It's been ages since I've put out a #dermtwitter #tweetorial, so I thought what better way than to share a diagnosis that was the original motivator for me to become a dermatologist! A 🧵 on:

PEMPHIGUS VEGETANS!

#MedEd #dermatology #medtwitter #FOAMEd @healourskin #pemphigus
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What is Pemphigus Vegetans? This is where breaking down the terms can be super helpful. It's the diagnosis we give when pemphigus has the morphology of vegetative plaques.

A #tweetorial on pemphigus if you need it👇

2/
Some people think Vegetans occurs when Vulgaris goes untreated. Others think it's just a rare subtype of vulgaris.

Given the clinical findings, the path looks different with pseudoepitheliomatous hyperplasia (but still with a suprabasal split!).

pc:dermatologyadvisor.com/home/decision-…
3/ Image
This photo from @VisualDx is great at illustrating the overlap. You can see the collarettes of scale around the edge, demonstrating a prior bullous process. Yet, centrally, the vegetative plaque is the most prominent!

🌟Remember - collarettes are footprints of old blisters!
4/ Image
That said, there are 2 different subtypes with some proposed differences:

Neumann type: from longstanding vulgaris, morphology turns vegetative over time. More widespread and recalcitrant to treatment.
Hallopeau type: Presents initially with pustules instead. More limited.
5/
However, speaking from personal experience - I have seen cases of Vegetans that didn't fit either type (different type of antibody)!

The point is that this is a rare entity that clearly has its roots in pemphigus. The details after that are still being investigated!
6/
And anywhere you can get pemphigus vulgaris, you can also get Vegetans! So while it's classically in the intertriginous areas, it doesn't have to be. Check out this example of pemphigus vegetans of the scalp!
7/ Image
So what's on your differential diagnosis?

This one is more for my #dermtwitter peeps since it's a little niche, but if you have a "classic" vegetative plaque in the intertriginous areas, what would you consider?
8/ Image
I'd personally think about:

Hailey-Hailey
Vegetans
Acanthosis Nigricans
An atypical intertrigo
Contact dermatitis

There are other intertriginous eruptions like SDRIFE and hidradenitis, but the morphology is different enough to differentiate.

Here are pics of Hailey Hailey!
9/ Image
So what's the treatment? The same as Pemphigus Vulgaris. This is an antibody mediated disease, so we target the creation of those antibodies. That means medications like: Rituximab, Mycophenolate, and IVIG, to name a few.
10/
But all these medications suppress the immune system, so I don't use them lightly. I have a long discussion with my patients about their risk of infection (among other adverse effects) so that they know what to look out for afterward.
11/
SUMMARY:
✅ P Vegetans is a rare form of pemphigus, possibly from undertreatment over time.
✅ Pathology is different, with psedoepitheliomatous hyperplasia.
✅ Usaully intertriginous, doesn't have to be.
✅ Treatment is directed at auto-antibodies.

Thanks for joining!
12/12

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More from @DrStevenTChen

Apr 8
Hi #medtwitter and #dermtwitter! Since I'm giving a talk at the upcoming @SocietyHospMed Converge meeting, I thought I'd put together a brief #tweetorial on:

DIFFERENTIATING PEMPHIGUS AND PEMPHIGOID!

Follow along for a reminder on how to tell them apart!
1/ Image
Reminder that Pemphigus is from an antibody targeting the Desmosome - which holds skin cells (keratinocytes) together.

Pemphigoid is from an antibody targeting the Hemidesmosome, which holds keratinocytes to the basement membrane.
pc:
2/ bookdown.org/jcog196013/BS2…
Image
So to remember:

pemphiguS (S for Superficial/higher up)
pemphigoiD (D for Deep/lower down)

This also means the clinical exam is different. Since Pemphigoid is deeper, these bullae stand tall and proud and don't droop over (see pic)! We call these TENSE bullae.
3/ Image
Read 9 tweets
Oct 23, 2023
If everyone could just humor me for a little, here's a #dermtwitter/#medtwitter/#pharmtwitter #tweetorial on...

AZATHIOPRINE

Did you know that dermatologists use this medication too? Read on to see all the ins and outs of safety and dosing, from a #dermatology point of view!
1/ Image
Did you notice those two rings above? That's how it works.

Azathioprine is a purine (see figure) analogue, so it gets in the way of RNA/DNA synthesis (making transcription and replication and all that downstream goodness more difficult).
2/ Image
And as you might imagine, cells that are rapidly dividing (like your immune cells) would be affected more by this purine disruption.

But it's not azathioprine itself that does all the work. It has to be broken down into active metabolites and that's where it gets interesting.
3/ Image
Read 15 tweets
Jul 18, 2023
Time for a #dermtwitter/#medtwitter #tweetorial on...

LYME DISEASE

#Meded #FOAMEd

PC:
1/ https://t.co/E9DgXHQDFNphil.cdc.gov
Image
Let's start with the basics. What causes Lyme?

The spirochete Borrelia burgdorferi is the most common cause. It is transmitted via tick bite, and so, certain areas of the country have higher rates based on endemicity of the organism.

What tick classically transmits lyme?
2/
Ixodes tick is the classic vector for B burgdorferi. But remember:

The tick usually has to be attached to the patient for >36 hours to transmit and cause Lyme disease.

Can you identify all these types of ticks and pick out which one is Ixodes?

pc:
3/ https://t.co/efyjpcWBnUcdc.gov/ticks/tickborn…



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Read 16 tweets
Jun 9, 2023
We're seeing more consult questions for this, and it's also garnering national attention, so let's take a brief moment in #tweetorial format to talk about:

XYLAZINE SKIN ULCERS!

#xylazine #MedEd #FOAMEd #dermtwitter #medtwitter

1/
What is Xylazine? It was created in the 70s as a veterinary anesthetic. As an analog of clonidine, it has similar effects as an alpha-2 agonist, leading to sedation, anesthesia, and euphoria in the CNS.
2/ Image
Recently, Xylazine has entered the drug supply, moreso in certain cities, but increasingly everywhere. It is often mixed with fentanyl as a cutting agent, and can also be used on its own. It may be called Tranq, Zombie Drug, or anestesia de caballo (horse anesthetic).
3/
Read 12 tweets
May 16, 2023
Let's go back to the basics. Syphilis is from an infection by the bacterium Treponema pallidum. Usually spread by sexual means, syphilis has three main stages of disease.

Primary infection usually presents as a papule that turns into a painless ulcer called a chancre.
2/ Image
Time from inoculation to chancre usually is 10-90 days (21 days is most typical).

There is a rare variant where the patient can get many smaller ulcerations, which is called Follman balanitis.
3/ Image
Read 16 tweets
Jan 31, 2023
DERMATOMYOSITIS (DM)

Let’s spend some time in this #tweetorial on the dermatologic manifestations of this potentially paraneoplastic disease!

First, a question: What is necessary to make a diagnosis of DM?
1/
None of the above! DM is a clinical diagnosis, which is why getting the exam right is super important! That said a biopsy CAN help with getting to a diagnosis, but it’s not necessary.

So let’s start! Heliotrope rash! This poikilodermatous erythema occurs around the eyes.
2/
Remember though that exams are different across skin tone. Heliotrope can look a lot more subtle in someone with more melanated skin. That rash can also include the rest of the face!
3/
Read 19 tweets

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