"What's wrong, honey?
"My mouth hurts, mommy."
"Maybe you're just getting a new tooth. I'll give you a lollipop."

The young child declines the offer, and continues to complain about pains in her mouth. Later in the evening at dinnertime, she doesn't feel like eating since she has a sore throat. A thermometer registers a mild fever. Her parent also notices that she has a rash on the palms of her hands. What's going on?

Could it be chicken pox? No, she was vaccinated a few years ago and there hasn't been a case of it at her school this year. Is it measles? No, she has the vaccine for that too. Could she have walked through poison ivy while we were walking through the park a few days ago? Or maybe it was the mosquitoes that have been unusually prolific during this hot, humid summer. Whatever it is, she needs to see the doctor.

After a visit to the doctor, she was diagnosed with hand, foot and mouth disease, along with many others of her age in an epidemic.

The disease tends to occur in outbreaks, such as in the United States, where epidemics tend to occur every 3 years 1. Countries in the Western Pacific Region such as China, Malaysia, Australia and Brunei Darussalam also have a record of epidemics2. Deaths from the disease can occur in severe cases due to pulmonary edema, pulmonary hemorrhage 2 or encephalitis 3. Dehydration due to fever or diarrhea is another risk, especially in children younger than 6 months 4. Therefore, replacing water and electrolytes during the disease can help them recover faster. Very rarely, young children with HMFD can lose nails from the fingers or toes. The nails will grow back after the disease has passed. 3

Unfortunately, there is no specific treatment for HFMD, since it is a viral disease. Antibiotics are ineffective against viruses. Similar to the common cold, only the symptoms are treated with OTC medications for pain and fever. Mouth sprays, gels or lozenges containing benzocaine or menthol can help reduce painful mouth sores. Fortunately, this disease lasts a short time. Lesions on the hands and feet last 5-10 days, and then heal in 5-7 days 5.

HFMD can be diagnosed by observing a specific combination of symptoms:

  • patient age - HFMD infection is typically limited to children 10 years or younger, and most frequently in children younger than 5 years 4.
  • fever - a fever is usually followed by lack of appetite and then painful mouth or skin sores 4.
  • location of rashes - skin irritation occurs on the palms of hands, soles of feet, buttocks and inside of the mouth.
  • type of lesion - HFMD produces different types of lesions on the body. Mouth lesions will be vesicular. That is, the lesion will have a raised and inflamed red perimeter surrounding a whitish center much like a cold sore ulcer 10. These lesions are painful rather than itchy.
HFMD shares many symptoms of other childhood diseases, such as:
  • chicken pox - produces nausea, fever, headache, sore throat, and rashes. However, HFMD rashes are not itchy.
  • allergic reaction to food - shellfish, milk, wheat, peanuts, soy and tree nuts can provoke allergic responses, but these usually occur within 2 hours of ingesting the allergen and produce swelling or gastrointestinal upset 6.
  • allergic reaction to plants - poison ivy, poison oak and poison sumac secrete urushiol, an irritating oil. Contact dermatitis occurs 24 hours or later after the initial exposure, and leads to intensely itchy fluid-filled boils 7. However, urushiol dermatitis does not cause the fever common in HMFD. Also, the skin lesions caused by HFMD are small and dispersed, unlike the blistering boils of urushiol dermatitis. Poison ivy takes up to 6 weeks to resolve, longer than the 2 weeks for HFMD.
  • insect bite - mosquitoes, chiggers, lice, bedbugs and even spiders can cause small skin wheal where they have bitten. This type of dermatitis can be intensely itchy, but is usually localized to a small area. The reaction also lacks a fever or sore throat.
  • strep throat - can cause fever and painful sore throat, but not rashes. Enlarged lymph nodes and a positive test result for streptococcal bacteria can confirm a diagnosis.
  • detergent dermatitis - some soaps or detergents can irritate skin, but this creates a uniform rash and not localized wheals. The rash will resolve after clothes are washed in a different or hypoallergenic detergent.

Two viruses in the genus Enterovirus cause HFMD. These viruses are named for replicating in the enteric, or digestive tract, and replicate best at 37 C 8. This genus is in the family Picornaviridae, which include viruses that infect all people across the world, and cause other diseases like poliomyelitis; aseptic meningitis; myocarditis; and hepatitis 89.

Coxsackievirus A16 (CV-A16) is the most common form, which is usually mild 1113. Its three genoypes A, B and C 13 have been studied, but with less attention possibly due to its low mortality rate. Human enterovirus 71 (HEV71) is a more severe form 13 that can cause encephalitis 11 and also has several genogroups A, B and C with further subgenogroups that have been observed in southeast asia 212.

While there is no vaccine or current treatment for HFMD, hand-washing can prevent spreading the disease during an outbreak. Routine hand-washing or use of sanitizers can prevent the spread of the virus that is usually transferred to mucosal membranes.

References


1 http://emedicine.medscape.com/article/1132264-overview#a0199
2 http://www.wpro.who.int/NR/rdonlyres/E803F3C4-420B-46A2-B2E6-778B52A71F83/0/GuidancefortheclinicalmanagementofHFMD.pdf
3 http://www.cdc.gov/hand-foot-mouth/about/
4 http://www.babycenter.com/0_hand-foot-and-mouth-disease_1614.bc
5 http://www.insted.in/ejournal/review34.pdf
6 http://en.wikipedia.org/wiki/Food_allergy
7 http://en.wikipedia.org/wiki/Urushiol-induced_contact_dermatitis
8 http://en.wikipedia.org/wiki/Picornaviridae
9 http://jid.oxfordjournals.org/content/185/6/744.full
10 http://emedicine.medscape.com/article/802260-overview
11 http://infectiousdiseases.about.com/b/2009/04/08/is-hand-foot-and-mouth-disease-deadly.htm
12 http://www.academicjournals.org/jgmv/PDF/pdf%202011/Apandi%20et%20al.pdf
13 http://jcm.asm.org/content/45/1/112.full


See also

KFL&A Public Health: Hand, foot and mouth disease

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