Here we see the timeline of the signs and symptoms of varicella.
On the left, you'll see your patient's going to be exposed to the virus
then they're gonna enter the incubation period and this can be up to 21 days
before they start showing symptoms.
Next, your patient's going to develop classic cold-like symptoms.
They may have a fever, fatigue, headache, malaise.
Patients can get a runny nose and a cough so to assist in your diagnosis,
you always want to inquire whether or not the patient
had cold-like symptoms preceding their rash.
Next, the rash is going to appear and this is an itchy blister-like rash
and it's typically found on the trunk and limbs
but I've even seen patients with lesions in their mouth.
They're gonna progress through their infectious period until all of these lesions are scabbed
and then the patient will experience complete resolution.
This rash is pretty classic. It's gonna start as a papule.
These are red bumps that are raised and appear over several days and this is really key.
They don't all appear at once. Then they turn into a vesicle.
They're gonna fill with fluid and these look like blisters.
And this happens in about one day and then they're going to break and leak.
Finally, they're gonna crust and scab over.
Characteristics of the chickenpox rash are that these children
are gonna have papules and vesicles in different stages of maturity
since these crop up over a few days.
Now, I've had patients come in and they're early on in their chickenpox
and it looks like they kinda have bug bites.
I asked the parents. 'Have you noticed these appearing over a sequence of days
or did these all appear at once?'
Typically, if a patient has bug bites, they'll get them all at once,
they were playing outside but when patients have chickenpox,
each day they're gonna get new lesions. This can help in the diagnosis.
The rash has also been described as resembling a dewdrop
with is the vesicle on a rose petal which is a little bit of erythema.
The patient usually has these legions, again, in all 3 phases
and typically will have 200-400 lesions in a sequence of 2-4 crops.
Here we see the classic phases.
Again, you have red or pinkish bumps in the first phase
then these are gonna turn into vesicles and they're gonna become fluid-filled.
Finally, they're gonna crust and scab over.
Here's another sequence and this varies based on the patient
and it varies based on the severity of their chickenpox
but you can see Day 1, not a big deal.
Day 2, they might still be going to work and school.
Maybe they think they had some, you know, a mild cold followed by some bug bites.
But then as the day's progress, these lesions mature and change.
Chickenpox is usually diagnosed based on a complete medical history and a physical exam.
You're gonna start with the vital signs of your patient.
This is always a good place to start.
They're usually normal when your patient comes in with chickenpox.
Next you move down to the head, eyes, ears, nose, and throat exam and this needs to be thorough.
Next you'll do a cardiac exam and a respiratory exam.
And finally, you check the skin.
You'll want to look at the patient's skin looking for all different lesions
and seeing if they're raised, seeing if they're tender,
and looking for other signs of infection like secondary bacterial infections.
So how do we diagnose chickenpox?
Well, it's mainly a clinical diagnosis based on the history and the telltale rash.
So if you kinda have a patient come in to be checked for chickenpox,
you wanna try to encourage the parents to call the clinic first
to avoid exposing all of the other patients in the waiting room during the visit.
So one of my children actually had chickenpox after he was vaccinated
and we've gone camping. And throughout the week,
we all had our itchy bug bites from camping and sleeping out in the woods
and he was getting new lesions every day.
Well, he'd been going to school all week and by the time it got to Friday,
I realized that all of our bug bites had resolved and he was getting these new lesions.
So I called the pediatrician and I said, 'Sorry, I've sent my kid to school all week.
I think he has the chickenpox.' And they said, 'Well, he's had his vaccines.
That's not that common but we'd like to see him.'
So they asked me to call. I parked in the parking lot and called the pediatrician's office
when we got there and the nurse came out and let us in through the backdoor,
the rush door, and into a private isolation room.
And it turns out, clinically, the providers did diagnose him with chickenpox.
There are other ways to diagnose.
You can do a varicella-zoster PCR
and I do this in the clinic if the patient has a lesion that is just a little bit ambiguous.
You're not quite sure. And to do this, you'll use a viral swab
and you'll find the really juicy lesions and they need to be unroofed
so this can take a little bit of effort. It can be a little bit painful.
And you'll swab on the lesion, get the juice, and send it to the lab
and they'll be looking for the varicella-zoster DNA.
Another is the Tzanck smear.
You can do a viral culture but again, this takes time to get the results.
Blood work can be done including an IgM
and remember, this is your antibody that shows up early with acute infection.
And then IgG and this is your patient's titer.
This is the antibody made later and this shows their subsequent immunity.
In utero, this should be done at least 5 weeks after a mother has a primary maternal infection
and this can be done on ultrasound or a PCR test of the mother's amniotic fluid can be done
but remember, an amniocentesis is a high risk procedure.