149 Acne vs Rashes – How To Think Through Derm Questions And Pick up Easy Points

Good morning and welcome to this special holiday edition of the Physician Assistant Exam Review Podcast. I’m up early here on New Year’s Eve. I’m getting this recorded before my kids are up. And today we’re going to start by jumping into dermatology.

All right. My name is Brian Wallace. I’m the host and creator here at Physician Assistant Exam Review. And today we’re going to be starting Derm. Like I said, we finished up GU. I’ve got all the notes over on the website, physicianassistantexamreview.com. Then if you head under Blueprint, you can find all the notes, all the information there.

I’ve been actually stockpiling this section and I’m going to turn it into a really nice review book with questions and some guided tactics and things I’ve been building on the back end as I go through it, through the through the material this time. So something I’m really looking forward to is taking me a lot of time just with the GU section. But I’m jumping into derm and hopefully there’ll be a maybe a volume one edition with with the first few topics, something like that coming out in early 2026. We’ll see how things go. But I want to remind you up front that this podcast is different from everything else out there. This is not about just the medical facts. It’s about how to think and study and perform on high stakes exams.

That’s the real differentiator here. We are going to take medical content and we’re going to go through it as the backdrop for what we’re doing. But what we really want to do is make sure that it’s sticking in your head, that you can recognize it on exams, that you can organize it to study and avoid common traps on tests. That’s our goal here. So we use the dermatology as the backdrop for that, but we do it with a different focus. We don’t just present the information. Remember our motto is to think different, work different, score different.

I just had a couple of people this week email me with scores they weren’t hoping for on their PANCE. Always devastating. And I’m looking forward to working with them and helping them. But it drives me crazy that both of them said, hey, I only just stumbled across the podcast. Hey, I only just saw you on Instagram. A friend recommended you was another one. And that kind of thing kills me because I don’t do a good job of promoting the show, of promoting the work we do here, promoting 33 Days.

I’m so focused on creating the content, quite honestly, and running 33 Days that I don’t do a good enough job going out into the world and making sure students have these tools. I’m going to try to focus more on that in 2026. It’s definitely on my high, high list of priorities, but I’m also going to ask you to help me take care of that a little bit. And if you get something out of the show, share it with a friend, share it with a faculty member who can then help other students. I absolutely hate it when students come to me after having failed the PANCE because there’s so much we can do before that.

All right, so let’s jump in and get started with our priming questions for today. I structured these a little different. These are designed to help you think through some problems before we get to the content, designed to build like a little scaffolding or little hooks for you to hold the information on and to keep you from just drifting off during the show so that you’re actually actively engaged and working.

So let’s see how you like these. A facial rash has papules and pustules, but no comedones. What two diagnoses should you be thinking of? A facial rash has papules and pustules, but no comedones. What two diagnoses should you think of first? If a skin lesions are itchy and centered on hair follicles, what exposure or activity do you need to ask about? This would be if you’re in the clinic, right?

To have a patient come in and they’ve got itchy skin lesions that are on follicles, What exposure activity should you be asking about? A rash worsens after using a topical steroid on the face. What diagnosis should immediately come to mind? This should just be linked. It should just be one gives the other. A rash begins with one large lesion, then spreads across the trunk days later. What pattern do you expect for that spreading?

This is sort of a two-parter, a little more difficult. A rash begins with one large lesion, then spreads across the trunk days later. What pattern are you looking for? And number five, a thick scale is present on the skin. What two features help you decide between psoriasis and seborrheic dermatitis? Thick thick scales present on the skin. What two features help you decide between psoriasis and seborrheic dermatitis?

All right. Today, we’re going to cover acneiform eruptions and papulosquamous disorders. I grouped these together because I think it’s how you may see things on the exam. You’re going to push things up against each other, obviously, that look similar, that patients walk into the office with, that you’re going to have to choose between. So we’re grouping this together to get started. Acne vulgaris is a chronic inflammatory disorder of the pilosebaceous unit. This is the hair follicle and its attached oil gland is all that that means.

