Slapped cheek syndrome is a viral infection affecting children aged between 3 and 15 years. Infection with parvovirus B19 causes the condition. This virus is an airborne virus transmitted in much the same way as the cold or flu virus, through inhalation of infected droplets suspended in the atmosphere as a result of infected individuals sneezing or coughing. After inhaling the virus, a child usually takes around a week or two to manifest symptoms.

Symptoms

Symptoms of slapped cheek syndrome may occur as follows:

• The first stage of infection causes mild flu-like features, with a fever that peaks at around 38.5C, runny nose, headache, sore throat, itchy skin, diarrhea and fatigue. This phase of infection is highly contagious and the child may pass on the infection to other children they come into contact with. Due to the mild nature or complete absence of symptoms, the infection is seldom detected at this stage.
• The second stage of the infection occurs around a week after the first stage begins. This phase is typically characterized by the distinct bright red rash across the cheeks, so typical of the condition. The rash is particularly prominent when viewed in sunlight.
• The third stage begins around three to four days after the cheek rash manifests. During this stage, the rash commonly spreads to the child's neck, chest, back, abdomen, legs and arms. The rash appears red and lacy and is more prominent on exposure to heat or after exercise. The rash usually passes away within a week after it appears but can take a few weeks to disappear in some individuals. At this stage, the child is no longer contagious and may attend school.

Parvovirus B19 in adults

In adults, parvovirus B19 infection leads to joint pain and stiffness. especially in the knees, wrists, fingers and ankles. There may rarely be other symptoms such as fever, weakness, headache and sore throat. The symptoms usually pass within a couple of weeks but may last longer, leading to residual joint pain and stiffness.

Persons at high risk of more severe complications include pregnant women who may miscarry if the infection causes severe anaemia in the foetus, elderly individuals with low immunity in whom symptoms may be more severe or prolonged, and people with blood disorders such as sickle cell anaemia, thalassaemia and spherocytosisin in whom anaemia may, again, be more dangerous. In addition symptoms may be more serious in people with weakened immune system such as individuals positive for HIV or those undergoing chemotherapy or taking steroids.