Fifth Disease (Parvovirus B19): The Slapped-Cheek Infection

Fifth disease, also called erythema infectiosum, is a viral infection caused by parvovirus B19. This virus infects only people — it isn't the parvovirus that dogs and cats get. Fifth disease mostly affects children and often causes a bright red rash on the cheeks, sometimes called a "slapped cheek" rash.

In the United States, parvovirus B19 infections are most common in late winter, spring and early summer, and small outbreaks usually occur about every 3 to 4 years.

How it spreads

The virus passes from person to person:

• through respiratory droplets — saliva, sputum or nasal mucus — when an infected person coughs or sneezes, or when you touch something contaminated;
• through blood or blood products;
• from a pregnant parent to the baby.

People are most contagious early on, when they usually have only a fever or cold-like symptoms, and are unlikely to be contagious once the rash and joint pain appear.

Symptoms

About 2 in 10 people infected have no symptoms. Most get mild symptoms, which can include fever, headache, cough, sore throat, rashes and joint pain.

• Children are more likely to get the "slapped cheek" rash, usually a few days after the first symptoms. It can then spread to the arms, legs, chest, back and buttocks.
• Adults may also get joint pain and swelling (polyarthropathy syndrome).

Sometimes the infection causes serious complications affecting the nerves, joints or blood. These are more likely during pregnancy, with a blood disorder such as anemia, or with a weakened immune system. Because of the risks to you and possibly your baby, if you are pregnant, contact your health care provider if you have signs of fifth disease or may have been exposed to someone who has it.

Diagnosis

There is no routine lab test for fifth disease; providers can often diagnose it from the rash. A test can show whether you are immune to parvovirus B19 or were recently infected. It usually isn't needed, but may be ordered during pregnancy or if you are at higher risk of complications.

Treatment

There is no specific treatment. Fifth disease is usually mild and goes away on its own. Rest, and take acetaminophen for fever and pain. Don't give aspirin to children — it can cause Reye syndrome, a rare, serious illness that can affect the brain and liver.

Prevention

There is no vaccine. You can protect yourself and others by:

• washing your hands often with soap and water;
• covering your mouth and nose when you cough or sneeze;
• not touching your eyes, nose and mouth with unwashed hands;
• avoiding close contact with people who are sick;
• staying home when you are sick.

Most people are immune after they've had it once.

Sources

• MedlinePlus (U.S. National Library of Medicine): "Fifth Disease," with information from the Centers for Disease Control and Prevention.