Viral exanthems of childhood: Pathology review

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Viral exanthems of childhood: Pathology review

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A 3-year-old boy is brought to the office by his parents due to a facial rash. The parents report the patient has been having a runny nose, diarrhea, and a fever of up to 38.3 ºC (100.9 ºF), for the past three days. Today, the patient developed a rash on his face, shown below. Laboratory evaluation is significant for a hemoglobin of 9 g/dL and a leukocyte count of 3000 cells/mm3. Which of the following best describes this patient's characteristics of the causative organism?
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A 1 year old boy named Adam is brought to the pediatric clinic by his mother, who is concerned because Adam developed a pink skin rash that began in the trunk and has now spread to the extremities.

On physical examination, the rash appears to be maculopapular. Upon further questioning, she recalls that Adam had a high fever for the past few days, and the rash appeared after the fever went down.

Next you see Rose, a 9 year old girl who came in with her father, due to a very itchy rash all over her body. Her father claims that the rash started 2 days ago after having a mild fever, and that several of Rose’s schoolmates also have the same rash.

Upon physical examination, you notice that the rash involves her face, trunk, and extremities, and presents with different types of lesions, including papules, vesicles, and crusts.

Now, based on the initial presentation, both Adam and Rose seem to have a viral exanthem of childhood, which is a group of eruptive skin rashes caused by viral infection and usually affect children.

Generally, viral exanthems can be macular, papular, maculopapular, or vesicular. A macular rash has macules, which are up to 5 mm in diameter, and completely flat, meaning that you can’t feel them if you run your finger over them.

On the other hand, a papular rash has papules, which are raised bumps that are up to 1 cm in diameter. And a maculopapular has both macules and papules.

Finally, a vesicular rash has vesicles, which are up to 5 mm in diameter, and look like clear blisters filled with fluid. Viral exanthems of childhood include varicella; hand-foot-mouth disease; roseola infantum; measles; rubella; and erythema infectiosum.

Alright, now one of the most common viral exanthems is varicella, more commonly referred to as chickenpox. It is caused by the varicella-zoster virus, or VZV for short, which is a DNA virus, and is also known as human herpesvirus 3 or HHV-3, as it belongs to the Herpesviridae family.

Now, this is a highly contagious airborne virus, meaning it’s transmitted from person to person through respiratory droplets; for example, when an infected person sneezes or coughs.


Viral exanthems of childhood are skin rashes that often affect children, and include varicella, hand-foot-mouth disease, roseola infantum, measles, rubella, and erythema infectiosum. Each has distinct symptoms and is caused by a different virus.

Varicella or chickenpox is caused by the varicella-zoster virus. It causes flu-like symptoms and a vesicular rash that spreads to the extremities and face. Measles caused by the measles virus leads to a high fever and a maculopapular rash that spreads in a cephalocaudal progression. There is also rubella caused by the rubella virus, which leads to flu-like symptoms and a maculopapular rash that spreads cephalocaudally, and can be transmitted by a pregnant individual to the fetus via the placenta.

Next is Hand-foot-mouth disease caused by the virus Coxsackievirus group A, which results in flu-like symptoms followed by a vesicular rash that begins in the mouth. Roseola infantum, which is human herpesvirus 6, presents with a high fever and a rose-colored maculopapular rash. There is also Erythema infectiosum caused by parvovirus B19, which presents with flu-like symptoms and a characteristic "slapped-cheek" rash, and can cause anemia in individuals with certain blood disorders or fetal anemia if contracted during pregnancy.


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  4. "CURRENT Medical Diagnosis and Treatment 2020" McGraw-Hill Education / Medical (2019)
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  6. "Coxsackievirus A6 and Hand,Foot and Mouth Disease:Three Case Reports of FamilialChild-to-Immunocompetent Adult Transmission and a Literature Review" Case Reports in Dermatology (2013)
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