It’s caused by an increased sebum production, follicular hyperkeratinization, colonization with Cutibacterium acnes, and inflammation. Most common in adolescents and young adults. That’s really important here, right? That’s where you’re going to see this the most. Adolescents and young adults. Clinical presentation. The hallmark sign here is the open comedones, so those blackheads, and the closed comedones, the whiteheads.

Inflammatory papules, pustules, nodules, or cysts. Distribution tends to be over the face, chest, back, and shoulders. Post-inflammatory hyperpigmentation or scarring may occur. So you get that skin scarring from after this inflammatory process. And the question stem here is going to describe a teenager with comedones and inflammatory lesions on their face and back. That should be pretty standard. And most of us have gone through this stage and are fairly familiar with it.

So this is an easy one to wrap your head around. This is a clinical diagnosis. There’s obviously no labs here. So, the questions are going to be, I think, about treatment, if I had to guess. Recognizing this should be pretty easy and straightforward, although they’re going to compare it to other things, so it might be difficult there. But for real, it’s the for me, it’s the treatments here. So, for mild, you’re going to topical retinoids and maybe benzoyl peroxide, plus or minus.

Moderate, you’re going to add topical benzoyl peroxide or oral, anti I’m sorry, you’re going to add a topical antibiotic or an oral antibiotic, like doxycycline or minocycline. I’m up early and not reading my notes correctly. We just said topical retinoids and benzoyl peroxide would be for mild and maybe a topical or oral antibiotic for moderate. Severe. This is important and something I kind of missed on my first pass through this. A severe acne isn’t about the number of lesions. It’s about the depth of the lesions or the nodule cystic nature of the lesions.

That’s what severity looks like. And here you’re going to use oral isotretinoin. I think it’s how you pronounce it. You can use, in women, you can use oral contraceptives or spironolactone. And pretty straightforward. If there are comedones it’s going to be acne vulgaris. First-line therapy is going to be topical retinoids.

Isotretinoin is going to be reserved for deep cystic or nodules. And one key I did find was that if you’re using oral antibiotics, it’s a short-term course, and it’s not monotherapy. So there’s a definite pattern to how you prescribe that.

All right, folliculitis is next. This is an infection or inflammation of hair follicles most commonly caused by staph aureus. May be bacterial or fungal or mechanical in origin. Clinical presentation, this again should be pretty obvious. Small erythematous pustules centered on hair follicles. You get mild tenderness or pruritus at the site. Think about where your common locations are.

This shouldn’t be too hard to come up with. It’s going to be in that beard area on the buttocks or the thighs. The question stem is going to be something about these pustules that are centered on hair follicles. I don’t know exactly how they’re going to word that, but you’d think it’d be in there someplace, and it would be after shaving or sweating. So when I came across questions with this, it was in the beard line, or it was someone starting a new exercise routine, something like that. It’s a clinical diagnosis. I guess you could culture it if you really wanted to.

Topical clindamycin will help this. You could use an oral antibiotic if it’s extensive or keeps coming back like doxycycline. And then obviously you’re going to try to do some behavior modifications. So reducing friction, reducing, maybe changing the razor or using some kind of an oil prep before you shave, and adjusting the clothing, all those things. One thing, one other thing to point out here is if you have this with hot tub exposure, what are we thinking? What’s the bug here, not staph aureus all of a sudden? It’s going to be pseudomonas.

Next, we have perioral dermatitis. This is an inflammatory facial eruption surrounding the mouth, often caused or made worse with topical steroid use. So that should be a huge key for you on an exam or in a test question or if a patient walks into the office. If they have small erythematous papules and pustules around their mouth and they either were using or started using a steroid that made it worse or maybe made it better initially and then it flared up worse. You’re talking about perioral dermatitis. One of the other keys here is it spares the vermilion border, so it won’t be on the lips. And there’ll be no comedones, right?

That’s for acne. This is a clinical diagnosis, and obviously the first line treatment is stop any steroids, but it may flare up again after you stop them. You can use topical metronidazole or clindamycin.

