Genetic: Hand-Food-and-Mouth Disease

Definition

Hand-foot-and-mouth disease (HFMD) is a contagious virus infection most likely to affect children below the age of ten. Its most noticeable symptoms are sores in the mouth and a rash on the hands, soles of the feet, and sometimes the buttocks. HFMD should not be confused with foot-and-mouth (sometimes called hoof-and-mouth) disease, which is a virus infection that affects cattle, pigs, and sheep. Humans cannot get the animal disease, and they cannot transmit HFMD to household pets or other animals.

Description

Hand-foot-and-mouth disease is largely a disease of young children in the United States. It often spreads rapidly in schools, day care centers, and other places where large numbers of children may be in close contact. The viruses that cause HFMD belong to a group of viruses called enteroviruses, which get their name from the fact that they are commonly found in the human digestive tract. The two most common enteroviruses that cause HFMD are called enterovirus 71 (EV71) and coxsackievirus A16, named for the town in New York where it was first identified in 1948.

The enteroviruses that cause HFMD are spread by contact with the mucus, tears, saliva, blister fluid, or feces of an infected person. The most

common methods of transmission are contact with the unwashed hands of a person with HFMD or with a toy, drinking glass, or other object the infected person has touched. Infected children and adults are most contagious during the first week of illness; the virus can, however, remain in the intestines for about a month after the illness.

HFMD has an incubation period of three to seven days. The first symptoms of illness are usually fever and a sore throat, followed by loss of appetite. About two days after the fever begins, the patient develops painful sores in the mouth. A rash with blisters also appears on the palms of the hands, the soles of the feet, and sometimes on the buttocks or genitals. Some people have only the rash and some have only the mouth sores. The rash and mouth sores last for about a week or ten days and then clear completely.

Children and adults who have been infected with HFMD are immune to the specific virus that caused their symptoms after they recover. They can, however, develop a second case of HFMD if they are infected with a different enterovirus known to cause the disease.

Demographics

Hand-foot-and-mouth disease is a common disease around the world, with millions of cases each year. It is primarily a disease of young

children, although young adults sometimes get infected. Older adults rarely get HFMD unless they have weakened immune systems.

There are epidemics of HFMD in the United States about every three years, most often in late summer or early fall. The disease affects both sexes and all racial and ethnic groups equally.

Causes and Symptoms

Hand-foot-and-mouth disease is caused by at least fourteen different enteroviruses, the two most common in the United States being entero-virus 71 and coxsackievirus A16.

The most common symptoms of HFMD include:

• Low-grade fever (101°F [38.3°C])
• Sore throat
• Loss of appetite
• Painful reddish ulcers or blisters around or in the mouth or on the soles of the feet and palms of the hands
• Headache
• Tiring easily or sleeping more than usual
• Crankiness in infants and toddlers

Some children may also:

• Drool
• Develop muscle aches
• Have pains or cramping in the abdomen

Diagnosis

The diagnosis of hand-foot-and-mouth disease is usually based on the doctor's observation of the patient's age, history, and visible symptoms. Blood tests or other laboratory studies are rarely done because the illness is usually mild. It is possible to identify the viruses that cause HFMD by taking stool samples or by swabbing the patient's mouth and throat and culturing the virus in the laboratory, but these tests can take between two and four weeks to yield results.

Treatment

There is no specific medication that can cure hand-foot-and-mouth disease, as antibiotics are not effective against virus infections. Treatment is

intended to ease the pain and discomfort of the fever, mouth sores, and other symptoms of HFMD. To bring down the fever and relieve muscle pain, children can be given acetaminophen, ibuprofen, or another non-aspirin fever reducer or pain reliever. The doctor may recommend a mouthwash, throat lozenge, or throat spray that contains a mild anesthetic to relieve pain caused by blisters inside the mouth or throat. Another treatment that can help to ease throat pain is to gargle with a salt water rinse made by adding half teaspoon of salt to an 8-ounce glass of warm water.

It is important to make sure that the patient drinks plenty of fluids. Children with HFMD sometimes become dehydrated because the sores inside the mouth and throat hurt when the child tries to drink fruit juice, soft drinks, tea, or other drinks that contain acid. Milk-based drinks or cold foods like ice cream or popsicles are often less painful for the child to swallow. Children who do become dehydrated may need to be taken to the hospital for treatment with intravenous fluids.

Children with blisters on the hands and feet should keep the areas clean by washing gently with soap and water, then patting the skin dry to avoid breaking the blister and spreading the infection. If the blister does open, it should be covered with a small bandage.

Prognosis

Most people in any age group with HFMD recover completely in about a week. In a few cases, children have developed encephalitis, meningitis, or pneumonia; in rare cases, HFMD can cause death. An epidemic in Taiwan in 1998 that affected 1.5 million children resulted in 405 severe complications and seventy-eight deaths. An outbreak of HFMD in China that began in the spring of 2008 led to 25,000 reported cases and twenty-two deaths by early May.

Pregnant women who become infected with HFMD are at increased risk of losing the baby.

Prevention

There is no vaccine against HFMD. The most effective preventive measure is frequent and thorough hand washing, particularly after using the toilet, changing a diaper, before meals, and before preparing food. Another preventive measure is routinely cleaning shared toys in day care centers as well as in the home with a disinfectant, because the viruses that

cause HFMD can live on objects for several days. The Centers for Disease Control and Prevention (CDC) recommends washing toys (or soiled countertops and other surfaces) with soap and water, followed by using a solution of one tablespoon of chlorine bleach added to four cups of water.

Children with HFMD should stay home from child care or school until the fever has gone and the mouth sores and other blisters have healed. Adults with the disease should stay home from work.

The Future

Hand-foot-and-mouth disease is likely to continue to be a common infection because there are so many different enteroviruses that can cause it, and because these viruses are the second most common family of viruses—only the viruses that cause the common cold are more widespread.

Researchers are presently working on a rapid diagnostic test that would allow doctors to distinguish quickly between coxsackievirus A16 and enterovirus 71 in patients with symptoms of HFMD. Such a test would be helpful during epidemics because EV71 infections are more likely to lead to complications than coxsackievirus infections.

SEE ALSO Encephalitis; Meningitis; Pneumonia

For more information

BOOKS

Litin, Scott C., ed. Mayo Clinic Family Health Book. 3rd ed. New York: HarperResource, 2003.

PERIODICALS

Jacobs, Andrew. “Virus Kills 22 Children in Eastern China.” New York Times, May 3, 2008. Available online at http://www.nytimes.com/2008/05/03/world/asia/03china.html?_r=1&oref=slogin (accessed October 20, 2008).

WEB SITES

Centers for Disease Control and Prevention (CDC). Hand, Foot, and Mouth Disease (HFMD): Fast Facts. Available online at http://www.cdc.gov/ncidod/dvrd/revb/enterovirus/hfhf.htm (accessed October 20, 2008).

Mayo Clinic. Hand-Foot-and-Mouth Disease. Available online at http://www.mayoclinic.com/health/hand-foot-and-mouth-disease/DS00599 (accessed October 20, 2008).

Nemours Foundation. Hand, Foot, and Mouth Disease. Available online at http://www.kidshealth.org/parent/infections/bacterial_viral/hfm.html (accessed October 20, 2008).