Hand foot and mouth disease
Hand foot and mouth disease is a common mild and short-lasting viral infection most often affecting young children; 95% are under 5 years of age. It is characterised by blisters on the hands, feet and in the mouth. The infection may rarely affect adults.
Hand foot and mouth disease is very infectious, so several members of the family or a school class may be affected. Epidemics are most common during the late summer or autumn months.
Hand foot and mouth disease is also called enteroviral vesicular stomatitis.
What is the cause of hand-foot-and-mouth disease?
Hand-foot-and-mouth is due to an enterovirus infection, usually Coxsackie virus (CV) A16, although it can also be due to Enterovirus 71 and other coxsackivirus types. One outbreak was reportedly due to Echovirus. Severe infections have most often been linked to Enterovirus 71. Mixed infections may occur. Recently, atypical hand-foot-and-mouth disease due to CVA6 has been reported.
What are its clinical features?
After an incubation period of 3 to 5 days, the viral infection results in mild fever, sore throat and loss of appetite. Malaise, swollen lymph glands, and mild diarrhoea may be present.
Flat pink patches on the dorsal and palmar surfaces of the hands and feet are soon followed by small elongated greyish blisters. These resolve by peeling off within a week, without leaving scars.
Usually there are also a few small oral vesicles and ulcers. These are sometimes painful, so the child eats little and frets. There may be a few on the skin around the mouth. In young children a red rash may develop on the buttocks and sometimes on the arms.
Atypical hand foot and mouth disease due to Coxsackie A6 results in a more widespread rash, larger blisters and subsequent skin peeling and/or nail shedding.
How is hand-foot-and-mouth disease diagnosed?
The diagnosis is typically made clinically, due to the characteristic appearance of blisters in typical sites, ie, hands, feet, and mouth.
In ill children, blood tests may be performed and may show:
- Raised white cell count
- Atypical lymphocytes
- Raised serum C-reactive protein (CRP)
- Positive serology for causative virus.
The causative virus may be isolated from swabs of vesicles, mucosal surfaces, or stool specimens, which confirms the infection but is rarely necessary.
Skin biopsy of a blister shows the characteristic histopathologic findings of hand-foot-and-mouth disease.
How is the infection transmitted?
The infection is passed on by direct contact with nasal and oral secretions or faecal contamination.
How is hand-foot-and-mouth disease treated?
Specific treatment is not necessary. The blisters should not be ruptured to reduce contagion.
Antiseptic mouth washes and simple analgesics such as paracetamol relieve the discomfort of eating.
No vaccines or specific antiviral medications are available.
Does the child have to stay off school?
As in the vast majority of cases hand foot and mouth disease is a mild illness, there is no need to keep children from school once they are well enough to attend.
However, the blisters remain infective until they have dried up, which is usually within a few days. The stools are infective for up to a month after the illness. Good hand-washing technique will reduce the spread of the disease.
Are there any complications from hand-foot-and-mouth disease?
CVA6 infections are often reported to cause nail changes including transverse lines across the nail plate, and sometimes complete loss of nails (onychomadesis) about 2 months after the illness. The line slowly moves outwards and eventually the nails return to normal.
Enteroviral infections may rarely cause more serious infection.
- Widespread vesicular rash
- Enteritis (gut infection)
- Myocarditis (heart muscle infection)
- Meningoencephalitis (brain infection)
- Acute flaccid paralysis (spinal cord infection)
- Pulmonary oedema and pneumonia (lung infection)
- In pregnancy, first tirmester spontaneous abortion or fetal growth retardation