You've seen rashes and called them all "maculopapular," because, why not?

Does describing something accurately really make a difference?

9 words to improve your life... when calling a derm consult.
Macules are flat lesions, less than 1 cm in diameter.

If you closed your eyes and ran your finger over it, you wouldn't feel where it starts and stops.

👀Idiopathic guttate hypomelanosis Shins with hypopigmented maculesHypopigmented macules on the arm
Papules are raised (or depressed) lesions, less than 1 cm in diameter.

Unlike macules, if you closed your eyes and ran your finger over it, you'd be able to tell where the lesion is.

👀Compound nevi 2 discrete hyperpigmented papules on the left cheek
Patches are big macules (> 1 cm)

👀Vitiligo Left jaw/chin with depigmented patch
Plaques are big papules (> 1 cm)

👀Psoriasis Salmon colored plaques on the knees and shins
Nodules are deeper seated lesions, think at least 1 cm deep. It's hard to measure though because part of it is under the skin surface.

👀Rheumatoid nodule Pink nodule on the PIP of the index finger. Pink plaques on
Tumors are even bigger. People disagree, but 2 cm is a reasonable cut off.

👀Cutaneous T-cell Lymphoma Tumors on the posterior/occipital scalp
Vesicles are fluid filled blisters that are <1 cm.

👀Herpes Zoster (Shingles) Cluster of vesicles on a pink base
Bullae are bigger blisters, >1 cm!

👀Bullous Pemphigoid Discrete 1-3 cm tense bullae on the extremity.
Pustules are anything filled with pus.

Remember the adjective for them is "purulent," not the other word you're thinking of.

👀Folliculitis Discrete follicularly based pustules.
This has been a parody #tweetorial on #morphology!

Remember, these are primary lesions, and there's so much more you can say about the rash! Check out my original series by searching for #derm101.

#dermtwitter #medtwitter #meded #FOAMEd
📸: @visualdx

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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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