Hand Foot and Mouth Disease

The disease is caused by a group of enteroviruses. The most common is Coxsackie A16 but A5, A9, A10, B1-B3, and B5 as well as Enterovirus 71 can cause the illness.

• It occurs worldwide, with a peak incidence in the summer and autumn in temperate climates but no seasonal pattern in the tropics.
• Epidemics tend to occur every 3 years.
• There is no sex difference in incidence but boys are more likely to become symptomatically ill.
• It is most common among infants and children younger than 5 years.
• Clinical expression rate reduces with age from nearly 100% in preschool children to 40% in schoolchildren and 10% in adults.¹
• It tends to be a trivial illness. It is not notifiable and the HPA do not record numbers.

Symptoms

After an incubation period of 3 to 6 days there is a prodrome of low-grade fever, malaise and loss of appetite. The prodrome lasts 12 to 36 hours.

Signs

• After the prodrome lesions develop in the mouth and then on the skin. They are mainly on the hands and feet and occasionally on the buttocks.
• Lesions in the mouth are typically yellow ulcers surrounded by red halos.
• They are mainly on the palate, uvula, buccal mucosa, tongue, with the gums and lips sometimes involved.
• They are uncomfortable rather than painful. Children under 5 years have worse symptoms than older children.
• The skin lesions are on the palms, soles, and between the fingers and toes. They may itch.
• They start as erythematous macules but rapidly progress to grey vesicles with an erythematous base.
• In young infants, they may be on the trunk, thighs, and buttocks. These lesions are mainly an erythematous maculopapular rash rather than the papulovesicular ones found on the hands and feet.
• The rash lasts about 3 to 6 days.

• Herpangina. It is caused by similar coxsackie or echo viruses with lesions similar to hand, foot and mouth disease, but limited to the posterior oral cavity. (Angina come from the Greek word ankhone meaning "a strangling" and does not imply a cardiac cause).
• Herpes Simplex.
• Chickenpox.
• Measles.

The virus can be cultured from the lesions or detected serologically, but usually no investigation is merited.

If it occurs in immunocompromised patients it is more serious but it does respond to acyclovir.²

Non-Drug

• If the mouth is uncomfortable, dehydration may result from poor fluid intake but admission to hospital is rarely required.
• Parents are often shocked by the name of the disease so they need to be assured that it is unrelated to foot and mouth disease of animals and the child will not have to be "put down".

Drugs

• Antipyretic analgesics such as paracetamol or ibuprofen are usually all that is required.
• If the mouth is very painful, an analgesic such as benzydamine may be helpful.
• Antibiotics are only required if secondary infection of skin lesions occurs.

• Complications are rare, but the commonest is secondary infection of skin that has been scratched.
• If infection occurs in the first trimester of pregnancy it may result in spontaneous abortion or intrauterine growth retardation.³
• Enteroviruses can cause viral meningitis but this disease is usually not associated with meningitis.
• Cardiovascular and neurological complications are rare.⁴ They are myocarditis causing heart failure and pulmonary oedema, pneumonia, paralytic disorder and meningo-encephalitis. A very unusual outbreak in Sarawak in 1997 left 26 previously healthy children dead⁵ but usually the disease is benign. The children seemed to die of cardiogenic shock but there was no postmortem evidence of myocarditis.⁶ Encephalitis was found.

There is usually uneventful recovery.

Attention to hand washing in the family should reduce further spread. The virus may be excreted in the faeces for months. Exclusion from school is probably of no value as the virus has been excreted for weeks.⁷