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Ep. 28: An Introduction to Psoriasis

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Ep. 28: An Introduction to Psoriasis

Jul 21, 2022

With Psoriasis Awareness Month just a few short weeks away, Skincast hosts Luke Johnson, MD and Michelle Tarbox, MD break down the basics of this skin condition as well as their recommendations for managing it through phototherapy, lifestyle changes, and more.


Dr. Tarbox: Hello, and welcome to "Skincast," the podcast for people who want to learn how to take the very best care of the skin they're in. My name is Michelle Tarbox. I'm an associate professor of dermatology and dermatopathology at Texas Tech University Health Sciences Center in beautiful sunny Lubbock, Texas. And joining me is . . .

Dr. Johnson: Hi, everybody. This is Dr. Luke Johnson. I am a pediatric dermatologist and general dermatologist with the University of Utah in Salt Lake City.

Dr. Tarbox: Today, we're going to talk about a condition that's relatively common and affects a significant proportion of the population when you look at everything writ large. So we're going to talk about psoriasis. Luke, what is psoriasis?

Dr. Johnson: Psoriasis is a red, scaly rash. A lot of things in dermatology are red, scaly rashes. Psoriasis is pretty common though, so you may have seen somebody with it, or I suppose you might have it yourself. It affects 1% to 3% of the population, which means if you pulled 100 people out at random, 1 to 3 of them would have psoriasis.

The red, scaly rash of psoriasis often has thick, white scale over the top of it. And it likes to affect certain parts of the body. It likes the elbows and the knees and the scalp.

Dr. Tarbox: It has two peaks of onset. You probably see one of them more and I probably see the other one more frequently. What is the peak that you see?

Dr. Johnson: So mid to late adolescence/really early young adulthood, psoriasis tends to show up.

Dr. Tarbox: Yeah. And it's one of those conditions that can come up at any point in a person's life, but it is more common at certain ages.

Dr. Johnson: And it just shows up. And then middle age, like in the 50s, is the other time when it tends to arise.

Before I went to medical school, I got psoriasis and cirrhosis confused all the time. So cirrhosis, first of all, is spelled with a C, whereas psoriasis is spelled with a P. Neither of them are spelled with an S at the beginning, which is absurd. Thanks, language. But cirrhosis is a liver disease and psoriasis is the skin disease.

Dr. Tarbox: And I think a lot of the confusion sometimes comes from the fact that many of our medical words originate in the Greek language. So the word psoriasis is actually from a word in Greek that sounds to us now like psora, and then -iasis means condition. So psora means itch or rash that's sort of itchy, and -iasis is a condition.

The term cirrhosis also from the Greek is from the word "kirrhos" in Greek, which is the yellowish color of the skin and the liver that occur in that condition. But they're not really necessarily interrelated with each other.

Dr. Johnson: So, because psoriasis is so common, you might wonder if there are some fancy celebrities out there who have it. And indeed, there are. So just having psoriasis doesn't mean you can't become a celebrity and achieve great things. The following celebrities have psoriasis: Kim Kardashian, Kris Jenner, Cyndi Lauper, Phil Mickelson, the golfer, LeAnn Rimes, Art Garfunkel, Jon Lovitz, and John Updike.

Dr. Tarbox: Also, CariDee English, who was an America's Next Top Model winner, has psoriasis and has been a spokesperson with the National Psoriasis Foundation. And I actually got to meet her and she was so kind and took a picture with me. She's a very sweet person.

But having these celebrity relatable characters that we can kind of illustrate to some of our young patients especially that have psoriasis how full and complete of a life you can have with the condition on the skin is very helpful.

And I think that especially pointing to somebody who's used her position to be more of an advocate for people with the condition like CariDee English really is helpful for young patients.

Dr. Johnson: So what causes psoriasis? Well, there has been a whole bunch of research on that in the last 20 to 25 years, and it is super complicated. Michelle and I look at these medical journals and there are these big diagrams with lots of pictures of cells and arrows going all over the place and a bunch of letters and numbers, and it's just a complete mess. But the good news is that after sorting out some of the mess to some degree, that allows us to develop new medications that impact the causes of psoriasis.

In broad terms, I like to think of psoriasis as an immune dysregulation. The immune system is hanging out in the skin, but it's not doing what it is supposed to.

