Steven Chen Profile picture
Dermatologist/internist at #MGH - interest in complex/onco #dermatology & #MedEd | #Harvard Derm APD | Father | Husband | Karaoke enthusiast. Tweets are my own.
Reza Hosseini ⚕️ Profile picture medicalmoe Profile picture Karen Liaw Profile picture 4 added to My Authors
1 Aug
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METHOTREXATE!

A #tweetorial for #medtwitter, #dermtwitter, & #medstudenttwitter!

I'm no pharmacologist, so this is written from a #dermatologist's POV!

Let's start with a question that still haunts med students today:
What is the mechanism of action of methotrexate (MTX)?
2/
MTX inhibits dihydrofolate reductase in the folate pathway, which is needed for DNA/RNA ➡️ inability for cells to rapidly divide!

Given similarities in mechanism with other drugs in this pathway, caution should be used when adding MTX on top of them, especially TMP-SMX!
3/
Since MTX is an antifolate, remember that Folinic Acid (Leucovorin) is used as a "rescue" when side effects go crazy. But at the doses we use in #dermatology, I've never needed it. Plus, we give folate with MTX to prevent these effects!

Which of 👇 doses is typical in derm?
Read 18 tweets
25 Jul
LICHEN PLANUS

A #dermtwitter, #medtwitter, and #medstudenttwitter #tweetorial! PC: @dermnetnz. Let's kick off this #MedEd #FOAMEd #medthread with a question.

With LP, which one of the following body sites is most commonly involved?

1/
The correct answer is wrists! LP lesions are most commonly seen on flexor wrists, trunk, medial thighs, and shins. It very rarely involves the face.

The mnemonic for the clinical appearance of LP is to remember the "Ps."
Pruritic (!!!)
Purple
Polygonal/Planar
Papules

2/
You can also make out white and gray lacy streaks and puncta. This is called "Wickham Striae" which helps confirm the diagnosis (1).

Notably, LP also can go to the oropharynx, which can cause erosive lesions that are painful. Wickham Striae are easier to see in the mouth (2).
3/
Read 14 tweets
19 Jul
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Hello #medtwitter & #dermtwitter, time for another #dermatology #tweetorial! Let’s go back to the basics and talk about:

#ACNE!

Hopefully this #meded/#foamed moment is helpful for all the #maskne in the #covid19 era!

Let’s start with a simple question:
What causes acne?
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All of the above! Often, every one of these factors plays some role. What’s important is knowing what treatment to emphasize based on what factor seems to be the biggest influencer.

For example:
-Retinoids for cell turnover
-Ocps for hormones
-Antibiotics for bacteria!
3/
Let’s talk exam. When I see an acne patient, I’m looking for what lesion I see most: comedones (white/blackheads), inflammatory papules, or cysts.

I’m also looking at distribution (where on the body) and the severity.

It’s critical to ask if it’s a good, typical, or bad day!
Read 16 tweets
2 Jul
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#AGEP (ACUTE GENERALIZED EXANTHEMATOUS PUSTULOSIS)!

A #medtwitter #dermtwitter #tweetorial! #MedEd #FOAMEd

This is a drug reaction that we can see on inpatients, with an exam full of pustules!

Let's start with a question - How long after drug exposure does AGEP appear?
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The correct answer is 24-48 hours!

The other answers are typical time frames for other types of reactions.
Urticaria usually manifests minutes to hours after drug exposure.
Morbilliform drug eruptions occur 4-14 days after drug exposure.
DRESS occurs 2-6 weeks afterward!
3/
Unlike DRESS and morbilliform eruptions, AGEP doesn't require repeated exposure of drug. So one single dose can definitely cause AGEP. A typical place we see this is with perioperative antibiotics!

Common culprits are Penicillins, quinolones, sulfa, antifungals, and CCBs!
Read 12 tweets
5 Jun
I'm in awe of the #whitecoatsforblacklives effort across the country. To see the unity on display everywhere is truly moving.

I'm sure I missed a bunch, but I put together a #thread here of all the posts from institutions today.👇

#BlacksLivesMatter #medtwitter
Read 28 tweets
30 Apr
All right #dermtwitter & #medtwitter, it's time for the...

@MedDermSoc & @DermHospitalist Mini-Symposium on #COVID19 & #dermatology!!

I will be attempting to #livetweet the Zoom meeting!

Join along if you'd like. I will be using the h/t #COVIDDerm!

