Erythema infectiosum Dr Trisha Macnair This is an infectious disease that predominantly affects children. It's also known as fifth disease or 'slapped cheek syndrome' because of the typical rash that appears on the face.

In this article

What causes it? What are the symptoms?

Who's affected? How is it diagnosed?

What's the treatment?

Erythema infectiosum is caused by a virus called parvovirus B19. Outbreaks tend to occur in late winter or early spring, in cycles of every four to seven years.

The incubation period is usually four to 20 days and the virus is spread mainly through droplets in the air. It can also be transmitted through blood transfusions and from mother to unborn child.

In many cases the early symptoms are so mild they go unnoticed, but they may include a runny nose, headache, mild fever, sore throat and lethargy.

Some children also experience nausea, abdominal pain, diarrhoea and painful joints.

After a few days, a bright red rash may appear on the cheeks, but not on the nose or around the eyes or mouth.

After two to four days the rash, which looks a little like sunburn, usually disappears but another, non-itchy rash may appear on the extremities, including the palms and soles. This fades over a couple of weeks but may recur if the skin is exposed to heat, such as when in the bath, or physical stimuli such as friction.

Erythema infectiosum usually affects children between the ages of two and 14.

The symptoms, especially the typical rash on the face, are a good guide to the diagnosis. Blood tests can be used to confirm it, but are rarely necessary.

It needs no specific treatment, but paracetamol or ibuprofen may be used for fever and discomfort.

Most children suffer no long-term effects, but adults, pregnant women and children who are immunocompromised or have anaemia may develop more serious complications and should get medical advice.

This article was last medically reviewed by Dr Rob Hicks in February 2008