rehydration solution if the doctor suggested it. A spoon or a small cup may be accepted when a bottle or straw hurts. Note how often your child passes urine, because fewer wet nappies or very dark urine are signals to call the doctor.
Keep a simple log with times: temperature, medicine given and its dose as advised by the doctor, drinks, urine and any unusual movement during sleep. That log helps you see the trend instead of reacting to each hour, and it gives the doctor precise information if you need to go back. Sleep near a young child for the first nights if you can, since startle jerks during sleep are one of the warning signs doctors ask parents to watch for.
Siblings and visitors are the other concern. Keep cups, towels and toothbrushes separate, wash hands after every nappy change, and postpone playdates until the return period is over.
If there is a case in your child’s class
Schools usually inform parents when a case is confirmed, without naming the child. A calm, practical routine for the following week or two helps more than keeping your child home indefinitely.
- Check your child’s mouth, hands and feet in good light each morning and evening, and take their temperature if they seem unwell.
- Reinforce handwashing with soap at home, especially before meals and after the toilet or nappy changes.
- Keep cups, spoons and toothbrushes separate between siblings for a while.
- Wash toys that go in the mouth more often than usual, and clean bathroom surfaces regularly.
- If your child develops a fever or mouth ulcers, keep them home, tell the school and see a doctor for a diagnosis.
- Watch any younger baby in the family closely, since the youngest children are at higher risk of complications.
If your child is diagnosed, tell the school promptly. It lets them alert other families and step up cleaning, which protects everyone, including your child when they return.
Common beliefs and what is actually true
“Once a child has had it, they are immune.” Not completely. Several different enteroviruses cause the disease, and immunity to one does not protect against the others. A child can have it more than once, usually in a milder form.
“The spots are small, so it must be mild.” The amount of rash does not tell you how the illness will go. Serious complications are signalled by the warning signs listed above, not by the number of blisters.
“Antibiotics will speed it up.” Antibiotics treat bacteria and have no effect on viruses. Treatment is supportive: fluids, rest, comfort and close monitoring. Pharmacies in Vietnam may sell many medicines without a prescription, which makes it more important to follow a doctor’s advice rather than buying something to try.
“It is only a disease of poor hygiene.” Good hygiene reduces spread but does not make a school immune. Outbreaks happen in well-run preschools too, because toddlers share space and objects all day.
Returning to preschool after hand, foot and mouth disease
Vietnamese health guidance has commonly advised keeping children away from school and group activities for around ten days from the start of symptoms, and many preschools in Vietnam follow a period of that length. Guidance in some other countries is shorter and focuses on whether the child is well enough. Because of this difference, ask your school what it requires rather than relying on what a doctor or school told you in another country.
Some schools ask for a note from a doctor confirming that your child has recovered. Even when blisters have dried, your child may still carry the virus in stool for weeks, so the habits you built during the illness, especially handwashing after the toilet, are worth keeping long after the return date.
When your child goes back, tell the teacher how they have been eating and sleeping. Mouth ulcers can leave children wary of certain foods for a few days, and a teacher who knows this can offer cooler, softer food without pressure. A short return day, if the school allows it, can also help a child who has spent a week and a half at home ease back into the routine.
Câu hỏi thường gặp
Can adults catch hand, foot and mouth disease from their children?
Yes. Adults can be infected, though many have mild symptoms or none. Some develop a sore throat, fever and painful spots. Careful handwashing after nappy changes and before preparing food reduces the chance of passing it around the household, including to a younger baby.
Is there a vaccine for hand, foot and mouth disease?
Vaccines targeting EV71 have been developed and are used in some countries, but availability varies. Ask a vaccination clinic or your child’s doctor in Vietnam what is currently licensed and recommended here, rather than relying on information from another country.
How long is my child contagious?
Children are most contagious during the first week of symptoms, but the virus can remain in stool for several weeks afterwards. That is why schools set a return period and why handwashing after the toilet remains important even once your child seems fully recovered.
What can my child eat with painful mouth ulcers?
Cool, soft and bland foods are usually easiest, for example yoghurt, smooth porridge that has cooled, mashed fruit or chilled water. Salty, sour or spicy foods tend to sting. Drinking matters more than eating for a few days, so offer frequent small sips and ask a doctor about suitable pain relief.
Should I keep my child home if there is a case in their class but my child is well?
Usually that is not necessary, unless the school or health authorities ask families to. Watch your child closely for fever and ulcers, reinforce handwashing, and keep them home and see a doctor at the first signs. Ask the school how it is responding to the case.
Are blisters on the hands always hand, foot and mouth disease?
No. Insect bites, heat rash, eczema and other viral rashes can look similar to an untrained eye. A doctor can usually tell from the pattern of spots, the mouth and the history. Get a diagnosis rather than guessing, especially before sending your child back to class.