Basics
Description
- Characteristic viral exanthem also known as 5th disease:
- 5th most common childhood rash historically described
- Measles (1st), scarlet fever (2nd), rubella (3rd), Duke disease (4th), roseola (6th)
- Common symptoms: Viral prodrome followed by slapped-cheek rash and subsequent diffuse reticular rash +/- arthropathy
- Most common in school-aged children <14 yr
- Usually self-limited with lasting immunity
- Rare complications and chronic cases in patients with congenital anemias or immunosuppression
- Potential for severe complications to fetus if infection acquired during pregnancy
- Possible link to encephalopathy, epilepsy, meningitis, myocarditis, dilated cardiomyopathy, autoimmune hepatitis, HSP, ITP
Etiology
- Caused by human parvovirus B19, small SS-DNA virus:
- Infects human erythroid progenitor cells, suppressing erythropoiesis
- Most common in late winter and spring
- Transmitted via respiratory droplets and blood products as well as vertical maternal-fetal transmission
- Incubation period 4-21 days
- Most contagious during the week PRIOR to rash onset
- Majority of adults have serologic evidence of prior infection
Diagnosis
Signs and Symptoms
- "Slapped-cheek" appearance most common in young children
- Fever
- Malaise
- Delayed symptoms 4-14 days later:
- Diffuse, pruritic, lacy rash (absent in most adults), most pronounced in extremities
- Symmetric polyarthropathy, most common in middle-aged women:
- Small joints involved in adolescents and adults
- Knees most commonly involved in children
- Secondary to immune-complex deposition
- However, most patients remain asymptomatic or only develop mild, nonspecific viral symptoms
History
- Mild constitutional symptoms (fever, headache, nasal congestion, nausea, sore throat)
- Contagious only until facial rash appears
Physical Exam
- Stage 1:
- "Slapped-cheek" rash of coalescent, warm, erythematous, edematous papules with circumoral pallor in young children
- Stage 2:
- Nonspecific, diffuse, pruritic, maculopapular, reticular eruption
- 4-21 days after facial rash, lasts up to 6 wk
- More prominent on extremities
- Usually spares palms and soles
- Stage 3:
- Rash fades but recurs with exposure to sunlight, stress, exercise, and heat
- Usually complete resolution without scarring
Essential Workup
Clinical diagnosis based on characteristic signs and symptoms.
Diagnosis Tests & Interpretation
- Usually not necessary
- CBC and reticulocyte count if concern for aplastic crisis
- Confirm diagnosis if immunocompromised or pregnant:
- Viral DNA PCR now available
- IgM antibody confirms acute infection and persists for 2-3 mo
- IgG presence confers lasting immunity
- In pregnancy, ultrasound to detect hydrops fetalis
Differential Diagnosis
- Allergic reaction
- Collagen vascular disease
- Coxsackie virus
- Drug eruptions
- Enterovirus
- Erysipelas
- Infectious mononucleosis
- Measles
- Nonspecific viral illness
- Rheumatoid arthritis
- Roseola
- Rubella
- Scarlet fever
- Sunburn
Treatment
Erythema infectiosum is usually self-limited and does not require treatment
Pre-Hospital
ABCs for severe cases and septic patients
Initial Stabilization/Therapy
- ABCs, supplemental oxygen if indicated
- IVF with associated severe dehydration
- Severe anemia may also cause hypotension and hypoxia, transfuse PRBCs as indicated
- Pain control with acetaminophen, NSAIDs, or opiates as needed for severe arthropathy
Ed Treatment/Procedures
- No specific antiviral treatment or vaccine is available
- Send appropriate labs (CBC, reticulocytes, antibody testing) for severe cases
- Symptomatic treatment as needed:
- IVF for severe dehydration
- NSAIDs for arthropathy if no underlying renal insufficiency
- Consider diphenhydramine for pruritus, caution parents about possible AMS
- Antipyretics for fever
- PRBC transfusion for severe anemia
- ID consult: IVIG may have benefit for immunocompromised patients with chronic symptoms and red cell aplasia
- Hematology consult for severe cases
