What is Hand, Foot, and Mouth Disease?
Hand, foot, and mouth disease (HFMD) is a typical viral sickness that mainly occurs in infants and children, but can also affect adults. The infection comes from a virus and often involves symptoms on the hands, feet, and mouth. However, it can sometimes also affect the genitals and buttocks.
The hand, foot, and mouth disease is primarily caused by a virus called coxsackievirus A type 16. Yet, other versions of the coxsackievirus can cause the infection too. Especially in the western Pacific, this disease has been associated with another virus called enterovirus.
The coxsackievirus belongs to a group of viruses named the Picornaviridae family, which are composed of non-enveloped single-stranded RNA viruses. That’s just a scientific way of saying they’re a particular type of virus that can cause infections.
What Causes Hand, Foot, and Mouth Disease?
Hand, foot, and mouth disease is a common illness caused by a group of viruses, mainly from the Enterovirus family. The primary culprits behind this disease are two specific types of coxsackieviruses, named A16 and enterovirus A71.
Recently, another coxsackievirus, named A6, has also been identified as a cause behind cases of hand, foot, and mouth disease in the United States and around the world. Another type of the virus, coxsackievirus A10 is associated with severe form of the disease.
Fewer instances of the disease have been linked to other types of coxsackieviruses like A4 to A7, A9, B1 to B3, and B5. Nevertheless, they are still associated with this disease, but are less common causes.
Risk Factors and Frequency for Hand, Foot, and Mouth Disease
This viral infection is not confined to one specific region, but rather it is a global issue. Children, especially those younger than seven, are more likely to get infected, leading to outbreaks in places like daycares, summer camps, or even within families. Most cases occur in late spring and early summer, and studies indicate that increasing temperatures and humidity can spike the incidence of this infection.
- More than 90% of Hand, Foot, and Mouth Disease cases occur in children under five.
- The death rate from this infection is about 0.03%.
- In 2021, French officials reported a rapid rise in cases, with over 3,400 recorded.
- Though most cases were traced back to the Enterovirus, some atypical cases were linked to Coxsackievirus A6 and A16.
- In the United States, Coxsackievirus A6 is the leading cause of Hand, Foot, and Mouth Disease.
Signs and Symptoms of Hand, Foot, and Mouth Disease
Hand, foot, and mouth disease, often referred to as HFMD, starts with minor symptoms like low-grade fever, loss of appetite, and a feeling of general uncomfortableness or fatigue. A common initial symptom is pain in the mouth or throat due to sores occurring inside the mouth. These sores are small, blister-like spots that are surrounded by redness. Over time, these blisters rupture to form shallow ulcers with a yellow-grey base surrounded by a red outline. These ulcers are generally not painful and do not itch.
These skin symptoms, or exanthems, can present as flat or raised spots, or can even be blister-like. These skin spots are usually about 2 to 6 millimeters in size and they typically don’t cause any discomfort. The spots last for about ten days and usually don’t leave a scar after healing. You’ll find these spots on the back of the hands, feet, buttocks, legs, and arms. Oral symptoms often include ulcers in the cheeks and on the tongue but can also appear on the soft part of the roof of the mouth.
- Low-grade fever
- Reduced appetite
- General malaise (discomfort)
- Mouth or throat pain
- Sores or ulcers in the mouth
- Non-painful, non-itchy skin spots
Aside from the typical features, HFMD can also show some unusual signs such as aseptic meningitis, an inflammation of the membranes that cover the brain and spinal cord. The virus causing HFMD can sometimes infect the central nervous system and can lead to other serious health conditions like encephalitis, a polio-like syndrome, acute transverse myelitis which is an inflammation of the spinal cord, Guillain-Barre syndrome, benign intracranial hypertension which is an increase in pressure around the brain, and acute cerebellar ataxia which affects coordination.
Testing for Hand, Foot, and Mouth Disease
Diagnosing hand, foot, and mouth disease typically involves a doctor’s evaluation and understanding of the symptoms, rather than relying primarily on laboratory testing. However, lab tests can still be useful in certain circumstances. For example, the virus responsible for this illness can be found in stool samples for about six weeks after the infection begins, though it can be found in the mouth and throat for a shorter time, generally less than four weeks.
Light microscopy, a method using a specific type of microscope, can be used to examine biopsies or scrapings of the blisters caused by the disease. This can help distinguish hand, foot, and mouth disease from other illnesses that cause similar blisters, like chickenpox and oral herpes.
Serology tests, which detect antibodies in the blood, are not typically used to diagnose hand, foot, and mouth disease, as they’re not particularly sensitive. However, they can still be useful in tracking a patient’s recovery, as the levels of a type of antibody known as IgG can increase as the body fights off the virus.
In some medical centers, serology tests are used to differentiate between two types of viruses that can cause hand, foot, and mouth disease: enterovirus 71 and coxsackievirus. This is because knowing the specific type of virus involved can have implications for prognosis, or the expected course and outcome of the disease.
Today, many medical centers have access to polymerase chain reaction (PCR) testing, a type of test that can detect and identify specific genetic material from a virus. This test can be used to confirm a diagnosis of hand, foot, and mouth disease caused by coxsackievirus. A swab of the blister can detect either coxsackievirus or enterovirus using real-time PCR testing.
