Derm-it Trotter! Don't Swear About Skincare.
Feeling frustrated or overwhelmed with everything skin? Does the skinformation overload make you want to swear about skincare? Join Dr. Shannon C. Trotter, board certified dermatologist, as she talks with fellow dermatologists and colleagues in skincare to help separate fact from fiction and simplify the world of skin. After listening, you won’t swear about skincare anymore!
Derm-it Trotter! Don't Swear About Skincare.
Feeding the Fire: Fat, Inflammation, & Psoriasis
What if the most inflammatory driver of psoriasis isn’t on the skin at all, but deep in visceral fat? We sit down with Dr. James Song to unpack how adipose tissue acts like a hormone-secreting organ, releasing cytokines that can fuel psoriasis and psoriatic arthritis. From the brain’s weight “set point” to genetics linking obesity and psoriasis risk, we reframe weight as biology—not a moral failing—and explain why that matters for treatment.
We break down fat types, the cytokine cascade connecting metabolic health to skin disease, and what GLP-1 and GLP-1/GIP therapies may be doing beyond weight loss. The conversation also tackles biologic response in higher BMI patients, emerging combo trials, and real-world issues like access, cost, and compounded medications—ending with a practical, whole-system roadmap that protects both skin and heart health.
Thank you Eli Lilly for sponsoring this episode.
This podcast is sponsored by Eli Lilly. Weight is really determined by a certain part of our brain called a hypothalamus that has a set we call it a set point. And that is genetically determined, but there are also other factors like stress levels, the amount of sleep that you're getting, certain medications that could affect that set point as well. We now know that patients with psoriasis have about a 50% higher risk of having cardiovascular disease. Patients who have higher BMIs tend to have more severe disease. And with more higher BMI, it's generally harder to treat.
SPEAKER_00:Welcome to Dermot Trotter, Don't Swear About Skin Care, where host Dr. Shannon C. Trotter, a board-certified dermatologist, sits down with fellow dermatologists and skincare experts to separate fact from fiction and simplify skincare. Let's get started.
SPEAKER_02:Welcome to the Dermot Trotter Don't Swear About Skin Care podcast. I'm with Dr. James Song. He's a board-certified dermatologist and director of clinical research and serves as the chief medical officer for Frontier Dermatology. And we're here today to talk about psoriasis and obesity and the connection that exists between the two. I think that a lot of people you're going to be shocked about sort of what we've learned and where we can go from here. But I want to welcome you to the podcast. It's great to have you on here, Dr. Song.
SPEAKER_01:Hi Shannon, thank you so much for having me. I've been following you for quite some time now, and I always was looking forward to the opportunity to be a part of this. So I thank you for making one of my dreams come true.
SPEAKER_02:Well, always happy to please. And really excited to have you here too, because we know psoriasis is a passion of yours and definitely very engaged, obviously, in research and treating patients and even at the foundation level. So I wanted to tackle, you know, this idea of psoriasis and obesity because I think a lot of people, you know, really aren't familiar with the connection. They don't realize that, oh, you know, that there is a connection in the first place. And, you know, just talking about when we think about ourselves, you know, all of us look at ourselves and probably complain or think, gosh, I could lose a few pounds or I'm a little overweight. And not even knowing that when we look at fat in the body, that there are different types of fat. So I wanted to talk a little bit more about that, see if we can walk our audience through those different types and do they have a real role in the body too? Because I think a lot of people just think that's just hanging out. It's not doing much of anything.
SPEAKER_01:Yeah, yeah. It's a great question, Shannon. Yeah, I think when most people think about fat, they think about it like stuffing, you know? It's just excess calories that you're not burning. So you're kind of just sitting there. That's not entirely true, though. We do know there's several different types of fat, depending on where the fat is on the body, they have several different functions. It could be actually beneficial to a certain degree, uh, but also harmful. And we'll kind of just touch a little bit on that. I think for most people, when they think fat, they think about the skin that you could pinch, right? And that's what we call subcutaneous fat. And for the most part, that's pretty harmless. It doesn't really do anything bad. It's really the fat that's around our belly and our kind of, we call it our viscera, we call that visceral fat. That's the dangerous fat. That's the one that we know is kind of like a like a chemical factory that is just pouring out what we call cytokines. We'll get into that later. These are kind of messages to the rest of our immune system to kind of overreact. But that's really the main reservoir of those kind of harmful cytokines that contribute to a lot of the diseases that we treat in dermatology. And just to kind of round that out, Shannon, we have what we call brown fat. That is what we see more in infants, where you actually burn those calories to generate heat and then kind of goes away as we get older. But interestingly, um, for people who exercise and do like cold plunges, that's kind of, you know, all the craze now. There is some data to suggest it increases the brown fat. But as we get older and gain more fat, that good brown fat actually goes down as well. So I think it's just important that not all fat is created equal. But also when you look at somebody of different ethnic racial backgrounds, you know, Asians, I'm going to use an example. A lot of a lot of us look thin. We have, you know, low subcutaneous fat, but actually we have a good amount of visceral fat. And that's really the fat that's bad for you.
