A nine-year-old was brought to the morning surgery by her anxious mother. The child had been slightly ‘off colour’, with a slight cold for a few days. That morning she was found to have highly coloured red cheeks.
The mother had recently found out that she was about 12 weeks pregnant.
A diagnosis of fifth (or slapped cheek) disease was made. The mother was reassured it was a mild viral infection that would clear without specific treatment and very rarely led to complications. She was told that an erythematous, macular type of rash might develop on the trunk and limbs and subsequently fade to a lacy pattern, clearing spontaneously within a few days.
In general, there is no specific treatment, but analgesics such as paracetamol or ibuprofen, plenty of fluids and rest may be helpful.
As the mother was pregnant, she was asked to reattend for further discussion and advice about possible effects on the pregnancy.
Fifth disease is caused by parvovirus B and although it may occur at any age, is commonly seen in children between the ages of three and 15 years, in late winter or early spring. By the age of 20, 60% are seropositive to the virus and have life-long immunity.
The prodromal phase of the illness – malaise, coryza and low-grade fever – often passes unnoticed, so the first sign is frequently that of the typical erythematous, red cheeks. There follows an erythematous macular rash, mainly of the extensor surfaces of the limbs, palms and soles. Within a few days, this fades to a paler, lacy pattern, which may be exacerbated by the sun, heat or exercise; this clears after a few weeks.
The disease is spread by droplets among close contacts and the incubation period ranges from four to 14 days. Isolation of cases is difficult because the infectious period is during the prodromal phase, at which time the condition is unlikely to be recognised.
Fifth disease is not notifiable and school exclusion is not recommended, provided the child is well enough to attend. Complications are few but there are particular risks for the non-immune who contract the disease in pregnancy: fetal damage with anaemia; miscarriage, if it occurs in the first 20 weeks of pregnancy (9% risk); hydrops fetalis, if the infection occurs between nine and 20 weeks (3% risk); or stillbirth.
If infection is suspected, it should be confirmed by parvovirus serology and if positive, followed up by regular ultrasound check of fetal growth and development. In a case of hydrops fetalis, an intrauterine infusion may be indicated.
For those with haemoglobinopathies such as sickle cell, beta thalassaemia or hereditary spherocytosis, or those who are immunocompromised, there are greater risks of acute arthritis, aplastic crisis and bone marrow failure.
Possible differential diagnoses
- Scarlet fever
- Roseola infantum
- Drug eruptions