What is fifth disease?

Fifth disease (also known as ‘slapped cheek disease’, erythema infectiosum or Parvovirus B19) is a fairly mild viral illness, usually of childhood. It is a common infection — half of adults have been infected during their childhood.

Why is it called fifth disease?

It is called fifth disease as it was the fifth of the 5 common viral rash illnesses of childhood.

The ‘slapped cheek disease’ name comes from its most obvious symptom — a red rash that makes children’s cheeks look like they’ve been slapped.

What are the symptoms of fifth disease?

In children, the symptoms of fifth disease are often mild and you may not notice them in your child. The symptoms in a child may include a mild fever, headache and cold symptoms, such as a runny nose.

A few days later, a bright red rash, like the mark left by a slap, appears on the cheeks. Over the next 2 – 4 days a pink lacy rash appears on the trunk and limbs. This may be itchy. The rash usually clears up in 7 – 10 days.

Some children may experience the body rash coming and going for a few weeks — generally brought on by heat or sunlight.

Children may get joint pain as a symptom, although this is not common in children.

Children with blood disorders such as spherocytosis or sickle cell disease may become more anaemic. They should seek medical care.

Adults with fifth disease may not have any symptoms at all, or they may have joint pain and stiffness, but they don’t usually get the slapped cheek rash. The joint pain can take 1 – 2 weeks to go away. Sometimes it lasts longer, even months or years.

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What causes fifth disease?

Fifth disease or slapped cheek disease is a viral infection caused by human parvovirus B19. Outbreaks generally happen in winter and spring. The virus is spread through contact with infected respiratory secretions, such as through coughing and sneezing. It may also be passed from mother to unborn baby.

Once a person has been infected they will generally be immune to the disease.

When should I see my doctor?

Certain people should contact their doctor immediately, if they think they have been in contact or may be infected with human parvovirus, including:

• pregnant women
• anyone who is immunosuppressed
• anyone with haemolytic anaemia

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How long is someone with fifth disease infectious?

The infectious period is a few days before the rash appears (children are no longer contagious when the rash appears).

Children are not excluded from school or child care, but they should stay at home if they have a fever, and until they feel well.

Fifth disease will infect around half of all previously uninfected household contacts and up to 60% of school or childcare contacts.

What is the incubation period for fifth disease?

The incubation period for fifth disease varies from 4 to 20 days. This is the time between a person being infected and them developing symptoms.

How is fifth disease diagnosed?

Fifth disease can often be diagnosed by the presence of the characteristic rash, during a physical examination.

Blood tests are usually only done if a person is at risk of complications. The blood tests can detect antibodies to fifth disease, which show previous exposure to the parvovirus, or the genetic material of the virus, showing an active infection.

Amniotic fluid may be tested in a pregnant woman if the fetus is affected by hydrops fetalis (fluid accumulation).

What is the treatment for fifth disease?

Fifth disease is caused by a virus (parvovirus) so antibiotics will not be effective. Treatment is aimed at managing the symptoms, which can usually be done at home.

If your child is infected:

• make sure they rest and drink plenty of fluids
• give them paracetamol or ibuprofen, if necessary, to relieve the discomfort and fever

Adults with fifth disease may need to rest, or take ibuprofen if they have joint pain. Your doctor or pharmacist will be able to advise if ibuprofen is suitable for you.

Can fifth disease be prevented?

No vaccine is currently available for fifth disease. It helps to follow good hygiene and careful handwashing, especially in childcare facilities and schools, but there’s nothing else you can do to stop it spreading.

Parvovirus is most contagious during the incubation period, before your child develops the rash or other symptoms. Your child isn’t usually contagious once the rash has appeared and fifth disease is diagnosed, so there’s then no need to keep your child home from childcare or school.

What if I get fifth disease while pregnant?

Pregnant women or women planning to become pregnant should see their doctor or midwife as soon as possible if they come into contact with the infection or develop a rash. Parvovirus can affect the unborn baby, though this is rare.

Half of all women will have had fifth disease previously, and so will be immune to parvovirus. If a pregnant woman who isn’t immune gets fifth disease, usually the illness is mild and doesn’t affect the baby. But rarely, an unborn baby can develop anaemia or fluid accumulation (hydrops fetalis) if the mother gets parvovirus. This can lead to miscarriage.

Are there any complication of fifth disease?

As mentioned, the rash may return in children for a couple of weeks. Adults may have joint pain which lasts for days, weeks or months after infection.

As parvovirus affects the development of red blood cells, certain groups of people are more at risk of complications, including:

• women in the first half of pregnancy — the fetus may develop anaemia or fluid accumulation (hydrops fetalis), which sometimes leads to miscarriage
• anyone who is immunosuppressed — chronic (ongoing) anaemia may result and be difficult to treat
• anyone with haemolytic anaemia — they may develop severe anaemia during the infection