SPEAKER_02:Very interesting. Because I I think, you know, when people think of fat, they just think of fat, right? And like you mentioned, it's just sort of hanging out and not really active in the body. And what we've learned over time is you mentioned with the different roles, you know, that lovely pinchable fat, which I can get enough on my waist here that keeps us warm and helps with that temperature regulation. And then having, you know, a role of the body where visceral fat serves a little bit of a role that's in a positive way, but obviously too much of it, not so great for us. Let's talk about where that kind of goes wrong and sort of what's happening with fat, where again, I think people think it's just kind of dormant, it's hanging out. How is fat really metabolically active? Like what is it doing just hanging out in the body?
SPEAKER_01:Yeah, I think it's best to think about fat or what we call dipocytes as a like a biologically active like endocrine system. I mean, that's really what it is. It's an organ that spews out various different messages to the rest of our body. On the one hand, fat is good because there are certain hormones we call leptin that once you eat, it tells you that you are full, right? So it tells it's a satiety signal. But it also is a very pro-inflammatory signal as well. It actually increases certain cytokines like T817, for example. But in addition to that, there are other pro-inflammatory cytokines like TNF alpha, IO1, IO6. I mentioned T817. And if they sound familiar, they should, because these are the same cytokines that cause a lot of the autoimmune disorders that we treat, whether that's psoriasis and psoriatic arthritis. And so it's not a surprise that if you have this major source of inflammation, patients who are obese tend to be at higher risk of developing certain conditions, such as psoriasis and psoriatic arthritis.
SPEAKER_02:Wow, and and that's, you know, I think where it gets a little confusing, right, for people to understand that it's truly, like you said, a part of that endocrine system, really being metabolically active and contributing potentially to inflammation in different disease states like psoriasis. You know, when we think about, you know, somebody who is overweight or obese, one of the things that always, you know, bothers me is we tend to be judgmental, right? We automatically look at these people and think, oh, you know, it's a lack of willpower. You're just not able to control yourself if you've got a bag of Doritos in front of you. And I really try to get people to understand, you know, it's really not that simple. I mean, we all have our cravings, right? We love our midnight runs, and people do that to Taco Bell, you see the line out the door, or somebody has, you know, their chips they love, or they may not exercise as much as they want to or need to. But, you know, I think the idea of obesity, what we need to change in our mindset is this is really more of a complex disease state. When we're overweight or we have excess fat, this is something that it's multifactorial and a lot of things contribute to that. How do you walk patients through understanding that this isn't just a lack of willpower, but sort of a combination of several complex factors that actually contribute to them being overweight or obese?
SPEAKER_01:It's such an important point, Shannon, because I think until we start to think differently and frame it differently, we're not going to make any progress in this area. Um, to your point, a lot of times patients are told it's a character flaw. They don't have willpower, right? And they need to try harder and take care of themselves, and this all goes away. And we know that so much of this is genetic. Uh, we know that weight is really determined by a certain part of our brain called a hypothalamus that has a, we call it a set point. And that is genetically determined, but there are also other factors like stress levels, um, the amount of sleep that you're getting, certain medications that could affect that set point as well. But you could try your darn best to eat better, exercise. And what does your set point do? It tells you to be even more hungry. It turns, it tells your metabolism to slow down, right? Because it is trying to, it's like a thermostat. So until we can adjust that set point, it's very, very difficult. And, you know, this isn't that different than someone with high blood pressure, right? If someone has blood pressure problems, you'd be like, hey, diet and exercise first. And if that doesn't work, then we're gonna put you on medical therapy. And we're not gonna make people feel bad about not doing enough diet and exercise to get your blood pressure under control. Why are we thinking about obesity any differently? I mean, it's a disease. And so we should be thinking about it in the same way of hypertension, hyperlipidemia, and diabetes. And that's why we call this kind of metabolic syndrome.
