PANCE Blueprint Infectious Disease (6%)

Erythema infectiosum (Slapped Cheek/ReelDx + Lecture)

600 REEL-DX-ENHANCED

Fifth disease ReelDx

4 y/o with low-grade fever, rash on cheeks x 24h now spreading to the trunk

Patient will present as → a 4-year-old who is brought to the office by his mother. The child has had a low-grade fever, headache, and sore throat for the past week. Four days ago, he suddenly developed a bright red rash on his cheeks, which, during the past two days, has spread to the trunk, arms, and legs. On physical examination, the child has erythema of the cheeks and a maculopapular rash with central clearing on the trunk spreading to the extremities. There are no other significant findings.

Erythema infectiosum (also known as Fifth's disease) is a common viral exanthem observed in pediatric patients caused by parvovirus B19

Diagnosis is based primarily on clinical observations, history, and physical exam

  • Serology: associated with enlarged nuclei with peripherally displaced chromatin
  • PARVO B19-specific IgM antibodies and PCR
Slapped cheek Erythema Infectiosum

Erythema infectiosum (fifth disease): Symmetrical bright red cheeks. The rash does not extend over the bridge of the nose or around the mouth.

View more images of erythema infectiosum

Observation alone

  • Treatment is symptomatic
  • The rash may last a few days to several weeks. It is frequently pruritic
  • There is no specific antiviral used and no vaccine is available
  • Parvovirus B19 is a droplet infection that is no longer contagious once the rash breaks out. Children may return to school and resume activities as symptoms allow.

osmosis Osmosis

(Erythema infectiosum lecture begins at 1:15)

Picmonic
View Fifth’s Disease

IM_NUR_EythemaIfectiosumFifthsDisease_v1.2_

Erythema infectiosum or Fifth’s Disease is a mild viral infection that is characterized by the slapped face appearance. It typically occurs in school-age children; however, adults can contract the disease. Pain and swelling in the joints (polyarthropathy syndrome) is a common finding in adult women with the disease. It is transmitted by respiratory secretions, blood, and blood products. The period of communicability is uncertain and the incubation period is 4 to 14 days and may be as long as 21 days. Isolation is not necessary.

Play Video + Quiz

Question 1
Which of the following is responsible for the skin lesion of erythema infectiosum?
A
Staphylococcus aureus
Hint:
Staphylococcus aureus can cause various skin infections, such as impetigo, cellulitis, and abscesses, but it is not associated with erythema infectiosum. The presentation of a "slapped cheek" rash and lacy, reticular rash on the extremities is not typical for infections caused by Staphylococcus aureus.
B
Parvovirus-B19
C
Herpes simplex virus
Hint:
Herpes simplex virus typically causes oral or genital lesions, known as cold sores or genital herpes, respectively. It does not cause the "slapped cheek" appearance or the lacy rash seen in erythema infectiosum.
D
Cytomegalovirus
Hint:
Cytomegalovirus (CMV) can cause a mononucleosis-like syndrome, particularly in immunocompromised individuals, but it does not typically present with the distinct rash seen in erythema infectiosum. CMV infections are more commonly associated with symptoms like fever, fatigue, and hepatosplenomegaly.
E
Rubella virus
Hint:
Rubella virus causes German measles, which can present with a rash and fever. However, the rash in rubella is different from the "slapped cheek" appearance of erythema infectiosum. Rubella rash typically starts on the face and spreads downwards and is accompanied by other symptoms like lymphadenopathy and arthralgia.
Question 1 Explanation: 
Parvovirus B19 is the causative agent of erythema infectiosum, also known as fifth disease. It typically presents in children with a characteristic "slapped cheek" facial rash, followed by a lacy, reticular rash on the extremities. The initial symptoms often include mild fever and upper respiratory symptoms.
Question 2
A 7-year-old previously healthy boy presents with several days of low-grade fever, malaise, and a “slapped cheek” facial rash. Over the next week, his rash spreads to involve his arms, legs, and trunk in a lacy, reticulated pattern. Which of the following is the most appropriate management?
A
IgG and IgM antibody testing
Hint:
IgG and IgM antibody testing may confirm parvovirus B19 infection but is unnecessary given the classic exam findings.
B
Complete blood count
Hint:
Complete blood count should be checked in immunocompromised children to rule out transient aplastic crisis but not in healthy patients.
C
Viral polymerase chain reaction (PCR)
Hint:
Viral PCR testing is used to detect viremia in high-risk groups if needed but not routine.
D
No further laboratory testing
E
Bone marrow examination
Hint:
Bone marrow examination is unnecessary as features are consistent with a benign viral illness without cytopenias.
Question 2 Explanation: 
The clinical features are classic for erythema infectiosum (fifth disease) caused by parvovirus B19. No further diagnostic laboratory testing is required in this otherwise healthy child. However, children with a known hemoglobinopathy or immunocompromised state should have viral and/or antibody testing as well as a complete blood count (CBC) and reticulocyte count to detect hematopoietic suppression.
Question 3
A 5-year-old girl presents with a classic "slapped cheek" rash and a lacy, reticular rash on her arms and legs. She has a low-grade fever and reports mild itching. Her medical history is unremarkable, and she is otherwise healthy. Which of the following is the most appropriate treatment for this patient's Erythema Infectiosum?
A
Oral Acyclovir
Hint:
This antiviral medication is effective against herpesviruses but not against Parvovirus B19, which causes Erythema Infectiosum
B
Intravenous Immunoglobulin (IVIG)
Hint:
IVIG is used in severe cases of Parvovirus B19 infection, such as in immunocompromised patients or those with chronic hemolytic anemias who develop aplastic crises. In a healthy child with typical Erythema Infectiosum, IVIG is not indicated.
C
Supportive care with antipyretics and antihistamines
D
Oral Amoxicillin
Hint:
Amoxicillin is an antibiotic and has no role in the treatment of Erythema Infectiosum, which is caused by a virus. Antibiotics are not effective against viral infections and their misuse can contribute to antibiotic resistance.
E
Topical Corticosteroids
Hint:
Amoxicillin is an antibiotic and has no role in the treatment of Erythema Infectiosum, which is caused by a virus. Antibiotics are not effective against viral infections and their misuse can contribute to antibiotic resistance.
Question 3 Explanation: 
Erythema Infectiosum, caused by Parvovirus B19, is generally a self-limiting illness in otherwise healthy children. The mainstay of treatment is supportive care. This includes the use of antipyretics, such as acetaminophen or ibuprofen, to manage fever and alleviate discomfort. Antihistamines can be beneficial in relieving itching associated with the rash. The focus is on symptom relief, as the infection typically resolves on its own without the need for specific antiviral therapy or antibiotics.
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References: Merck Manual · UpToDate

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