Next, we have rosacea. This is a chronic inflammatory disorder affecting the central face, triggered by heat, alcohol, spicy foods, and stress, more common in fair-skinned adults. So another way you’re going to, for me, one of the ways you’re going to pull these apart, rosacea is going to be something more in, it’s not going to be in a teenager. It’s not going to be in a kid, right? It’s going to be in someone probably at least mid-30s, I guess, something in that neighborhood and older, where your acne is going to be obviously in somebody a little bit younger. So you can use those cues. You don’t have to have them, but they definitely help.

So, this is going to be facial flushing and persistent erythema, papules and pustules on the cheeks, nose and forehead. Telangiectasias are commonly present. That’s those little spidery vessels you can see in the skin. No comedones, obviously. Again, that’s going to be a cue for acne. This is also where you can see that that rhinophyma, that bulbous nose in severe cases, especially in males. So what I tend to see in questions is an adult who gets this red facial flushing, which they notice is worse with heat or alcohol.

You don’t have to have the heat and alcohol or spicy food thing in there and or stress, but it’s really helpful. So treatments, again, we’re going to start with behavioral modifications. So if it’s worse with alcohol or heat or spicy foods and it bothers you, then maybe don’t do those things. It’s always a good place to start. Topical metronidazole or azelaic acid, oral doxycycline for inflammatory disease, laser therapy for the telangiectasias. So first line therapy is definitely going to include topical metronidazole remember that and this is think acne without the comedones that’s when you’re thinking rosacea all right that finishes up acneiform eruptions I just want to go through real quick I had it something to think about as these compare to each other. So if comedones are present, you’re thinking acne vulgaris.

No comedones plus flushing and telangiectasias, you’re thinking rosacea. Perioral papules sparing the vermilion border, you’re thinking perioral dermatitis. I’d include probably something in there on steroid use because it’s just such a common issue. And then pustules centered on hair follicles is folliculitis. So what I want you to see from that is how we can take a large group of data and really, really get it down to a handful of words and a handful of ideas. But you obviously have to have a handle on what we’re talking about first, right? I can’t just hand you comedones present equals acne vulgaris.

That’s not going to do it. I can’t just hand you no comedones plus flushing and telangiectasias is rosacea. That won’t help you either. So there’s a balance. You have to understand what we’re talking about first. But once you have a little bit of a handle on it, you don’t have to memorize every single piece in order to get questions right.

Now, it’s nice if you the more you know, the more you know, the better odds you have. But if you’re just trying to keep the forgetting curve away, if you’re just trying to hold on to things, you can break your notes down into these little tiny reminders that bring the whole picture back. So that when you go back to it, you haven’t completely lost everything. So people say, you know, if we’re talking about something like active recall with flashcards, is something I recommend a lot, but with handwritten your own flashcards, and people obviously freak out at that. And they’re like, well, how do you, how do you get through so many cards? How do you write so many? And the answer is I don’t, but I break them down like this until I just made these four, essentially what would be these four cards for this whole section.

Does it give me everything? Absolutely not. It doesn’t give me anywhere near everything, but it’s enough where if I check it back in a week, or in two days. It’ll remind me, and then I’ll have it. That’s not our study tip for today, but it’s a really good one. Papulosquamous disorders is next. This is a group of inflammatory skin conditions defined by papules and plaques with scales.

We have atopic dermatitis, contact dermatitis, drug eruptions, lichen planus, pityriasis rosea, psoriasis, and seborrheic dermatitis to get through. So atopic dermatitis is usually known as eczema. My oldest son had this horribly as a kid, just like he would be crying. It hurts so much. This is a chronic inflammatory skin disease associated with atopy, which is asthma, allergic rhinitis. So, he had a little touch of asthma that’s cleared out. As eczema’s cleared out.

But man, we were we were just lathering him in lotions every day, every night. Had to have special baths for him. Had to have special pay very close attention to the pajamas he was in. And what interesting also was special attention to what we washed his clothes in. So, we’re not on treatments yet, but that’s a nice one, especially in the clinic. You’re not going to get asked about that, I don’t think, on your PANCE. But if you’re in family practice or peds, definitely talk about detergents that the your parents are using.