- Hospitalization and respiratory isolation for aplastic crisis
Medication
- Acetaminophen: 500 mg (peds: 15 mg/kg/dose) PO q6h PRN fever for up to 5 days
- Dose not to exceed 4 g/24h
- Diphenhydramine: 25 mg (peds: 1-2 mg/kg/dose) PO q6h PRN itching for up to 5 days
- Ibuprofen: 400 mg (peds: 10 mg/kg/dose) PO q8h PRN pain for up to 5 days
- IVIG only in consultation with ID specialist
Follow-Up
Disposition
Admission Criteria
- Aplastic crisis or severe anemia
- Severely immunocompromised
- Hydrops fetalis
- Toxic appearance
- Severe arthritis
Discharge Criteria
- Nearly all patients
- Normal CBC, O2 sat, and BP
- Patients are no longer contagious following appearance of facial rash and may return to day care, school, or work
Issues for Referral
- All patients without existing primary care physicians should be referred to a generalist for follow-up as needed
- Patients with hereditary anemias should be referred to hematology for follow-up in 1-2 days
- All immunocompromised patients require prompt subspecialty follow-up
- Pregnant patients with new infection should have immediate follow-up with OB/GYN for further monitoring and ultrasound
Follow-Up Recommendations
- Pregnant women with new parvovirus B19 infection may need serial ultrasounds for 10-12 wk.
- Patients at risk for aplastic crisis should follow-up with the appropriate specialties 1-2 days after ED discharge for repeat CBC
Patient Education
Prevention:
- No vaccine available
- Frequent handwashing helps prevent spread
- No current recommendations to keep children out of school, since most children are no longer contagious by the time the diagnosis is made.
- Pregnant women may choose to stay away from a workplace outbreak, but no current official recommendation exists
Complications
- Transient aplastic crisis in patients with anemias: Sickle cell disease, hereditary spherocytosis, thalassemia, iron-deficiency, or other conditions with shortened red cell lifespan:
- Usually full recovery within 2 wk
- Persistent infection with severe anemia if immunocompromised and unable to mount antibody response, especially with HIV
- Arthritis or hypersensitivity dermatitis in adults:
- May have transient rheumatoid factor positivity, but no true association with rheumatoid arthritis and no joint destruction
- Association with papular, purpuric gloves, and socks syndrome in adults:
- Symmetric, painful progressive rash and edema of hands and feet
- Erythema progresses to petechiae, purpura, and occasionally bullae
- This syndrome is also associated with many other viruses and drugs
- Extremely rare - hepatosplenomegaly, heart failure, CVA, thrombocytopenia, leukopenia
- Risk of hydrops fetalis in pregnancy
- 60% of pregnant women are susceptible to new infection
- 30% risk of transplacental infection with new maternal infection
- Affects fetal liver (main site of erythropoiesis), leading to anemia, CHF, myocarditis, IUGR
- 2-6% risk of fetal loss, highest in 2nd trimester
Pearls and Pitfalls
- Parvovirus B19 is usually a self-limited, mild illness.
- Common symptoms include "slapped-cheeks" rash with subsequent diffuse lacy rash and arthropathy
- Patients are no longer contagious when the rash appears and aplastic crisis resolves
- Evaluate all patients with history of hereditary or iron-deficiency anemia for aplastic crisis
- Evaluate all patients with history of immunosuppression for chronic infection with persistent anemia
- Confirm diagnosis in all pregnant patients. If no proven immunity, monitor for fetal complications and refer for follow-up
Additional Reading
- Servey JT, Reamy BV, Hodge J. Clinical presentations of parvovirus B19 infection. Am Fam Physician. 2007;75:373-376.
- Vafaie J, Schwartz RA. Erythema infectiosum. J Cutan Med Surg. 2005;9:159-161.
- Weir E. Parvovirus B19 infection: Fifth disease and more. CMAJ. 2005;172:743.
Codes
ICD9
057.0 Erythema infectiosum (fifth disease)
ICD10
B08.3 Erythema infectiosum [fifth disease]
SNOMED
- 34730008 erythema infectiosum (disorder)