Now let's cover erythema infectiosum which is fifth disease.
A long time ago, fifth disease got its name
because it was the fifth on the list of six commonly recognized childhood rash forming illnesses.
And this is caused by an infection with the parvovirus B19.
The incubation is 4 to 21 days and it's found more commonly in the spring.
It's transmitted via respiratory secretions, including cough, saliva and sputum or contact with infected blood.
Now, this can also be transmitted vertically in pregnancy.
Usually this affects school-age children, daycare workers, teachers and parents.
It's most infectious prior to the onset of symptoms.
But once a patient's symptomatic, they're no longer contagious so no isolation is necessary.
Let's talk about the parvovirus B19.
This is gonna cause a transient suppression of erythropoiesis.
It's usually mild and asymptomatic.
These immunocompromised children can develop a protracted viremia though for weeks to months.
Typically in the healthy population you won't see this.
Patients with hemoglobinopathy is like sickle cell disease,
can develop an aplastic crisis if they get parvovirus B19.
And it's usually self-limiting and usually mild. There's phase 1.
This is where the patient gets sick.
They have a low-grade fever, a headache, a rash and cold like symptoms.
This is pretty low on a parent's radar.
Next, the child will develop a rash and this is phase 2, a few days later.
They're gonna start with a bright red rash on their cheeks.
It's described as a slap cheek look and it is classic.
They'll also develop a red lacy rash on the rest of their body.
And once this rash develops, the child is no longer contagious.
The rash can wane and wax and temporarily reappear during this phase.
Adolescents and adults can get a self-limited arthritis.
So when you're examining a patient that you suspect might have fifth disease,
you're gonna collect a medical history.
You're also going to review the child's immunization status and this is to exclude other causes of fever and rash.
Your gonna do a physical exam, including, looking at the vital signs,
a complete, head, eyes, ears, nose, throat exam.
You're gonna do a cardiac, respiratory and full skin exam.
So how do we diagnose fifth disease?
This is a clinical diagnosis which means you use your history
and your physical exam to drive your diagnostics.
There is no lab work or testing needed especially in children.
But you'll do this if a child has a known blood disorder or an impaired immune system
because these are the children at risk for complications.
Fifth disease is a self-limiting viral infection. Antibiotics are not effective because remember, this is a virus.
Most children are gonna feel totally fine and be playing and running around when they have fifth disease.
You can do symptomatic care for their cold-like symptoms but it's usually not necessary.
A child can have acetaminophen for their fever or joint pain if they need it.
The rash may be itchy so you want to avoid hot showers and hot baths because this can make an itchy rash even worse.
And remember, no aspirin in the pediatric population because this can cause Reye's syndrome.
And this is a rare but serious condition that causes swelling in the liver and brain.
So what are the complications?
Well, typically in healthy children, there won't be any complications.
They're just gonna have a very mild illness. In the pregnant population, this can be very serious.
It can be linked to hydrops fetalis which can cause spontaneous abortion also known as a miscarriage.
In patients with sickle cell anemia, they can develop an aplastic crisis.
And in the immunocompromised patients, they can be at increased risk for complications.