Overview
- Erythema infectiosum: illness caused by parvovirus B19, associated with fever and a characteristic rash
- Epidemiology:
- Infection affects all ages but is more common in children between 3 and 15 years of age.
- Outbreaks occur commonly in schools and childcare settings.
- Occurrences of infection are more frequent in late winter and early summer.
- If a person is immunocompetent, immunity is usually conferred following infection.
Pathophysiology
Mode of transmission
- Respiratory secretions via:
- Saliva
- Mucus
- Fomites
- Contact with infected blood or blood products
- Vertical/transplacental transmission in nonimmune women (can result in congenital infection)
Incubation
The incubation period is 4–21 days.
Pathogenesis
- Initial B19 viral infection:
- Entry into the upper respiratory tract → viremia (prodromal symptoms) 5–10 days from exposure
- Virus spreads and is cytotoxic to rapidly dividing erythroid precursor cells in the bone marrow → transient ↓ reticulocytes and anemia
- In healthy individuals: Bone marrow effect is not clinically significant.
- In individuals with hematologic conditions: severe anemia/aplastic crisis occurs.
- In immunocompromised patients, viremic state can be prolonged.
- Rash:
- 2–5 days later, erythematous malar rash with circumoral pallor (“slapped cheek”) appears.
- Followed by lace-like erythematous rash on the trunk and extremities
- Rash appearance represents resolution of viremia (appearance of immunoglobulin M (IgM)) → no more constitutional symptoms
- May recur weeks later, triggered by sunlight, stress, or exercise
Clinical Presentation
Initial prodromal symptoms (viremia)
- Low-grade fever
- Headache
- Nausea
- Diarrhea
- Cold-like symptoms
- Pruritus
Later symptoms (viremia resolved)
- Days 2–5
- Rosy-red rash, mainly on cheeks
- Classic slapped-cheek appearance
- Rash extends over rim of the nose or mouth.
- Morbilliform → reticulated (lacey) rash:
- Upper arms
- Torso
- Legs
- Rash more common in children
Pediatric patient with fifth disease: erythematous facial rash accompanied by rash on the torso and extremities
Image: “Fifth disease” by Andrew Kerr. License: Public DomainErythema infectiosum: rash on the extremities
Image: “Fifth disease symptoms” by CDC. License: Public Domain
Complications
- Arthritis:
- Acute symmetric joint pain (hands, knees, ankles)
- More common in teenagers and adults (women > men)
- Up to 10% of children may have stiff joints.
- Can last 3 weeks or longer
- No degenerative joint changes
- Transient aplastic crisis:
- Rapid decline in RBCs
- Seen in patients with sickle cell disease, spherocytosis, and other hematologic diseases
- Patients present with weakness/lethargy and pallor.
- Maternal infection and fetal effects:
- Rare but a serious infection (leading to fetal RBC destruction), especially when onset is in the 1st 20 weeks of pregnancy
- Hydrops fetalis, miscarriage, intrauterine fetal death
- Chronic infection in immunocompromised patients:
- These patients cannot mount an immune response to viremia, increasing the risk for chronic infection.
- Results in pure red cell aplasia (giant pronormoblasts in the bone marrow) and severe anemia (reduced reticulocytes)
Transient aplastic crisis in parvovirus B19 infection
Image shows bone marrow cytology. Yellow arrow indicates a giant pronormoblast.
Diagnosis and Management
Diagnostic approach
- Diagnosis based on clinical features
- Additional test(s) in patients with signs and symptoms of anemia:
- Complete blood count (hemoglobin drops by 2 g/dL from baseline)
- Reticulocyte count decreased
- IgG and IgM antibody testing:
- For pregnant women
- Patients with hemoglobinopathies/hemolytic conditions
- Severe or persistent arthropathy
- Not utilized in immunocompromised patients, as they cannot produce detectable antibody levels
- In immunocompromised patients with pure red cell anemia: Polymerase chain reaction (PCR) for parvovirus B19 detects infection.
Treatment
- Generally, a self-limited illness and treatment is thus supportive.
- Severe transient aplastic crisis: Transfusion may be required.
- Immunocompromised patients with chronic infection and anemia may need:
- Reduced dose of immunosuppressive agents
- Intravenous immunoglobulin treatment
- In severe cases, bone marrow transplantation
Prevention
- General infection-control practices
- High-risk individuals should be informed of measures to avoid exposure and when to seek medical attention.
Differential Diagnosis
- Hydrops fetalis: serious fetal condition that involves an accumulation of fluid in 2 or more fetal compartments including ascites, pleural effusion, pericardial effusion, and skin edema. The condition carries a poor prognosis for perinatal survival.
- Aplastic crisis: occurs with significant reduced production of RBCs resulting in a rapid decline in the hemoglobin level with reticulocytopenia. With parvovirus B19 infection, the marrow function generally returns spontaneously within 1 week.
- Arthritis: joint disorder characterized by joint pain and stiffness accompanied by other manifestations such as redness, warmth, swelling, and decreased range of motion in joints.
Number | Other names for the disease | Etiology | Description |
---|---|---|---|
1st disease |
| Measles morbillivirus |
|
2nd disease |
| Streptococcus pyogenes |
|
3rd disease |
| Rubella virus |
|
4th disease |
| Due to Staphylococcus aureus strains that make epidermolytic (exfoliative) toxin |
|
5th disease | Erythema infectiosum | Erythrovirus or parvovirus B19 (Primate erythroparvovirus 1) |
|
6th disease |
| Human herpesvirus 6B or human herpesvirus 7 |
|
References
- Aqeel K.Z., & Turner A.R., & Mayeaux, Jr. E.J. (2019). Fifth disease. Usatine R.P., & Smith M.A., & Mayeaux, Jr. E.J., & Chumley H.S.(Eds.), The Color Atlas and Synopsis of Family Medicine, 3e. McGraw-Hill.
- Cennimo, D., Dieudonne, A. (2019). Parvovirus B19 infection. Medscape. Retrieved 24 Jan 2021 from https://emedicine.medscape.com/article/961063-overview
- Jordan, J. (2019). Clinical manifestations and diagnosis of parvovirus B19 infection. UpToDate. Retrieved 24 Jan 2021 from https://www.uptodate.com/contents/clinical-manifestations-and-diagnosis-of-parvovirus-b19-infection
- Jordan, J. (2020). Treatment and prevention of parvovirus B19 infection. UpToDate. Retrieved 24 Jan 2021 from https://www.uptodate.com/contents/treatment-and-prevention-of-parvovirus-b19-infection