- Erythema infectiosum: illness caused by parvovirus B19, associated with fever and a characteristic rash
- 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.
Mode of transmission
- Respiratory secretions via:
- Contact with infected blood or blood products
- Vertical/transplacental transmission in nonimmune women (can result in congenital infection)
The incubation period is 4–21 days.
- 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.
- 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
Initial prodromal symptoms (viremia)
- Low-grade fever
- Cold-like symptoms
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
- Rash more common in children
- 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)
Diagnosis and Management
- 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.
- 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
- General infection-control practices
- High-risk individuals should be informed of measures to avoid exposure and when to seek medical attention.
- 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|
- 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