Erythema infectiosum (also known as fifth disease or 'slapped-cheek syndrome') is caused by parvovirus B19.


  • Incidence: 40.00 cases per 100,000 person-years
  • Peak incidence: 6-15 years
  • Sex ratio: 1:1
<1 1-5 6+ 16+ 30+ 40+ 50+ 60+ 70+ 80+

Clinical features

The illness may consist of a mild feverish illness which is hardly noticeable. However, in others there is a noticeable rash which appears after a few days. The rose-red rash makes the cheeks appear bright red, hence the name ‘slapped cheek syndrome’. The rash may spread to the rest of the body but unlike many other rashes, it only rarely involves the palms and soles.

The child begins to feel better as the rash appears and the rash usually peaks after a week and then fades. The rash is unusual in that for some months afterwards, a warm bath, sunlight, heat or fever will trigger a recurrence of the bright red cheeks and the rash itself.


Most children recover and need no specific treatment.

The child need not be excluded from school as they are no longer infectious by the time the rash occurs.

In adults, the virus may cause acute arthritis.


Be aware that the virus can affect an unborn baby in the first 20 weeks of pregnancy. If a woman is exposed early in pregnancy (before 20 weeks) she should seek prompt advice from whoever is giving her antenatal care.
It is spread by the respiratory route and a person is infectious 3 to 5 days before the appearance of the rash. Children are no longer infectious once the rash appears and there is no specific treatment.