There are some dermatologists who think that it is autoimmune. I feel like the science has not told us that it is definitely autoimmune yet. It's possible that it will in the future. So I like to refer to it as an immune dysregulation.

Dr. Tarbox: And I think that that's a great way to think about it because the immune cells are activating inflammatory pathways that they're supposed to use to fight bacteria, or viruses, or maybe cancer against normal skin and creating this inflammatory state that then has to be treated.

Dr. Johnson: Well, why do some people get it and some people don't? Why does some people's immune system get dysregulated in this way? We think that there are genes, and there's definitely some genes that have been associated with psoriasis, but like many of the other diseases we talk about, it's not a strict familial inheritance. It's not like if you have it, then your child definitely has it. A lot of times, actually, only one person in the family has it.

And there are certain types of medications that can cause it as well. These are generally medications that your doctor would have prescribed to you for some other reason. But especially in the middle-aged and older age group, if you suddenly develop psoriasis, then I hope that your doctor is looking at your medication list and making sure it wasn't one of those that could have caused it. It can even be a medication that you've been on for a year or two. It's not, "I took this new medication and then suddenly I have psoriasis."

And then kind of vitiligo, which we have also talked about on the podcast, psoriasis can exhibit this Koebnerization phenomenon, again, described by Dr. Heinrich Koebner in the 1800s, which is when a disease goes to sites of injury. So people with psoriasis if they get a big scratch on their leg, for example, they can discover that there is then a line of psoriasis that appears there.

But fear not, there are treatments, and Michelle is super pumped to talk about them.

Dr. Tarbox: So pumped right now. So pumped. The ways that we can treat it . . . Of course, if you have mild psoriasis, knowing Koebnerization, that trauma homing that this condition can do, can kind of worsen the disease, gentle skin care is very helpful.

A lot of times when Americans have a skin condition, we tend to want to try to beat it out of the skin with harsh chemicals. We see this a lot with acne where people will put everything they can find on their skin to try to treat acne, including mouthwash and toothpaste, and sometimes even dish soap and things that are a little bit more harsh.

In general, being more gentle with your skin is almost always the right way to go, and definitely the case here in psoriasis. Of course, there are some topical medications that we sometimes use, both over-the-counter strength topical steroids like hydrocortisone 1% for more minor psoriasis, and then prescription-strength topical steroids with a physician.

Dr. Johnson: Topical, of course, means a cream or an ointment, something you put on top of the skin and then rub in.

Psoriasis is one of the diseases that responds to phototherapy, which we've discussed before on the podcast, a special wavelength of light that can help the skin. In fact, psoriasis is probably the best-studied disease for phototherapy treatment.

And then, again, because the immune system is dysregulated, one option is to just tell the whole immune system to chill out. So we have these immune-suppressing medications that work, but have potential side effects, as you might guess.

As I mentioned, because we're further understanding what we call the pathogenesis of psoriasis, why it happens from a cellular level, new medications have also been developed recently.

Dr. Tarbox: So, in rare circumstances, we can also sometimes treat patients for a coexistent over-colonization with strep with antibiotics to help their psoriasis improve if the strep triggered the condition, which can rarely happen. That's more common with younger patients and more common with much smaller plaques of psoriasis, something we call guttate psoriasis. That word guttate means rain drop-like. And so in that particular condition, we might use oral antibiotics to decrease the strep colonization in those patients.

Now, very importantly, psoriasis is not infectious. It's not contagious in any way. It can occur within many members of one family because of genetic predisposition, but it's not something people pass one person to another. And that's very, very important, especially for patient well-being. I have some patients who've actually been kicked out of public pools or asked to leave daycares because people don't understand the condition and think it might be contagious, but it is not.

Dr. Johnson: And again, with these fancy new medicines, it's very treatable. It's hard for me to overemphasize how great these new medicines are. They're really a triumph of medical and pharmaceutical science. Understanding the way psoriasis works allows pharmaceutical manufacturers to create molecules that interfere very specifically with pathways that have gone wrong in psoriasis.

So we cannot cure the disease. I'm sorry. Perhaps one day we will. But we can give somebody an injection perhaps just every three months, which basically clears their disease with almost no side effects, which is not a cure, but still awfully darn good.