SPEAKER_02:Really good point. Because I think for a lot of patients, they put it on themselves. There's a lot of shame, you know, embarrassment. And I think even as you know, dermatologists, we can kind of admit to ourselves, I think sometimes, you know, you have a little you know, bias sometimes or when you see people and just really changing that set point and making us all realize, you know, like you said, this is a disease like anything else. Why would we treat it any differently? Unfortunately, I think a lot of you know those cultural norms kind of infiltrate into our thoughts or, you know, our ideas of what we were sort of told about, you know, being overweight or obese, you know, truly what it is when we now understand, you know, it's much more complex. I think even over that hurdle, you know, as the dermatologist or healthcare provider, and then also for patients to embrace that and understand that we are here to help, you know, and beyond yes, diet and exercise are essential, but there are ways to kind of build on that and really help them through that process because it's going to impact their overall health. But I know from our standpoint, we're also obviously looking at the skin health. And then specifically, you know, in certain disease states, we know hijodenitis separativa, we know psoriasis, like these are impacted. In particular, psoriasis, I think, is a lot of interest to our listeners that have reached out and said, you know, we see this craze about talking about now weight and the psoriasis connection. So I I wanted to go back and kind of visit your thoughts on this connection, sort of what you've seen over your career and in the latest, you know, data coming out, and how we understand that connection to actually really exist between the two.
SPEAKER_01:Yeah, yeah. So as we uh said, you know, we know psoriasis or excuse me, obesity can increase one's risk of psoriasis. There's no question. And the same is true for psoriatic arthritis, and that connection or relationship may be even stronger with the latter. A lot of times we have a hard time separating out is it the actual obesity that leads to psoriasis or are there other confounding factors? Um, but there's been actually a number of really well done, what we call Mendelian randomization studies, where you look at genetic variants that predispose somebody to obesity, and then you follow those people who have those genes and see who gets psoriasis. And that really controls for a lot of the confounding variables. You're really just looking at genetics here. And we're seeing up to a two-fold higher risk of developing psoriasis or psoriatic arthritis if you are obese for many of the reasons that we talked about. You have this big chemical factory that's pouring out these cytokines that we know can cause psoriasis and psoriatic arthritis. Anecdotally, what we've seen, at least in case reports and now larger case series, is that patients who have both psoriasis and type 2 diabetes, they go on a treatment for their diabetes, right? Specifically, a we call it a GLP1 receptor agonist or a GLP1 with a GIP, so it's a kind of a combo therapy. And without any psoriasis therapies at all, not only do their weight go down, not only does their diabetes improve, but their skin clears as well. And I think that was the first signal that there is something here to it. Now the question, Shannon, is is it the weight loss itself that actually leads to the psoriasis improvement? Because we've seen other studies where hypocaloric diets, bariatric surgery, or any other type of lifestyle intervention that reduces the weight can also indirectly improve psoriasis. So there probably is something to that. But what is interesting is that these patients are also clearing their skin even before they have any meaningful change in their weight, which makes us wonder is there a direct effect with these weight loss medications that we see on the inflammatory component of psoriasis? And the answer to that probably is yes. And we have some what we call in vitro data, which isn't human data, but some of the in vitro data suggests that GLP1s can actually modulate the immune system in such a way where it decreases cytokine signaling, immune cell trafficking. Some of the cytokines that we talked about before, like TNF and L17, they come down even independent of weight. So I think it's a really kind of fascinating and exciting area of research how we can use weight loss medications that improve inflammatory disorders independently of the weight loss.
SPEAKER_02:So if I was your psoriasis patient and came to you and I, you know, saw that a little blurb, you know, maybe on my Yahoo news and you know, that this is happening and I have psoriasis, how would you approach that with me if you know I am overweight or obese, have psorias to say, hey, Dr. Song, I want to go on a GLP1? Is it that simple or is it a more complex conversation to talk about?