This is common in children, but can persist into adulthood. Thankfully for him, it has not. It’s triggered by dry skin, cold weather, allergens, irritants, stress, and infection. Definitely, this was worse in the winter. You get that dry air, that dry skin. Absolutely worse in the winter. And then again, those irritants were a major issue.

So, depending on what soaps we used, even in this bath. Clinical presentation. Pruritus is the hallmark. So, you get this itching. Erythematous, red to pink, ill-defined, scaly patches or plaques with dry skin. These are in the flexural surfaces. So, antecubital and popliteal fossa is the most common places you’ll see these.

Or at least that’s where your test questions are definitely going to show up. And in my case of one, that was what I saw. I don’t work in peds. This is just my kids, lichenification with chronic scratching. So they can get really thick and the skin just gets thick. And you can imagine that it took me a while to understand lichenification, but it’s just that constant scratching will thicken up the skin and create that situation. So here again, your stems are going to give you some clues.

Your child is going to have some asthma or something else going on, and usually some kind of change in maybe in detergent, some kind of change in something, maybe not, but it’s going to be itching and scratching on those flexural surfaces. That’s really going to be what you’re going to be looking for here. You’d like to see them mention something about some asthma meds or a visit to the ER or something along the ways that might help clue you into the secondary breadcrumb. Diagnosis is clinical here. A lot of these derm ones in this section are all clinical. First line is going to be emollients and trigger avoidance. So, yeah, we did tons of that.

Topical corticosteroids for flare-ups. You can absolutely use some steroids in bad situations. Antihistamines for the itch or just symptomatic relief. That’s not going to actually help the problem. Severe or refractory. They talked about topical calcineurin inhibitors. I’m not even sure what that is.

I’m just relaying it as stuff I found in my notes. So, on your exam, again, you get that itch, those flexural patches, and atopy, you got atopic dermatitis. Moisturizer, then steroids. Contact dermatitis, this is something else that we’re all, most, I say all, I’m very familiar with growing up where I did. I always think poison ivy as the thing that sticks in my head, although nickel is a good one for people. Things like elastic can be a problem for people if they have elastic waistbands. Can really irritate some individuals.

So this is an inflammatory reaction due to some external exposure. You can have irritant and you can have allergic. Allergic is things like type 4, which is delayed hypersensitivity reaction. It requires prior sensitization. Irritant contact dermatitis is a toxic effect. There’s no immune mechanism. It actually just has a toxic effect on the skin.

Clinical presentation. These are well demarcated erythema, so bright red with vesicles oozing or scaling, often linear or geometric in pattern. To me, I always think of linear, and I think this is why, is because of how they happen, right? If it’s a waistband issue, if it’s the elastic issue, it’s going to be in a linear pattern. If it’s a poison ivy issue, I remember my professor was talking about that it has to do with where your hands go after you’re working. So, you tend to see it on the forehead, on the lower back, that kind of thing, from not from like brushing up against the poison ivy, but from getting it on your hands and then spreading that oil onto specific areas of your skin. Treatment is obviously avoid the offending agent.

Topical corticosteroids will help with this, and an oral steroid if you’re in really bad shape. So, if you have people who have been, you know, I’ve seen this with people outside working, clearing an area, a wooded area that’s filled with poison ivy, they didn’t realize it. Or some people have extreme allergic reactions to it. So, you may need to do oral. So I think I had one, now that I’m thinking about I had a friend in, I think it was middle school, who wound up in the hospital with poison ivy. And I’m going to assume he was getting some serious steroids at that point.

Next, we have drug eruptions. Cutaneous reactions to medications, most commonly, morbilliform, which just means measles like. It looks like measles. Which, if you’ve never seen a case of measles, isn’t all that helpful, I guess. Clinical presentation. It’s a diffuse erythematous maculopapular rash that often starts in the trunk and spreads peripherally. Typically, this and here’s the key, it appears one to two weeks after starting a new drug.

It’s not that day. It’s usually pruritic. And here’s something else I found that I think is really helpful. If there’s no mucosal involvement, think Stevens-Johnson. If you see this, don’t think drug eruptions. Here, the stem is just going to describe a new rash after starting antibiotics or an anticonvulsant. Is something else that they stumbled across.