@RoxanaDaneshjou @dschless
Let's get started!!!!

Your cohosts are super excited to have you join. To give a little background, this meeting was planned in ~1 week, and we have over 500 RSVPs!

@MishaRosenbach now kicking us off with #COVIDDerm! Image
.@DrEstherFreeman is speaking and reminding us all to register our #COVID19 #dermatology cases in the @AADskin #COVID registry!

Reminder to do so here:
aad.org/covidregistry

#COVIDDerm
Read 39 tweets
20 Apr
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Okay #medtwitter and #dermtwitter, you knew it was only a matter of time, didn’t you?! Let’s do this #COVID19 themed #medthread:

#COVID TOES, a #TWEETORIAL!

#MedEd #FOAMEd #dermatology #dermatologia @AADskin @AADMember @Meddermsoc @dermhospitalist
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First, a word of caution – this is one person’s thoughts on a new skin finding reported in a new disease that the medical community is still learning about! As such, nothing in the #tweetorial should be regarded as definite. Just wanted to share a thought process!
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So, who cares? #COVID19 is devastating, at times even for the young & healthy! But it’s all respiratory, right?

Well, as we're learning, there's so much more to #SARScov2, and as a #dermatologist, this is the perfect example of how the exam helps frame possible mechanisms.
Read 12 tweets
3 Apr
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Day 3 of #DistanceMedEd for #dermtwitter and #medtwitter! We've done 2 of the 5 reaction patterns so far, so let's focus in on the....

DERMAL reaction pattern!

#MedEd #FOAMEd #tweetorial #medthread PC: @dermnetnz
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As opposed to the papulosquamous reaction pattern, the dermal pattern implies the action is DEEP in the DERMIS. This means that without epidermal alteration, you shouldn't see scale!

There is of course an exception with overlying xerosis or if you have another process on top!
3/
When you see something dermal, you have to think about what is infiltrating the skin. A few possibilities/examples:

Edema/fluid 👉 urticaria (1)
Inflammatory cells (reactive) 👉 granuloma annulare (2)
Inflammatory cells (cancer) 👉 CBCL (3)
Collagen 👉 Morphea (4)
Read 8 tweets
2 Apr
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2nd installment of #dermtwitter #DistanceMedEd. Today's #tweetorial will be a brief one on...

VESICOBULLOUS REACTION PATTERN!

#MedEd #FOAMEd #dermatology #medtwitter

PC: @dermnetnz
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First things first - some definitions:
Vesicle: fluid filled <1 cm
Bulla: fluid filled >1 cm
Pustule - Filled with pus
- Ahem, the word you're looking for describe something with a lot of pus is "purulent," not what you're thinking....🤨
3/
Next, the name is self explanatory. The vesicobullous pattern implies you're seeing vesicles or bullae. There is one very important exception:

If you see COLLARETTES of scale (round pattern of scale remnant), these can indicate a prior vesicle or bulla (like an old footprint)
Read 10 tweets
1 Apr
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Motivated by @TedWJamesMD to put together a #dermtwitter/#medtwitter #tweetorial for #DistanceMedEd today.

Let's do one about PAPULOSQUAMOUS DISORDERS of the skin.

What would be a good example of a papulosquamous rash you might see on #skinexam?

PC: @dermnetnz
2/
Psoriasis is the perfect example of a papulosquamous disorder. Before we break down what this means, let's start with the basics. I was taught that skin rashes & lesions fall in one of 5 reaction patterns:
- papulosquamous
- eczematous
- vesicobullous
- dermal
- red (vascular)
3/
By knowing which category each rash/lesion is, you can limit your Ddx.

For example:
If something is both vesicobullous and eczematous, you're probably dealing with some type of eczema.
If you're dealing with something dermal, you can probably take psoriasis off your ddx!
Read 9 tweets
26 Mar
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In an effort to conserve #PPE & increase #socialdistancing, many #dermatology services have switched to a heavily #telemedicine model. So today, I present to you:

HOW TO TAKE PHOTOS & CALL A #DERM CONSULT - a #covid19 era #tweetorial.

#MedEd #FOAMEd #dermtwitter #medtwitter
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Let's start with appropriateness of consult. We are trying hard to limit nonurgent consults for the above reasons. The following can wait for when #coronavirus isn't everywhere.
- nonmelanoma skin CA
- old rashes with a known dx
- missed a derm appt and happens to be in house
3/
If it's an urgent issue, it's helpful to start with the photo. Any camera phone should be fine. If on Epic, you can use Haiku to upload directly the the EMR.