SPEAKER_01:Yeah, I think as with all things, you know, benefit versus risk, right? And I think people often focus so much on their risks, which is understandable, right? Safety is important, but we don't talk enough about not treating or under-treating the disease and what are the downstream consequences of having not just psoriasis, but also the meta the um the comorbidities associated with psoriasis as well. We now know that patients with psoriasis have about a 50% higher risk of having cardiovascular disease. Okay, and that's independent of traditional risk factors. So you take the hypertension, the lipids, the cholesterol, and the weight out, they still have about a 50% higher risk. And this leads to about a five-year decrease in life expectancy. So I start with that. And while the weight loss is great and all, and it's gonna help, I think, with not just with the weight, the diabetes, and the psoriasis, we now have data. It's actually on the label, Shannon, for several of our semaglutides, illyroglutides, that it actually lowers mace risk. I mean, that's on the label. It decreases heart attacks, strokes, all cause cardiovascular death. Um, I just got back from the EADV in Paris, and there was a very, very powerful podium presentation about people who use GLP1s and glyphosis versus non-GLP1 diabetes medications, not only do they live longer, their risk of anxiety and depression goes down. Their use of substances like illicit drugs and alcohol goes significantly down too. So I try to bring in all the positive benefits, even outside of the skin, of using these types of medications. So absolutely, if you qualify for a GLP1, right, you've done all the lifestyle changes that we talked about, which isn't easy, but you've done it, and you meet the eligibility criteria, which is fairly simple. It's you have a BMI of 30 or greater, or a BMI of 27 or greater, but you have one weight-related comorbidity. So blood pressure, diabetes, cholesterol, sleep apnea, cardiovascular disease. Then, yes, absolutely, this is something that we bring up. The question, though, Shannon, is you know, you have a five to 10 minute visit for these patients. We don't have teams of biological coordinators that can do these medications or push these medicines for us. Do how do we have the time and the resources to do all these things? And I I would be lying if I said I have it figured out. You know, I do this enough and I'm fortunate enough to be in a bigger practice where we have those means to do that. But I certainly want to uh I empathize with our colleagues who may push back and say, I just don't have the time or resources to do that. At least what I would say to those people would be that at least have the conversation, make that connection, and then if a patient is interested, at least try to refer them to someone that actually can help get them on these steps and medications.
SPEAKER_02:Well, very powerful what you mentioned about in the label, because I think that would shock you know a lot of our listeners out there that might be on one of these medications and not even know the benefit, regardless if they have psoriasis or another condition or not, and even some of our healthcare providers on the power that I can offer for patients and being potentially cardioprotective. That's pretty amazing. And for dermatology, you're right, it is tough, you know, in the environment that we work in, but also the opportunity to collaborate with our colleagues in the primary care space to make that happen for patients, just knowing there's that benefit. I think there's an opportunity there, you know, to offer it to patients. Do you feel like based on maybe what we know with some of that data or what we're looking at probably going forward and what's in clinical trials, do you think for management of psoriasis that it's sort of a you know monotherapy where you just go on a GLP1 or a GIF one, or maybe you're going to actually, you know, combine it? Or what are your thoughts might might be the ideal strategy on what we might do?
SPEAKER_01:Well, we do have one study that is ongoing, actually, two in parallel. It's called a together psoriasis or the together psoriatic arthritis studies. And this is looking at uh ixychizimab, which is an IL-17A inhibitor, very effective for psoriasis. And you are combining that with terzepatide, which is a dual GLP1 and GIP inhibitor, versus those who just get ixychizimab alone. So you want to see, is there an additive benefit or a synergistic benefit of combining these therapies? We should be getting the top-line data here probably sometime in later 2026, I believe. But that is the way that it is being studied. Um, and and I do believe that that's the best way is to use them as combination or adjunctive therapy versus just monotherapy alone. Although I will say, Shannon, if you have very mild psoriasis, so just a couple little plaques here and there, and you have the comorbidities that qualify you for getting onto one of these medicines, you may be able to just go on monotherapy alone, right? And then one thing, you know, I didn't mention here, I think it's important, is that patients who have higher BMIs tend to have more severe disease. And what more higher BMI, it's generally harder to treat. Even though we have really effective medicines now in psoriasis, the heavier you are, the medicines just don't work quite as well. We see a much bigger drop-off with our older medicines, like TNF inhibitors, but even our newer ones, like IL-17 or IL-23 inhibitors, you do start to see a drop-off in patients who get beyond 250 pounds, which is why some of these medicines are weight-based. And I think those medicines might be better for the heavier patients because standard dosing doesn't work for everybody. But the biggest kind of, I think, data point here that's important is that when you looked at Ixy Kizimab in their phase three studies, Shannon, and you looked at PAS C100, that's 100% clear, the difference of being less than 25 BMI versus 40 BMI or greater was profound. We're talking about a 20% plus difference in the likelihood of getting to 100% clear. So about a two-fold difference. And this was the same with psoriatic arthritis. When we look at minimal disease activity, which is a very high bar, very low levels of disease activity in your joints and your skin, you're still twice as likely to get to that high bar if you were under a BMI of 25 versus over 40. So that makes a lot of sense then why using a GLP1 in addition to Kismab may provide additional benefits for these patients.
SPEAKER_02:I know you and I are familiar with BMI. Do you mind commenting on BMI how that's sort of calculated? Because for some area listeners, I think I've heard of that, but I really don't know what it means, but I've been told I have a very high one.
