Management of Erythema Infectiosum (Fifth Disease) in a 7-Year-Old Child
For a 7-year-old child with erythema infectiosum, provide symptomatic care only with antipyretics and antihistamines for pruritus, as the condition is self-limited and requires no specific antiviral therapy. 1
Clinical Recognition and Diagnosis
The diagnosis is primarily clinical, based on the characteristic three-stage rash evolution 1:
- Stage 1: "Slapped cheek" appearance—bright erythema on the malar eminences, sparing the circumoral area 1, 2
- Stage 2: Lacy, reticulated rash spreading to trunk, extremities, and buttocks within 1-4 days, more prominent on extensor surfaces with palms and soles typically spared 1
- Stage 3: Evanescence and recrudescence—the rash fades and recurs over 1-3 weeks, triggered by sunlight, heat, exercise, or stress 1
The prodrome consists of mild low-grade fever, headache, malaise, and myalgia occurring 4-14 days after exposure 1. Pruritus occurs in approximately 50% of cases 1.
Symptomatic Management
Provide supportive care only 1, 2:
- Acetaminophen or ibuprofen for fever and discomfort (dose according to weight-based pediatric guidelines) 1
- Oral antihistamines (diphenhydramine or cetirizine) for pruritus if present 1
- Reassure parents that the rash resolves spontaneously within 3 weeks without sequelae 1
- No antiviral therapy exists or is indicated 2
Critical Screening for High-Risk Complications
Immediately assess for underlying hemolytic disorders that place the child at risk for transient aplastic crisis 1, 2, 3:
- Sickle cell disease
- Hereditary spherocytosis
- Thalassemia
- Glucose-6-phosphate dehydrogenase deficiency
If any hemolytic disorder is present, obtain complete blood count with reticulocyte count to detect aplastic crisis (profound anemia with reticulocytopenia) 4, 1. Transient aplastic crisis represents a medical emergency requiring hospitalization and potential transfusion 1, 3.
Screen for immunocompromised status (HIV, chemotherapy, immunosuppressive therapy, congenital immunodeficiency), as these patients risk chronic anemia from persistent parvovirus B19 infection requiring intravenous immunoglobulin therapy 1, 2, 3.
Household Contact Screening
Identify pregnant household contacts immediately 4, 1:
- Parvovirus B19 infection in pregnancy carries 15% risk of fetal death at 13-20 weeks gestation and 6% risk after 20 weeks 4
- Pregnant contacts require urgent obstetric referral for serologic testing (IgM and IgG antibodies) 4
- Fetal hydrops from severe anemia may necessitate intrauterine transfusion 4, 1
Infection Control Precautions
By the time the rash appears, the child is no longer contagious 1, 2:
- Parvovirus B19 spreads via respiratory droplets during the prodromal phase (before rash onset) 1
- No isolation or school exclusion is required once the rash develops 1, 2
- The child may return to school immediately if feeling well 2
- Pregnant women and immunocompromised individuals should avoid contact only during the prodromal phase, which has typically passed by diagnosis 1
Common Pitfalls to Avoid
Do not confuse erythema infectiosum with other conditions 5:
- Scarlet fever: Has sandpaper-textured rash, strawberry tongue, and pharyngitis; requires antibiotic therapy 6
- Erythema multiforme: Shows target lesions with central dusky red papule/vesicle, pale zone, and erythematous halo; lesions remain fixed for minimum 7 days 5
- Drug reaction: Requires medication history; lacks the characteristic slapped-cheek appearance 5
Do not order serologic testing routinely, as diagnosis is clinical 1, 2. Reserve IgM/IgG antibody testing for pregnant contacts, immunocompromised patients, or those with hemolytic disorders where confirmation impacts management 1, 2.
Follow-Up Monitoring
Schedule return visit only if 1:
- Fever persists beyond 3-4 days
- Severe pallor, fatigue, or dyspnea develops (suggesting aplastic crisis)
- Joint pain or swelling occurs (arthralgia/arthritis affects 8% of children) 1
- Rash persists beyond 3 weeks