NB: texting photos isn't HIPAA compliant. We'll usually refer to the EMR, or email the photos in a secure system.
Read 9 tweets
19 Mar
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HOW TO TREAT ACTINIC KERATOSES AT HOME, a #tweetorial/#medthread

AKA:how to keep practicing #socialdistancing in the era of #COVID19 by staying at home and taking care of those precancers without having to come to clinic!

#dermtwitter #medtwitter #MedEd #FOAMed pc:@dermnetnz
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1st, a caveat. Nothing subs for an in person exam, so this is not free license to tx things without a derm eval.

The reason for this #thread is that as the doctor seeing all urgent #dermatology pts today, I've gotten MANY calls from pts hoping to come get their AKs treated.
3/
Before we get to txs, let's start with the basics. What is an AK?

Clinically they are erythematous papules & plaques with gritty (sandpaper-like) scale. Some can be quite big. Then we call them "hypertrophic AKs."

These are precursor lesions to squamous cell carcinomas.
Read 13 tweets
8 Mar
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BULLOUS PEMPHIGOID, a #dermatology #tweetorial!

#MedEd #FOAMEd #medtwitter #dermtwitter #medthread pc:@dermnetnz

A patient with active bullous #pemphigoid comes to see you. What do you expect on your exam?
2/
#bullouspemphigoid (BP) is an autoimmune blistering disorder where the pt's immune system makes auto-antibodies targeting BPAg 1&2 (BP230/BP180). Since these Ags are in the hemidesmosome, the split is lower in the skin, making for tense blisters.

pc: sciencedirect.com/science/articl…
3/
Clinically, tense blisters (as seen in BP) usually go with a negative nikolsky, whereas flaccid blisters (seen in pemphigus) would have a positive nikolsky.

An easy mnemonic is:
pemphiguS = Superficial
pemphigoiD = Deep
Read 13 tweets
17 Feb
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ATOPIC DERMATITIS - a #dermatology #tweetorial/#medthread!

For all the #tweetiatricians, #primarycare, #medtwitter, & #dermtwitter! #MedEd #FOAMEd pc:@dermnetnz

1st, a question:
How do you think of the term atopic dermatitis (AD) in relation to the term eczema?
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If you're a purist, "eczema" is a description. When a #dermatologist says something looks eczematous, it doesn't mean it's AD. It means it has a certain appearance.

So the right answer for purists is "AD can cause eczema."

That said, we so often just use eczema to mean AD🤷🏻‍♂️
3/
As annoying as that might be, it's an important distinction. If you see an eczematous rash, you need to consider possible causes:

- Atopy
- Allergy/irritant contact
- Medications
- Venous stasis
- Dry skin

For more on contact dermatitis, check out @patchtestYu!
Read 16 tweets
18 Jan
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STAPHYLOCOCCAL SCALDED SKIN SYNDROME - A #dermatology/#dermtwitter #tweetorial!

Let's start with a question: You are seeing a new patient with a rash you suspect of being SSSS, but aren't sure if it might be bullous impetigo.

What test will help you differentiate the two?
2/
The correct answer is wound culture! SSSS should be sterile or skin flora; bullous impetigo will have lots of staph grow out. Keep reading to find out why! 👇

But before we get there, let's talk about the SSSS exam. The pic is a good example of "sad facies." pc:@dermnetnz
3/
The other great clue you are dealing with SSSS is the predilection for skin folds. This eruption can cause a high BSA of erythema --> desquamation.

SSSS is more common in the #pediatrics population, especially in kids <5 years of age (for all the #tweetiatricians out there!)
Read 14 tweets
25 Dec 19
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Why exactly do the lesions in pityriasis rosea appear in the “Christmas Tree” pattern?

Well, in honor of today being #Christmas, let’s do a brief #dermatology/#dermtwitter #tweetorial on…

PITYRIASIS ROSEA!

So what say you? What’s the reason for the Xmas Tree pattern?
2/
PR presents in "Langer's Lines," aka the skin tension lines. This paper notes diseases in this pattern seem to have activated leukocytes in the pathophy, which could be explained by other papers looking at how skin stretch impacts immune response!

sciencedirect.com/science/articl…
3/
This same paper points out a limited group of skin diseases that can have this distribution:

- PR
- Secondary syphilis
- Sign of Leser Trelat
- Mycosis Fungoides

Ultimately, the cause of this distribution might have to do with skin tension, but is best described as unknown.
Read 11 tweets
1 Dec 19
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“The Erythemas” – A #dermatology #meded #FOAMEd #tweetorial. pc:@dermnetnz

Ever get all the different #dermatologic terms jumbled up? Was it erythema nodosum, erythema migrans, or erythema multiforme?