Treatment Options for Hand, Foot, and Mouth Disease
Hand, foot, and mouth disease is a mild illness that typically goes away on its own within a week to ten days. The primary goal of treatment is to manage symptoms and keep the patient comfortable. Over-the-counter drugs like NSAIDs and acetaminophen can help reduce pain and fever. Staying hydrated is also crucial. A home remedy of gargling with a mixture of liquid ibuprofen and liquid diphenhydramine can help soothe mouth ulcers. Steroids, however, could potentially worsen the condition.
In the case of more severe forms of hand, foot, and mouth disease caused by a virus called enterovirus 71, researchers have been hard at work developing treatments. While no drug has been officially approved yet, there are several promising candidates. These include molecular decoys, translation inhibitors, receptor antagonists, and replication inhibitors. Some studies have shown that an anti-viral agent called pleconaril might be effective, but it’s not yet licensed for use in treating hand, foot, and mouth disease. Reports also suggest that a drug called acyclovir might help, but this is still being explored in clinical trials.
There’s some good news in terms of prevention, though. Several vaccines against hand, foot, and mouth disease and the viruses that cause it are currently under development. A few vaccines have already been developed and approved for use in China, with promising results. One study of a vaccine called EV71 C4a showed it was 94.7% effective in preventing the disease, with the effects lasting for about two years. There are also other types of vaccines — DNA vaccines, peptide vaccines, and subunit vaccines — but these are still going through clinical trials.
What else can Hand, Foot, and Mouth Disease be?
When trying to diagnose Hand, Foot, and Mouth Disease (HFMD), it’s important for doctors to also consider other conditions that can cause similar symptoms. These symptoms could include skin rashes and sores in the mouth. The conditions to consider might include:
- Erythema multiforme
- Herpangina
- Herpes simplex
- Herpes zoster
- Kawasaki disease
- Toxic epidermal necrolysis (TEN)
- Viral pharyngitis
- Rocky Mountain spotted fever
- Varicella zoster infection (chickenpox)
- Steven-Johnson syndrome
- Monkeypox
In the case of a monkeypox outbreak, it may be particularly challenging to tell the difference between monkeypox and HFMD.
What to expect with Hand, Foot, and Mouth Disease
Hand, foot, and mouth disease generally has a great prognosis, which means people with this illness are expected to recover fully. Most patients get better within a few weeks with no lingering effects. The acute stage of the illness, which is when symptoms are most severe, usually lasts between 10 to 14 days, and the infection rarely comes back or lingers.
However, some people with hand, foot, and mouth disease can develop serious complications:
* Long-lasting mouth inflammation is associated with painful ulcers. This pain can be severe enough to make eating difficult, which can lead to dehydration, especially in young children.
Aseptic meningitis, which is an inflammation of the protective membranes of the brain and spinal cord, can also happen but is more common with enterovirus 71. This virus is associated with a higher likelihood of affecting the nervous system compared to another type of virus called coxsackievirus. The person can develop conditions like acute cerebellar ataxia, which affects balance and coordination, conditions similar to polio, brain inflammation, benign intracranial hypertension, which is a buildup of pressure around the brain, and Guillain-Barre syndrome, which affects the nerves.
The virus is believed to cause damage to the gray matter in the brain, resulting in disrupted motor functions, which are movements controlled by the brain. Coxsackievirus, while rare, can also cause pneumonia, heart inflammation, pancreas inflammation, and fluid buildup in the lungs. Some studies suggest that coxsackievirus infections might be related to spontaneous abortions as well.
Possible Complications When Diagnosed with Hand, Foot, and Mouth Disease
Pneumonia, inflammation of the heart and pancreas, and fluid buildup in the lungs are rare but possible complications associated with Hand, Foot, and Mouth Disease (HFMD). Other major organs can also be affected. These complications are uncommon but important to note.
A large review of children with HFMD suggested that extreme tiredness, fluid or bleeding in the lungs, seizures, difficulty breathing, and coma can increase the risk of death from the disease.
In studies summarizing data on HFMD caused by the enterovirus 71 strain, the death rate was found to be 1.7%.
Potential Complications and Risk Factors:
- Pneumonia
- Inflammation of the heart
- Inflammation of the pancreas
- Fluid buildup in the lungs
- Affected other major organs
- Extreme tiredness
- Fluid or bleeding in the lungs
- Seizures
- Difficulty breathing
- Coma
Preventing Hand, Foot, and Mouth Disease
Teaching patients and parents is crucial in stopping the spread of hand, foot, and mouth disease (HFMD) among children and also from children to adults. It’s been proven that washing your hands is a great way to prevent the spread of this disease. A community study found that when people received better education about how to wash hands properly, there was an increase in both parents’ and children’s overall cleanliness. This increased cleanliness then led to fewer cases of HFMD in the group studied.
Parents especially should be instructed to keep their child away from individuals with weakened immune systems (people who are immunosuppressed) because these people have a higher chance of becoming seriously ill if they catch HFMD.
