Hand-foot-and-mouth disease (HFMD) is a common but highly contagious acute viral infection due to an enterovirus infection. The disease is most common under the age of 10, and most are under 5 years of age (95%). It can uncommonly affect adults and tends to be more severe in the elderly, immunocompromised, and pregnant women.  

What is the cause of hand, foot, and mouth disease?

Caused by Enterovirus usually Coxsackie virus (CV) A16. Other viruses causing HFM include:

 Enterovirus 71 (linked with severe infections that may involve the nervous system)

Coxsackievirus (CV) A5, A6, A7, A9, A10, B2, and B5

How is the infection transmitted?

Epidemics are most common during the late summer or autumn months. Hand foot and mouth is passed on by direct contact with the skin, nasal and oral secretions of infected individuals, or by faecal contamination.

What are the clinical features of hand, foot, and mouth disease?

The typical incubation period of HFMD is 3-5 days but has been known to range from, 2-7 days.

Symptoms usually include:

• Mild fever, malaise and loss of appetite.
• Lesions on the dorsal and palmar surfaces of the hands and feet. The progression is from flat pink patches to small, elongated greyish blisters, and, within a week, these peel off leaving no scars.
• Small vesicles and ulcers in and around the mouth, palate, and pharynx. These are sometimes painful, so the child eats little, frets, and may complain of a sore throat or mouth sores.
• Red rashes such as macules and papules on the buttocks and sometimes on the arms. Lesions can also occur on the genitalia.

Atypical hand foot and mouth disease results in a more widespread rash. Features may include:

• Widespread vesiculobullous lesions
• Eczema coxsackium with lesions concentrated in areas of eczematous skin
• Gianotti-Crosti type rash (multiple discrete, erythematous flat-topped papules symmetrically distributed on the face, buttocks, and extensor surface of the extremities)
• Purpuric lesions
• Onychomadesis (painless nail shedding) is common during convalescence

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 show:

• Raised white cell count
• Atypical lymphocytes
• Raised serum C-reactive protein (CRP)
• Positive serology for the causative virus, which 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 hand-foot-and-mouth disease treated?

Hand, foot, and mouth disease is a mild clinical syndrome and will resolve within 7 to 10 days. Treatment is primarily supportive and symptomatic. Specific treatment is not often necessary. 

• The blisters should not be ruptured, to reduce contagion.
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• Keep the blisters clean and apply non-adherent dressings to erosions.
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• Maintain adequate fluid intake; if oral intake is poor due to painful erosions, intravenous fluids may be indicated.
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• Antiseptic mouthwashes, topical and oral analgesics (Paracetamol) help relieve fever and pain due to oral ulcers.
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• Antihistamines can be given if itchiness present.

No vaccines or specific antiviral medications are available. Intravenous immunoglobulin and milrinone have shown some efficacy in a few reports.

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