Erythema infectiosum, also known as fifth disease, is a common infection of childhood. It is caused by a virus human parvovirus (PV) B19 and often characterized by a classic slapped-cheek appearance and lacy exanthem.

Symptoms in mild cases commonly appears approximately 1 week after exposure to PV-B19 and last 2-3 days.

Mild symptoms may include:

  • Headache
  • Fever
  • Pruritus
  • Coryza
  • Sore throat
  • Arthralgias
  • Abdominal pain

These symptoms precede a symptom-free period of about 7-10 days, after which the infection progresses through the following stages:

  • Phase 1 – The exanthem begins with the classic slapped-cheek appearance. It usually fades over 2-4 days.
  • Phase 2 – It occurs 1-4 days later and is characterized by an erythematous maculopapular rash that fades into a classic lacelike reticular pattern as confluent areas clear.
  • Phase 3 – Frequent clearing and recurrences for weeks or occasionally months may occur due to stimuli. It may include exercise, irritation, stress, or overheating of the skin from sunlight or bathing in hot water.


To diagnose erythema infectiosum, the doctor may base on clinical presentation alone. For patients with other signs or symptoms associated with human parvovirus (PV) B19 or for exposure in a woman who is pregnant, confirmation of infection may be accomplished with the following specialized tests:

  • IgM assays – Enzyme-linked immunosorbent assay (ELISA), radioimmunoassay (RIA)
  • Dot blot hybridization
  • Polymerase chain reaction (PCR) assay
  • Loop-mediated isothermal amplification



Mild cases usually go away on its own after a few days. Healthy children or adults often recover. Treatment of this infection usually relieves some of the symptoms including fever, itching, and joint pain and swelling.

People who have complications from fifth disease should see their doctor for medical treatment.

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