Honest poll – Ever write “rash” b/c you couldn’t remember the diagnosis?
2/
All kidding aside, these terms can get confusing. Remember though, derm terms are usually just descriptors of what you see. The name tells you all you need to know.

For example: Acute Generalized Exanthematous Pustulosis (AGEP) = pustules suddenly appeared everywhere!
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So, the “erythemas.” First off, what does “erythema” actually mean? Well, according to my Google machine, it's from the Greek root “eruthros” meaning “red.” So "erythema" doesn’t add much to our knowledge of what the rash looks like other than it’s red, and so, likely inflamed
Read 15 tweets
14 Nov 19
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ERYTHEMA MULTIFORME – a #dermatology #tweetorial/#medthread!

#MedEd #FOAMEd #dermatologia #dermtwitter #medtwitter #derm pc: @dermnetnz

Let's warm up with a question for all y'all tweeps out there!

What is the most common trigger for erythema multiforme (EM) in adults?
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EM is an immunologic syndrome usually triggered by infection in adults. We usually consider HSV and mycoplasma. A simple history for cold sores or genital ulcers can be telling, but mycoplasma can go undetected symptomatically.

What primary lesions do you expect in EM?
3/
EM is usually made up of papular (raised) targets. Pic1 is of EM; you can see the 3 zones in a typical target (red rim, then white, then red center). Versus SJS/TEN (pic2), where macular targetoid (2 zones of red rim, dusky center & flat).

2nd photo: my.clevelandclinic.org/health/disease…
Read 10 tweets
27 Oct 19
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VENOUS STASIS LEG ULCERS!!!

A #tweetorial for the #dermtwitter, #medtwitter, #medstudenttwitter, and #hospitalist crowd. 📸:@dermnetnz #medthread

Let's start with a question - What percentage of leg ulcers do you think is caused by venous stasis?
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Roughly half (40-50%) of all leg ulcers are the result of venous stasis! Since 1% of the population will get stasis ulcers at some point, it's quite common, both in the inpatient & outpatient settings!

While some say they aren't painful, many of my patients would disagree....
3/
Let's talk exam. These ulcers are predominantly on the lower legs, and often near the medial malleolus. They're usually chronic, so they may have a base covered by yellow fibrinous debris. They tend to be shallow, and given the pathophysiology, quite exudative.
Read 15 tweets
19 Oct 19
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ACUTE SKIN GRAFT-VERSUS-HOST DISEASE:
A #tweetorial/#medthread on this complication of stem cell transplantation!

#MedEd #FOAMEd #dermtwitter #onctwitter #medtwitter #dermatology #dermatologia pc:@dermnetnz

1st, a poll:

How do you differentiate acute & chronic skin #GVHD?
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Acute vs. chronic GVHD is usually differentiated by when it occurs: before or after 100 days since allogeneic stem cell transplant. BUT in the skin, MORPHOLOGY is key!

As with almost everything else in derm, start with the exam. That will tell you what you're dealing with!
3/
Acute GVHD is usually morbilliform, which means "measles-like." Morphologically, we describe this eruption as "3-4 mm pink papules that coalesce into plaques." Whenever we see this in a SCT pt, the ddx includes the following:
- acute GVHD
- morbilliform drug
- viral exanthem
Read 14 tweets
6 Oct 19
Syphilis! RMSF! Hand-foot mouth!

Slow down there, Tiger! Let's dive deeper into:

ACRAL RASHES - a #tweetorial/#medthread
(aka rashes on the "palms and soles" - kind of 😉).

#MedEd #FOAMEd #medtwitter #dermtwitter #dermatology #dermatologia pc:@dermnetnz
1/
No where else on the body does a rash evoke more of a knee-jerk differential. That's not wrong per se, as we all learn this in med school, but it's more complicated then starting doxycycline and checking an RPR!

Let's start with a definition - what does "acral" actually mean?
2/
Technically, "acral" just means our distal body parts. So while we often think of palms and soles, it's actually inclusive of the whole hand, the whole foot, ears, and some include even the nose!

I actually didn't learn this until #derm residency, which was shocking to me.
3/
Read 20 tweets