Fifth Disease
A mild viral illness with a "slapped cheek" rash, caused by parvovirus B19
Quick Facts
- Type: Viral infection
- Cause: Parvovirus B19
- Who it affects: Most common in school-age children
- Hallmark: Bright red "slapped cheek" rash
Overview
Fifth disease, also called erythema infectiosum, is a common and usually mild viral illness caused by parvovirus B19. It earned its name because it was historically the fifth in a list of common childhood rash-causing illnesses.
It is best known for the bright red rash on the cheeks that looks as if the child has been slapped, often followed by a lacy rash on the body. Most children recover fully without treatment. However, the infection can be more serious for certain groups, including pregnant women and people with some blood disorders or weakened immune systems, who may need closer attention.
Symptoms
Symptoms appear in stages. Early, flu-like symptoms come first, followed by the characteristic rash several days later.
- Mild fever, runny nose, and headache early on
- Tiredness and a general feeling of being unwell
- A bright red rash on both cheeks (the "slapped cheek" appearance)
- A lacy, pink rash that spreads to the arms, trunk, and legs
- Mild itching of the rash
- Joint pain and swelling, more common in adults
The body rash may come and go for a week or two and can become more noticeable with heat, sunlight, or exercise. By the time the rash appears, the person is usually no longer contagious.
Causes
Fifth disease is caused by parvovirus B19, a virus that infects only humans. It spreads mainly through respiratory droplets from coughing and sneezing, and through contact with respiratory secretions. It can also pass from a pregnant woman to her baby and, less commonly, through blood.
A person is most contagious in the early phase before the rash appears, during the flu-like symptoms. Once the rash shows up, the infection has usually passed its contagious stage, which is why children with the rash are generally allowed to return to school.
Risk Factors
- Being a school-age child, the most commonly affected group
- Close contact with infected children at home, school, or childcare
- Working in schools or childcare settings
- Outbreaks in the community, which are more common in late winter and spring
Once a person has had fifth disease, they usually develop lifelong immunity and do not get it again.
Diagnosis
Fifth disease is usually diagnosed by recognizing the typical rash and symptoms, so testing is often unnecessary.
- Clinical examination: The slapped-cheek rash followed by a lacy body rash is often enough to make the diagnosis.
- Blood tests: May be used to confirm parvovirus B19 in pregnant women, people with weakened immune systems, or those with certain blood disorders, where confirmation matters.
Treatment
There is no specific cure, and most cases need only supportive care while the body clears the virus.
- Rest and fluids: To support recovery.
- Fever and pain relief: Acetaminophen or ibuprofen as directed for the person's age; aspirin should not be given to children.
- Itch relief: Soothing measures for any mild itching.
- Special monitoring: People with certain blood disorders or weakened immunity may need closer follow-up or specific treatment, as the virus can affect red blood cell production.
Most people feel better within one to two weeks, though the rash and joint aches can linger a little longer in some.
Prevention
- Wash hands frequently and thoroughly
- Cover coughs and sneezes
- Avoid sharing cups and utensils
- Stay home when feeling unwell with flu-like symptoms
There is no vaccine for fifth disease. Because people are most contagious before the rash appears, it can be hard to prevent spread, so good hygiene is the main defense.
When to See a Doctor
See a doctor if you are pregnant and have been exposed to fifth disease or develop a rash, as the infection can affect a developing baby and needs monitoring. Also seek care if you have a blood disorder such as sickle cell disease or a weakened immune system, since the virus can cause a serious drop in red blood cells.
Contact a doctor if a child becomes very pale, unusually tired or short of breath, or has a high or persistent fever, severe joint pain, or any symptoms that worry you.
Frequently Asked Questions
Is fifth disease contagious?
Yes, but it spreads mainly during the early flu-like phase before the rash appears. Once the slapped-cheek rash shows up, the person is usually no longer contagious, which is why children with the rash can typically return to school.
Is fifth disease dangerous during pregnancy?
It is usually mild, but the infection can occasionally affect a developing baby. If you are pregnant and have been exposed or develop a rash, contact your doctor so the pregnancy can be monitored as needed.
How long does the rash last?
The slapped-cheek rash usually fades within a few days, while the lacy body rash can come and go for one to three weeks. It may become more noticeable with heat, sunlight, or exercise during this time.
Can adults get fifth disease?
Yes. Adults can get it, often with milder respiratory symptoms but more noticeable joint pain and swelling than children. Once you have had the infection, you usually develop lifelong immunity.
Who needs to be especially careful with fifth disease?
Pregnant women, people with blood disorders such as sickle cell disease, and those with weakened immune systems should be cautious, because the virus can affect red blood cell production. These groups should contact a doctor if exposed or symptomatic.
References
- Centers for Disease Control and Prevention (CDC). Fifth disease (parvovirus B19).
- American Academy of Pediatrics.
- Mayo Clinic. Parvovirus infection — Symptoms and causes.
- MedlinePlus, U.S. National Library of Medicine. Fifth disease.