Hand, foot, and mouth disease is a contagious infection that causes blisters and sores. It tends to occur most often in young children.

Hand, foot, and mouth disease (HFMD) is a highly contagious infection. It’s caused by viruses from the Enterovirus genus, most commonly the coxsackievirus.

These viruses can spread from person to person through direct contact with unwashed hands or surfaces contaminated with feces. It can also be transmitted through contact with a person’s saliva, stool, or respiratory secretions.

HFMD is characterized by blisters or sores in the mouth and a rash on the hands and feet. The infection can affect people of all ages, but it usually occurs in children under age 5.

It’s generally a mild condition that goes away on its own within several days.

Symptoms begin to develop 3 to 6 days after first getting the infection. This period is known as the incubation period. When symptoms do appear, you or your child may experience:

A fever and sore throat are usually the first symptoms of HFMD. The characteristic blisters and rashes show up later, usually 1 or 2 days after the fever begins.

The rash usually looks like flat red spots. The spots can be harder to see on darker skin tones, so it’s easier to check the palms of hands and the bottom of feet where the condition may be more noticeable.

Lesions can appear on all surfaces of your hands and feet, but this is one of the few times a rash on your palms and soles occurs, which is why it’s easy to identify.

Most children with HFMD will also have painful sores in the mouth. Check their tongue — including the sides — and throat.

HFMD is often caused by a strain of coxsackievirus, most commonly coxsackievirus A16. The coxsackievirus is part of a group of viruses called enteroviruses. In some cases, other types of enteroviruses can cause HFMD.

Viruses can be easily spread from person to person. You or your child may get HFMD through contact with a person’s:

  • saliva
  • fluid from blisters
  • feces
  • respiratory droplets that are sprayed into the air after coughing or sneezing

HFMD can also be transmitted through direct contact with unwashed hands or a surface containing traces of the virus.

Young children have the highest risk for getting HFMD. Risk increases if they attend day care or school, as viruses can spread quickly in these facilities.

Children usually build up immunity to the disease after being exposed to the viruses that cause it. This is why the condition rarely affects people over age 10.

However, it’s still possible for older children and adults to get the infection, especially if they have weakened immune systems.

A doctor can often diagnose HFMD by performing a physical exam. They’ll check your mouth and body for the appearance of blisters and rashes. The doctor will also ask you or your child about other symptoms.

The doctor may take a throat swab or stool sample to test for the virus. This will allow them to confirm the diagnosis.

In most cases, the infection will go away without treatment in 7 to 10 days. However, your doctor may recommend certain treatments to help ease symptoms until the disease has run its course. These can include:

  • prescription or over-the-counter topical ointments to soothe blisters and rashes
  • pain medication, such as acetaminophen or ibuprofen, to relieve headaches
  • medicated syrups or lozenges to ease painful sore throats

You shouldn’t give aspirin to children for viral infections. Aspirin can lead to Reye’s syndrome in children.

Certain at-home treatments can also provide relief from HFMD symptoms. You can try the following home remedies to help make blisters less bothersome:

  • sucking on ice chips or popsicles
  • eating ice cream or sherbet
  • drinking cold beverages
  • limiting citrus fruits, fruit drinks, and soda
  • limiting spicy or salty foods

Swishing warm salt water around in your mouth may also help relieve the pain associated with mouth blisters and throat sores. You can do this several times a day or as often as needed.

You or your child should feel completely better 7 to 10 days after the initial onset of symptoms. Getting the infection again is uncommon. The body usually builds up immunity to the viruses that cause the disease.

Call a doctor immediately if symptoms get worse or don’t clear up within 10 days. In rare cases, coxsackievirus can cause a medical emergency.

Potential complications of HFMD include:

Practicing good hygiene is the best defense against HFMD. Regular handwashing can greatly reduce your risk of getting this virus.

You can teach your children how to wash their hands using hot water and soap. Washing your hands after using the restroom, before eating, and after being out in public is important.

Children should also not put their hands or other objects in or near their mouths.

It’s important to disinfect any common areas in your home on a regular basis. Try cleaning shared surfaces first with soap and water, then with a diluted solution of bleach and water.

You should also disinfect toys, pacifiers, and other objects that may be contaminated with the virus.

If you or your child experience symptoms such as a fever or sore throat, stay home from school or work. It’s best to avoid contact with others once the blisters and rashes develop. This can help you avoid spreading the disease to others.

Q:

My daughter has HFMD. How long is the virus contagious, and when can she start going back to school?

Anonymous patient

A:

People with HFMD are most likely to pass on the infection during the first week of the illness. They can sometimes still pass it on for a few weeks after symptoms go away, but this is less likely.

Your child should stay at home until her symptoms resolve. She may then return to school, but she’ll still need to limit close contact with her peers, including allowing others to eat or drink after her.

She should wash her hands frequently and try not to rub her eyes or mouth, as the virus can be transmitted through body fluids.

Mark Laflamme, MDAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.