Introduction

Hand, foot and Mouth disease (HFMD or HFM) is a common, self-limiting, viral infection that causes blisters on the hands, feet and inside/ around the mouth. It mainly affects children under 10 years of age with 95% of the cases occurring in toddler aged under 5 years. However, it can also affect older children/ adolescents. Adults, especially those who are immunocompromised, may also be affected.

It is also known as enteroviral vesicular stomatitis.

HFMD occurs sporadically worldwide. Epidemics are most common during warm weather, usually in the late summer or early autumn.

Outbreaks occur frequently among groups of children in childcare centres and schools.

Transmission

HFMD is usually caused by coxsackie A virus (A16 subtype) but may also be caused by other group A and group B coxsackie viruses and enterovirus 71. Transmission is mainly via direct contact with blister fluid or droplets spread from the mouth.

The incubation period is 3-6 days and children are usually infectious until blisters have ruptured and healed (around 7-10 days).

It tends to spread rapidly among family members or within schools. The virus can be shed in the faeces and saliva for several weeks.

Clinical features

HFMD usually begins with a prodrome of fever, sore throat, loss of appetite and lethargy.

The lesions usually appear 1-2 days following the fever. Many children remain well despite the rash.

The lesions are characterised by vesicular stomatitis (in the mouth) and cutaneous blisters at the distal extremities such as palms, fingers, toes, soles, and sometimes buttocks and genitals.

In children with pre-existing atopic dermatitis (eczema), the lesions may be localised in eczematous areas.

The lesions usually begin as small red spots that are often oval in shape, tender to touch and eventually blister. They usually peel off within a week, without leaving a scar.

Vesicles and ulcers in the mouth can be very painful. This will significantly impact the oral intake, especially in younger population such as infants and toddlers.

Diagnosis

HFMD is diagnosed clinically by its morphology, configuration and distribution of its lesions.

Cutaneous lesions are typically distributed symmetrically over the common sites such as hands, feet and around the mouth.

Other investigations such as polymerase chain reaction (PCR) testing, and skin biopsy of a vesicle are rarely indicated.

Treatment

Treatment of HFMD is mainly symptomatic management. HFMD rarely causes serious complications. Antibiotics are not indicated. There are no specific vaccines/ antiviral medication. General measures include:

• Simple analgesia such as oral paracetamol and ibuprofen can be used.
• Antiseptic mouthwash to topical soothing agents (such as lignocaine) can be used in children with painful oral vesicles/ ulcers. Hydration is very important in infants and toddlers.
•  Constantly offering sips of water/ juice can prevent dehydration. In cases with poor oral intake, nasogastric or intravenous fluid may be required.

Advice for Parents

Children with HFMD do not need be excluded from school. As the viruses spread through direct contact, hand hygiene is important to minimise transmission. Minimise sharing personal items such as cutlery, drinking cups, towel, toothbrushes and clothing can be beneficial within a family unit.

Complications

Severe complications are very uncommon in healthy children. Some rare complications that are associated with enteroviral infection include:

• Myocarditis
• Meningoencephalitis
• Acute flaccid paralysis
• Pulmonary oedema and pneumonia
• Haemorrhagic conjunctivitis
• Widespread blistering

Prognosis

A child will usually develop long term immunity to the specific virus that causes HFMD. However, a second episode can occur following infection with a different member of enterovirus group.

Written by Dr Stanley Leong,

Senior Paediatric Registrar and Dermatology Registrar

Edited by Dr Rebecca Evans Paediatrics ST3