Introduction

Parvovirus infection in children, also known as erythema infectiosum or "fifth disease," is a common viral illness caused by human parvovirus B19. It primarily affects children but can also occur in adults. The infection is generally mild and self-limiting, characterized by a distinctive "slapped cheek" rash and sometimes accompanied by flu-like symptoms.

Etiology

Human parvovirus B19, a small, non-enveloped DNA virus belonging to the Parvoviridae family, is the causative agent of erythema infectiosum. The virus targets erythroid progenitor cells in the bone marrow, leading to temporary suppression of erythropoiesis.

Epidemiology

• Prevalence: Parvovirus B19 infection is common worldwide, with seroprevalence increasing with age.
• Age distribution: Most cases occur in children aged 5-15 years.
• Seasonality: Outbreaks are more common in late winter to early spring.
• Transmission: Primarily through respiratory droplets and close personal contact.
• Incubation period: 4-14 days, but can be as long as 21 days.

Clinical Manifestations

The clinical presentation of parvovirus infection in children typically progresses through three stages:

1. Prodromal phase (2-3 days):
   • Low-grade fever
   • Malaise
   • Headache
   • Mild respiratory symptoms
2. Erythematous phase (7-10 days):
   • "Slapped cheek" appearance: bright red rash on the cheeks
   • Lace-like, erythematous rash on the trunk and extremities
   • Rash may be pruritic and can fluctuate in intensity
3. Recovery phase:
   • Gradual resolution of symptoms
   • Rash may recur with exposure to heat, sunlight, or stress

Note: Some children may be asymptomatic or experience only mild symptoms.

Diagnosis

Diagnosis of parvovirus infection in children is primarily clinical, based on the characteristic rash and associated symptoms. Laboratory tests can be used for confirmation:

• Serology:
  • IgM antibodies: indicate recent infection (detectable 7-10 days after exposure)
  • IgG antibodies: indicate past infection or immunity
• PCR: Detection of viral DNA in blood or tissue samples
• Complete blood count (CBC): May show transient anemia or reticulocytopenia

Treatment

Treatment for parvovirus infection in children is generally supportive, as the illness is usually self-limiting:

• Rest and adequate hydration
• Antipyretics and analgesics (e.g., acetaminophen) for fever and discomfort
• Antihistamines for pruritus, if necessary
• In severe cases or immunocompromised patients:
  • Intravenous immunoglobulin (IVIG) may be considered
  • Blood transfusions for severe anemia

Complications

While most cases of parvovirus infection in children are mild, complications can occur, especially in certain high-risk groups:

• Transient aplastic crisis: In patients with underlying hemolytic disorders (e.g., sickle cell disease, thalassemia)
• Chronic anemia: In immunocompromised patients
• Myocarditis: Rare but potentially severe
• Arthropathy: More common in adults but can occur in children
• Fetal complications: Hydrops fetalis and fetal loss in pregnant women infected during the first 20 weeks of gestation

Prevention

There is no vaccine available for parvovirus B19. Prevention measures include:

• Good hand hygiene
• Proper respiratory etiquette (covering mouth and nose when coughing or sneezing)
• Avoiding close contact with infected individuals
• Exclusion of symptomatic children from school or daycare until the rash appears (as they are no longer infectious at this stage)