SPEAKER_01:And yep, yep. So BMI is just one way of measuring weight, right? Or obesity. Um it's not perfect. So the way we calculate it, we take your weight in kilograms and divide it by your height in meters squared, and you get a number. Um, let's say a 25 might mean that you're overweight. A number over 30 means you're obese. Over 40, you're severely obese. That's a really kind of it's an imperfect way of measuring um fat, but it's kind of probably the simplest way of doing it. Uh, we know that there are people out there that have who are very, very muscular and athletic and they can have very high BMIs, right? You look at the rock, right? Dwayne Johnson, the guy is ripped and shredded. I think he's like 6'2 or 6'3 and weighs like upper 200 pounds. You do the math, he he is severely obese, right? Right. No one will say that to him, right? Not in front of his face, but even still objectively, he is very, very good shape, right? Muscular. But it just goes to show that BMI actually overestimates um the score in muscular individuals. And there are a lot of other examples of that as well. There's other ways to measure uh body fat, though. You know, there's DEXA scans, which are like X-rays that look at the density of bone, muscle, uh fat. There's um impedance tests where you could just hold on to something. It sends electrical currents, you could do caliper studies. So there's a lot of different ways to do it. BMI is just kind of our quick and dirty way of measuring uh the fat levels, which again is not perfect.
SPEAKER_02:But you're right, it gives us a really good gauge, at least to work from from now. And maybe we'll improve upon that, you know, as a metric as we kind of go forward and classify, you know, patients a little bit better, you know, regarding their weight. But you're right, it's the best thing we've kind of got now, although imperfect. So if somebody's out there listening, you know, in the last few minutes we're having, they're thinking, you've kind of sold me on this. You know, I've I've got psoriasis, I'm worried about my risk factors. They may or may not, you know, have diabetes already, or one of the other, you know, risk factors are comorbidities like high blood pressure or cholesterol. What would you say to them as potentially, you know, a reason maybe you wouldn't consider doing it? And then if it was, you know, meant for them, how would you move forward with that?
SPEAKER_01:Yeah, the the biggest barrier, Shannon, is going to be cost and access. There's no question these are expensive medications, but I would argue that the cost of not treating is even more expensive, right? Because we're just you're just delaying the inevitable and having to get an open heart surgery or some other major medical intervention will cost a lot more money. But that's the main barrier, right? And then the the natural question that comes up is if I can get insurance to pay for it, what about compounded medications, right? And I think this is a conversation for another day, but you you really have to be careful of what you're getting with compounded medications. I understand it's cheaper, but you don't always know what you're getting there. If you have diabetes or obesity, and you as an office, as a dermatology practitioner, just don't know how to do it or don't have the means to do it, at least refer them to somebody, whether it's a primary care doctor or an endocrinologist that can really do the heavy uh work to get disapproved, because truly these are life-changing drugs. And I think that we are doing a disservice to our patients if we don't at least bring it up to them.
SPEAKER_02:And and I think too, patients out there now are going to be asking about it, you know, listening to this, just seeing that there's value and you know, looking at, you know, being overweight or obese is more than we talked about, that lack of willpower. Hopefully, for you know, the dermatologists and providers listening out there that they're thinking, you know what, I should probably be approaching my patient maybe a bit more holistically. I think that's a shift we're going to see in dermatology as a whole as we look at a lot of our skin conditions as, you know, more so systemic inflammation. We've known this for years, but now that we have opportunities to treat it, I think it's going to shift. It's interesting. I think, you know, we used to have the internal med and then Durham model. I don't see us going back to that paradigm for training, but boy, is it going to be integrated more into how we manage patients? Yes.
SPEAKER_01:Yes, yes, yes.
SPEAKER_02:Well, I want to thank you so much for coming on and kind of going over this. You know, I know it's succinct, but this gives people really a taste, I think, for listeners of understanding, you know, that how complex, you know, obesity can be and then link, you know, to psoriasis and other inflammatory disease and skin that um we'll obviously touch upon in the future. But thank you so much for sharing your expertise with us today.
SPEAKER_01:Shannon, it's my pleasure. Thank you for having me.
SPEAKER_02:For our listeners that want to track you down online, how can they find you?
SPEAKER_01:Uh, my Instagram handle is E as an Edward, J as in James and song, like singing a song 812. And then it's the same one on LinkedIn. So I try to be active, not nearly as active as you, Shannon. I need to up my social media game, but um, yes, you can find me on there.
SPEAKER_02:Well, thank you for sharing. I'm sure some people will check it out. And stay tuned for the next episode of Dermotrotter Don't Swear About Skincare.
SPEAKER_00:Thanks for listening to Dermotter. For more about skincare, visit dermittrotter.com. Don't forget to subscribe, leave a review, and share this podcast with anyone who needs a little skincare sanity. Until next time, stay skin smart.