This is a clinical diagnosis. You’re obviously going to stop the offending medication. Antihistamines for each itch for each antihistamines for itch and topical steroids for should help with this. Lichen planus is immune-mediated inflammatory skin condition associated with hep C. This one always baffled me because these that have very specifics, I just couldn’t keep them straight. So this was the six Ps for the clinical presentation of Lichen planus. This is pruritic, purple to violaceous, polygonal, planar, papules, and plaques with shiny flat-topped surfaces.

Because it has all those words, I jumble it all up in my head. I really can’t keep that kind of thing straight. Even though people use the six Ps to make it easier for them, it’s almost like mnemonics for me. Like I just struggle when you put that many words together. I need mental pictures. And this helps with the mental picture, of course. But if you have that same problem, you are not alone.

This commonly occurs on the wrists and ankles and lower back. You can get Wickham striae, which are fine white lines on lesions. Can get some oral involvement. And here, the question’s probably going to have something about the description of the lesion itself, because it’s different from everything else we’ve talked about today, right? Everything else we’ve talked about has been these erythematous, you know, red kind of plaques or lesions. You know, we’ll get to psoriasis, but that’s that silvery, you know. So you have all these descriptors.

The only one that’s going to be purple and flat-topped is going to be lichen planus. This is a clinical diagnosis. You can biopsy it if you have any questions. Topical steroids. And if it’s really bad, systemic steroids. Pityriasis rosea is a self-limited inflammatory skin condition, likely viral. That’s common in young adults.

Here is where you have your herald patch, followed days later by multiple smaller lesions. So things like herald patch can confuse people. Because herald just means someone who comes before. Someone who comes before or announces things. So, a king would have a herald who would go into the town and tell them that the king was coming right in a day or two or whatever. If you saw the new avengers not avengers Fantastic Four movie with Galactus and the Silver Surfer, the Silver Surfer was described as Galactus’s herald because the Silver Surfer comes before Galactus and announces he’s coming. And that’s what herald means.

So, some of these things, like I like I often use currant jelly stool aren’t helpful, right? Because you don’t know what currant jelly is. So then what does it look like? How does that help me? Remember, it doesn’t help you, right? So having some of these things like a herald patch, if you don’t understand what those terms mean or what that is, it’s not helpful. It just means there’s a lesion that comes first.

After that, you get lesions which follow the skin cleavage lines on the trunk. So that’s where you get that Christmas tree pattern because of the way those lines fall. They’re not going to say Christmas tree pattern on your test, by the way, but it helps to identify it in your mind and build out that picture. You can get some mild itching. In a question stem, you’d really like to have seen probably the Christmas tree pattern and the herald patch to help you figure this one out, because that’s not going to be easy without those. This is self-limiting, so really there’s not much to do besides reassurance. You can use antihistamines or topical steroids if it does get itchy.

But herald patch and Christmas tree pattern should just make you think pityriasis rosea. You should just have that nailed down in your head. And the fact that it’s just self-limited. So I love kind of memorizing groups of things that are self-limited you don’t have to do anything about. I think that’s helpful. Or maybe memorizing treatment groups in general. I kind of think about them like, what are the things I use steroids on?

What are the things I don’t do anything for? Or what are the things I use antibiotics for? Again, different ways to group diseases. You can think about them in multiple different directions in multiple ways. Helps to connect everything together and helps you to hold on to it. We’ve got two left, psoriasis and seborrheic dermatitis for today. Psoriasis is a chronic immune-mediated inflammatory disease associated with arthritis, metabolic syndrome, and cardiovascular risk.

Actually, my brother-in-law has this pretty bad. He’s had it for a very long time. I’m going to talk a little bit as we get down here. Some of his more odd symptoms. There’s a well-demarcated erythematous deep red plaques with thick silvery white scales. Pretty nasty looking. These are on the extensor surfaces.

