Dr. Jeff Hersh: About hand, foot and mouth disease
Q: My 3-year-old’s playmate was just diagnosed with hand, foot and mouth disease. Is this contagious?
A: Hand, foot and mouth disease (HFMD) is due to an infection from an enterovirus (a virus that can live in the digestive track), most commonly a Coxsackie virus. Enteroviruses include polioviruses and non-polioviruses (Coxsackie, hepatitis A and others).
Enteroviruses are contagious. They are transmitted via the fecal-oral route due to poor hygiene virus from someone’s stool is transferred to an object or to their hands and then passed to a new patient who ingests the virus, inhaling infectious respiratory secretions from an infected person sneezing or coughing or from contact with the fluid from skin blisters via ingestion or less likely inhalation. After infection the virus incubates for several days as it multiples in the respiratory tract or small intestine depending on the mode of transmission.
There are over 10 million infections from enteroviruses each year in the U.S., maybe as many as 50 million, and up to a quarter of these are due to a Coxsackie virus. Up to 80 percent of adults have antibodies to at least one type of enterovirus, having been exposed in the past. Coxsackie virus is most common in children age 5 and younger, although older children and adults get it as well. About 90 percent of infections from Coxsackie virus either cause no symptoms or cause only non-specific flu-like symptoms such as fever, malaise, body aches and/or sore throat. However, the other 10 percent of the time other conditions result from Coxsackie virus infection.
Group B Coxsackie viruses can affect the heart, muscles, pleura (the sack around the lungs), the pancreas and/or liver, causing myocarditis (inflammation of the heart), pericarditis (inflammation of the sac around the heart), pleurodynia (pain in the chest or abdomen from inflammation of the muscles there) or hepatitis (inflammation of the liver).
Group A Coxsackie viruses typically affect the skin and/or mucous membranes. They can cause herpangina (with symptoms of fever and rash/sores in the throat), hemorrhagic conjunctivitis (an inflammation of the conjunctiva, the clear membrane that covers the eye) or HFMD.
Hand, Foot and Mouth Disease should not be confused with hoof and mouth disease which infects cloven foot animals such as cows, sheep and swine, and is a totally different infection that does not affect humans.
The disease initially start with fever and flu-like symptoms. Within a couple of days, red spots in the mouth develop into sores, typically involving the gums, inside the cheeks and/or the tongue, as well as a non-itchy red rash which can be flat or raised on the hands/palms and/or feet/soles. Not everyone with HFMD has all the symptoms. The symptoms typically last several days and resolve on their own.
The diagnosis of HFMD is made based on the history and physical examination; no further testing is usually needed. Treatment is aimed at minimizing the symptoms with drugs like acetaminophen for fever and giving fluids to prevent dehydration as the sore mouth can decrease oral intake.
Uncommonly, Coxsackie virus can cause severe illness, including those already noted above. Furthermore, meningitis (inflammation of the lining around the brain and spinal cord) and encephalitis (inflammation of the brain) can complicate infection from Coxsackie infections. These more severe infections may be treated in the hospital with supportive care (there are no specific medications to treat Coxsackie infections), although there are some reports that myocarditis (and possibly other severe cases) may benefit from intravenous immunoglobulin therapy. Verification of the diagnosis for more severe infections is usually done by laboratory analysis (isolation of the virus in cell cultures or a specialized genetic test called PCR) of fluids from the patient (such as a throat swab, stool specimen or fluid from the blisters).
There is no vaccine to prevent Coxsackie virus infection. Since this infection most commonly occurs in children, it is important to keep infected children out of daycare or school because they can be infectious up to several weeks after their symptoms resolve. Encourage good hand washing and disinfect commonly touched surfaces. Although infection from a serotype of Coxsackie virus gives lifelong immunity, it is only immunity for that specific serotype; therefore it is still possible to become infected from other serotypes.
Jeff Hersh, Ph.D., M.D., can be reached at DrHersh@juno.com.