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Erythema Infectiosum (Parvovirus B19 Infection)

(Fifth Disease; Slapped-Cheek Disease)


Brenda L. Tesini

, MD, University of Rochester School of Medicine and Dentistry

Reviewed/Revised Jun 2023
Topic Resources

Erythema infectiosum is a contagious viral infection. In children, it causes a blotchy or raised red rash on areas of the body and a slapped-cheek red rash on the face along with mild illness. In a fetus, it may be fatal.

  • Erythema infectiosum is caused by a virus.

  • Symptoms include a mild fever, slapped-cheek red rash on the face, and a lacy rash on the arms, legs, and trunk.

  • The diagnosis is based on the characteristic rash.

  • Treatment is aimed at relieving symptoms.

Erythema infectiosum, often referred to as fifth disease, is caused by human parvovirus B19. The name "fifth disease" is used because it is considered the fifth in the list of viral infections that commonly cause rash in children. (The first four diseases are measles, scarlet fever, rubella, and scalded skin syndrome, and roseola is the sixth disease.) It is also sometimes called slapped-cheek disease.

Erythema infectiosum occurs most often during the spring months, often in geographically limited outbreaks among children, particularly school-aged children. The infection can occur in adults.

This infection is spread mainly by breathing in small droplets that have been breathed out by an infected person, so infection tends to spread within a household. Some people can be infected but have no symptoms. People are contagious from before the start of the rash until the rash appears.

Symptoms of Erythema Infectiosum

Erythema infectiosum symptoms begin about 4 to 14 days after infection. Many children have no symptoms. However, some children have a low fever and feel mildly ill with a headache and a runny nose for a few days.

Several days later, children develop red cheeks that often look like they have been slapped as well as a rash, especially on the arms, legs, and trunk but not usually on the palms or soles. The rash can be itchy and consists of raised, blotchy red areas and lacy patterns, particularly on areas of the arms not covered by clothing, because the rash may be worsened by exposure to sunlight.

The rash and the entire illness usually last 5 to 10 days. Over the next several weeks, the rash may temporarily reappear in response to sunlight, exercise, heat, fever, or emotional stress. In some adolescents and adults, mild joint pain and swelling may remain or come and go for weeks to months.

Diagnosis of Erythema Infectiosum

  • A doctor's evaluation

  • Sometimes blood tests

  • If infection occurs during pregnancy, ultrasonography of the fetus

A doctor bases the diagnosis of erythema infectiosum on the characteristic appearance of the rash.

Blood tests are done only in children who have a known blood disorder or an impaired immune system.

If infection occurs during pregnancy, blood tests are done in pregnant people to measure antibodies. The presence of certain antibodies tells doctors whether the pregnant person has been infected before or is currently or was recently infected. Pregnant people who may have been recently infected have an ultrasound to assess the fetus.

Treatment of Erythema Infectiosum

  • Relief of symptoms

Erythema infectiosum goes away on its own, so treatment is aimed at relieving the symptoms.

Children may be given nonsteroidal anti-inflammatory drugs (NSAIDs) to relieve fever, achiness, headache, and joint pain and other medications to relieve itching if it is severe.

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