Elbows and knees, scalp and sacrum. So as opposed to the flexor surfaces of eczema. That’s how I always think about these. I compare them as opposites even though they’re not really. But because of the positioning, it makes it easy to sort of hold that in my head. These have the Auspitz sign, which is pinpoint bleeding when you remove the scale. And you can get nail pitting may also be present.

So your stems here are going to be thick plaques on the extensor surfaces of the elbows and knees with these silvery scales.

Now, the weird symptoms or issues my brother-in-law had, he actually tore his hamstring where they had to go in and surgically repair it twice. He just had it done for the second time. He’s a little older than me. And one of the things they found was psoriasis on the muscle and on the tendon. Really interesting. I had never heard of that before. But they believe that that because he had this strange injury, that that was a causative agent there.

As a clinical diagnosis, you’re going to use topical steroids, vitamin D analogs, phototherapy has been shown to be helpful, and oral steroids when you need to. So silvery scales with extensor surfaces is psoriasis, and it isn’t primarily itchy the way eczema is. It’s an interesting thing to note, but probably helpful on a test. Our last one for today is seborrheic dermatitis. This is a chronic inflammatory condition affecting the sebaceous-rich areas associated with the, here’s one that I’m never going to be able to pronounce, Malassezia yeast. Well, we’re just going to leave it at that. Clinical presentation is a greasy yellow or white scale on an erythematous base with a greasy, flaky appearance.

On the scalp, we know this is dandruff. So, for me, dandruff doesn’t quite cover it, but because we know what dandruff is, it’s a good place to start from. It’s a good place to start your image of this from. You can get in the eyebrows. I’ve seen that. You can get in the nasolabial folds. You can get on the ears.

You can get on the chest. It may be pruritic when it gets bad. Here you’re going to get a flaky scalp or a facial rash around the nose or eyebrows. Generally somebody a little bit older, this isn’t going to happen in a teenager. Seems unlikely anyway. They make antifungal shampoos with ketoconazole or selenium sulfide to help with this. And then low potency topical corticosteroids for flare-ups can be helpful.

But again, this has a lot to do with keeping the area dry, soaps and things. This is a greasy scale on an oily areas so seborrheic dermatitis, dandruff is the mild form. And it will respond to antifungals. Cool.

All right. I just want to run through our study tip for today and then answer our priming questions, and then we’ll be out of here and into the new year.

Fantastic. I hope you’ve got some big things planned. I know I certainly do. Like I was just talking about the review guide. I have, I just came up with a great way to do it a couple of days ago and I’m really, really excited about it. So that’s one of the things I’ve got coming in 2026. The other one, like I said, is hopefully growing the show, growing the audience, helping more students, helping more schools, which is where I’m going to need your help.

Of course, telling people where you’re getting your information from, what’s helpful, what’s a good way to do it, posting it on Instagram, posting it on or you know your school pages where people are asking for help or resources that you use. Like I said, I just it just breaks my heart to hear from people who are struggling and keep buying the same resources over and over, the medical content resources, and then buying the next medical content resource, then buying the next medical, and wondering why it’s not helping when they really just need some direction in their approach and their skills, which we can solve at least a little bit on the show here as we talk about these things, but definitely deeper on the email list and deeper on the 33 Days to Pass the PANCE program. So just looking for a little bit of your help there to let some people know. Anyway, our study tip for today. One of the things I was thinking about is the very first thing I help students solve in the 33 Days to Pass the PANCE program is having too many resources. I struggled initially with building out that program with not including a full review guide, but not including a full video course on medical content. I really wanted to.

And then I thought about it and I was like, you know what, one, I have the podcast already, which is free for everyone. And two, which is how I would explain things anyway. So I’d just be redoing my own work. And then two, everyone shows up with too much information. Everyone shows up with too many resources, too many books. You get these piles and piles of books you’re never going to get through maybe, or two that confuse you because each of them say a slightly different thing. So what I find is people show up with two or three review books.

People show up with multiple question banks. People have multiple YouTube channels. They’ve got Reddit files. They’ve got Anki decks from people. They’ve got free files that someone else made and shared with them. And all of a sudden you have no ability to make a plan or move forward. You have too much information.

You can’t do anything with it. So what I find works best is