CLINICAL MATTERS
The Department of Health recently reported that 7,598 cases of hand, foot and mouth disease (HFMD) were diagnosed between Jan. 1 and Feb. 22, 2025. This is about three times the number of cases from the same period last year and is most likely an underestimation of the actual number of cases. As a parent, I was made aware of an outbreak of HFMD in my son’s school during the second week of February. The rapid spread of cases necessitated a shift to online learning for a week, along with reiteration of hygienic measures once classes resumed. The outbreak eventually abated and they have been back in class for a few weeks now, and thankfully my son never got infected. I also got a call from a friend who is a school physician in another school a week later, and she asked for help with their own HFMD outbreak. I referred her to the local government guidelines and I believe their outbreak is under control.
What is HFMD, and how is it best controlled? HFMD is caused by a group of viruses collectively known as enteroviruses. The name enterovirus means that these viruses live and multiply in the gut, but can affect other parts of the body as well. The two most common enteroviruses that cause HFMD are Coxsackievirus A16 and Enterovirus 71. HFMD typically affects school-age children and starts as a rash in and around the mouth and on the hands and feet – hence the name. It can also cause rashes in other body parts such as the groin and buttocks, but this is relatively rare. The rashes usually develop into blisters which can be itchy and painful. Aside from the rash, low-grade fever, cough, colds, and sore throat are common. Abdominal pain and diarrhea are also possible manifestations. Symptoms typically last seven to 10 days and most people recover with just supportive care.
The blister fluid is very contagious, as are respiratory secretions and stool from someone with an active infection. Inhalation of infected respiratory droplets from coughing and sneezing in close proximity to a patient and direct contact of infected fluid with mucus membranes of the nose and mouth are the main routes of infection. The virus can remain viable on surfaces such as walls and toys contaminated with infectious body fluids for up to several weeks. Touching these surfaces and transferring them to the nose and mouth with unwashed hands can result in infection.
Symptoms usually begin three to six days after exposure to an infected person’s infectious secretions or contact with a contaminated object. Outbreaks normally occur in crowded settings like kindergarten or elementary school classrooms where there may be a lot of close contact between children and with surfaces contaminated with viruses. Cases can rise quickly due to multiple people getting exposed, and can result in school closures depending on the local government rules.
HFMD is usually diagnosed based on clinical findings. The rash on the hands, feet, and mouth is typical of the disease and laboratory testing is often unnecessary. If the disease is suspected in someone with atypical symptoms, a viral culture or PCR can be done but the availability of these tests is very limited. There are no rapid tests for HFMD, and other laboratory findings are non-specific.
HFMD is often a self-limited illness and treatment is supportive and symptomatic. Anti-pyretics like paracetamol can help with fever and headaches. Antihistamines can help control itching and sneezing. Blisters should be cleaned regularly and inspected for signs of secondary bacterial infection. Soap and water are enough for cleaning the blisters. Using harsh disinfectants and antiseptics is usually not necessary and may just further irritate the skin. HFMD from Enterovirus 71 has been associated with encephalitis (brain swelling), viral meningitis, and cardiovascular complications such as myocarditis. These complications, especially encephalitis, have caused fatalities in some outbreaks. Coxsackievirus can also cause encephalitis, meningitis and myocarditis, but severe complications with this virus are less common than with Enterovirus 71. There are no effective approved antiviral medications for HFMD but some candidates are in development. The antiviral ribavirin is being studied but has shown mixed results in preclinical trials.
HFMD-infected people are most contagious during the first week of symptoms but can continue to shed virus in their respiratory secretions for up to three weeks. The virus is also shed through the stool, and live virus can continue to be excreted via this route for weeks to months. Control of HFMD can be achieved through good hygiene and early quarantine of cases during the most infectious phase of the disease. Frequent handwashing and cleaning of surfaces are essential in reducing the spread of HFMD. Wearing face masks among close contacts is not usually practical, especially for young children, but may help in outbreaks among older students. A “healthbreak” where classes are suspended or held online for at least one week may help control an outbreak when there are many simultaneous cases but the overall benefit of this measure remains uncertain. If this is done, all surfaces and toys in the classroom should be properly disinfected before classes resume. Adequate facilities for hand hygiene, whether with soap and water or hand sanitizer, should be provided to minimize residual transmission. Children who develop HFMD can usually return to school once the lesions are dry, but they can remain contagious from respiratory secretions and fecal shedding for weeks to months. This means that proper handwashing, hygiene, and cough etiquette remain of paramount importance in minimizing the risk of new infections.
Immunity to infection from the specific virus that caused an episode of HFMD is typically lifelong. However, since many viruses cause HFMD, a person can get the disease anew from a different enterovirus. A vaccine for Enterovirus 71 has been developed in China but is not widely available. Some Coxsackievirus vaccines are being studied but these are still in the testing stages. At the end of the day, the basic principles of infection control remain the most important interventions for preventing and controlling the spread of HFMD in our country at this time. The key is literally in our hands.