(Fifth disease - Parvovirus B19)
Slapped cheek syndrome is caused by an infection with a virus known as human parvovirus B19. It is usually a mild self-limiting disease, occurring in small outbreaks among children, particularly in winter and spring. Small outbreaks are common in schools and usually reflect increased circulation of the virus in the wider community. A red rash appears on the face giving a ‘slapped cheek’ appearance and may also involve the legs and trunk. Often the child may have a runny nose and cough. Some people, mainly adults, can develop mild joint pains. There is no specific treatment.
Cases are infectious for approximately 7 days before the rash appears and are usually no longer infectious when the rash has appeared. Anyone who is not immune can be infected, but the disease seems to occur more often in the 5 to 14 year age group. By the age of 20 to 25 years, more than half of all adults have been infected and have developed life-long immunity. Infection is spread by respiratory secretions (e.g. saliva, sputum, nasal mucus) through sneezing, coughing or direct contact with these secretions. In people with chronic red blood cell disorders (e.g. sicklecell disease or spherocytosis) or whose immune system is significantly weakened, infection may result in severe anaemia requiring treatment.
Most pregnant women, especially women who work with children, are already immune to parvovirus and therefore do not become infected. For women who are not immune a small number may become infected. Infection is more likely after contact with an infectious person in a household setting rather than an occupational (school) setting. For the small number of women who develop infection, the infection may pass to the foetus. In most instances infection in the foetus does not lead to any adverse effects. In a very small number of cases infection in the foetus before the pregnancy has reached 21 weeks may cause anaemia which may need treatment. There is also a rare association between infection in the foetus in early pregnancy and miscarriage.
Preventive measures include strict hand washing especially after contact with respiratory secretions (e.g. saliva, sputum, nasal mucus). People, especially pregnant women or those with chronic red blood cell disorders or impaired immunity, with sick children at home should wash hands frequently and avoid sharing eating/drinking utensils. Pregnant women, those with chronic red blood cell disorders (e.g. sickle cell disease) and those with impaired immunity should seek medical advice if they believe they have been in contact with a case either at home, in the community or at work.
An affected staff member or pupil need not be excluded because he/she is no longer infectious by the time the rash occurs. Circulation of parvovirus in schools reflects circulation of the infection in the wider community. In addition by the time someone develops the typical rash of slapped cheek syndrome they are usually no longer infectious and their contacts have already been exposed. Excluding pregnant teachers from school will not prevent them from being exposed to infection and therefore exclusion is not recommended as a public health measure to protect pregnant women from infection.
Useful information on slapped cheek syndrome can be found at http://www.hpsc.ie/a-z/other/parvovirus.