Family doctor

What is it?

This is an infection causing a rash and mild illness mostly in children. It rarely affects babies. It was called fifth disease because in the pre-immunisation days it was described as being one of the five most common childhood infections.

It is caused by a virus known as parvovirus B19 (first discovered in1975). Therefore treatments such as antibiotics are of no help. This is a human parvovirus not the same as the dog or cat parvoviruses. There is no specific treatment. It is thought that once a child has had the disease there is lifelong immunity. There is no vaccination against it.

The main worry with the parvovirus B19 infection is that it can occasionally cause intrauterine death in pregnancy especially in the first half. This is a rare cause of intrauterine death. However prevention is a problem because children are infectious before the symptoms come out. However studies have shown that 50% to 70% of adults have immunity to parvovirus B19 from childhood infection, often without getting the symptoms.

Parvovirus B19 disease can occur in epidemics which may present a problem for pregnant women who work with groups of children.

The incubation period is 7 to 28 days - average 16 days. The child is infectious for 5 to 6 days before the rash appears and is no longer infectious to others once the rash comes out. The virus is thought to be transmitted through respiratory secretions but can also be transmitted through blood.

What are the symptoms?

A rash is the main sign of infection. The rash usually appears in 3 stages:

(a) The "slapped cheek rash" comes first. The cheeks have a flushed appearance as though the child has been slapped.

(b) Then a red blotchy rash appears on the body and arms and legs. Only occasionally does it appear on the palms and soles.

(c) Then this rash can fade to become a lace-like pattern and the whole rash sequence can last up to 40 days but the average is 11 days. The rash can seem to fade and then flare-up when the child is hot or after exercise or emotional upset. It is often itchy.

The child can have a mild generalised upset such as sore throat, fever and headache, cold like symptoms and tummy upset with diarrhoea, and this usually occurs a few days before the flushed cheeks or body rash appears.

It is important to see a doctor for any unwell child with a rash as other more serious conditions (e.g. meningitis) may cause similar symptoms.

What can be done?

No specific treatment is available and if the child feels well enough it is NOT necessary to keep the child away from school or pre-school. Rest and plenty of fluids are advised for children who feel unwell.

Complications are rare in healthy children but the disease can be a problem for children with immune deficiency or sickle cell anaemia or haemolytic anaemia. Parvovirus B19 affects the production of red blood cells. Adults rarely get parvovirus B19 infection but if they do the rash can be itchy and sore joints can be a feature.