Of course, as you might guess, the main downside of these fancy new medications is how expensive they are. But if you have or know somebody who has significant psoriasis, these are gangbuster medications. And it also gives the whole dermatologic field a lot of hope for some of our other diseases that have been problematic, things like eczema and vitiligo and alopecia areata, that we might also develop similar medications for them.

Dr. Tarbox: There are patient support charities that help people afford the medications to treat their psoriasis when they qualify. So if you're a person who has significant psoriasis and you don't have insurance coverage, or you don't have the financial means to get the medication, you may be able to get it through one of the support foundations.

And then a lot of my patients like to ask me about what kinds of things that they can do with their general health to improve the state of their psoriasis. And I love when they ask that question because our general state of health significantly influences the course of psoriasis, and modifications to our diet and behavior can help improve the condition and its response to treatment.

So we know for a fact that psoriasis is a pro-inflammatory condition. Things that we eat or take into our body that cause more inflammation can worsen psoriasis, so highly processed foods, foods with a lot of sugar in them. Alcohol we know is one of the things that can push on psoriasis, as can smoking.

Patients who have psoriasis that are more active and who stick with a healthier diet have an easier time controlling their disease and have less extensive disease.

Now, we know that the psoriasis can make it hard to have a healthy lifestyle. The psoriasis plaques can make it harder to exercise sometimes. If you are a person who's uncomfortable showing the skin that has psoriasis on it, there may be some activity limitation because of the need to cover.

However, the skin of psoriasis is, besides the inflammation, normal skin. It's not any more likely than your normal skin to get infected. Actually, it may be less likely to get a skin infection than your normal skin. And it's not something you're going to pass to anybody else. So letting that skin be open to the air is not a damaging thing at all and is not going to put you or anybody else at any kind of danger.

But I do always encourage my patients who have psoriasis to try to be as healthy as possible. We also know that things that are anti-inflammatory like turmeric can help that. We know that some studies have actually looked into the addition of other supplements like ox-bile supplements to help improve the metabolism of certain fats in the gut.

But what are some things that patients need to worry about with psoriasis, Luke?

Dr. Johnson: Well, all of those lifestyle factors are a good idea because we know that psoriasis is associated with an increased risk of cardiovascular disease, things like heart attacks and strokes and so on. So somebody with psoriasis compared to somebody who's exactly the same, same weight, same blood pressure, same exercise level, and everything, if those two people are compared, the person with psoriasis has a greater risk of developing something like a heart attack or a stroke. It's a bummer, but it's true.

So people with psoriasis, I always encourage them to . . . It's an extra reason to stay on top of your blood pressure and your cholesterol and have a healthy activity level and a healthy weight and stay plugged in with your primary care physician and so on.

Good news is that this one and a lot of the other things that we know can also occur in people with psoriasis. The worse your psoriasis, the worse that association. So if you have really mild psoriasis, your increased risk of cardiovascular disease is probably really small.

Also, treating your psoriasis appropriately, perhaps with some of these new medicines that I mentioned, also reduces that risk. So make sure you get plugged in to a dermatologist or somebody else comfortable treating psoriasis.

People with psoriasis also get an increased risk of arthritis. There's a particular type of arthritis called psoriatic arthritis. So if you or somebody you know has psoriasis and get new joint pains, especially if you don't think they're sort of normal for your level of activity, especially if they're worse in the morning and associated with stiffness, definitely want to tell somebody about that.

Dr. Tarbox: And also, patients who have psoriasis are at a greater risk for both anxiety and depression, which is completely understandable given the fact that there can be some social isolation caused by people misunderstanding the condition or by a person's concern about being perceived differently when they go in public. So we do want to always screen our patients that have psoriasis for depression or anxiety.

And if that's a part of your condition that's affecting your life, definitely bring it up with your physician, because treating those mood disorders can help improve your overall state of health and then make the condition easier to manage.

Dr. Johnson: Unfortunately, there are a number of other health conditions that are also associated with psoriasis. I think the ones we mentioned are the most important, but I like to think that this emphasizes the importance of getting plugged in to good medical care and knowing that we have a lot of really great treatments for psoriasis these days.

Dr. Tarbox: Well, we want to thank you guys so much for listening today and learning more about psoriasis. Luke, I think you have some special thanks.

Dr. Johnson: Of course. I always have special thanks for the University of Utah for supporting the podcast and to Texas Tech for lending us Michelle.

You can find all of our "Skincast" episodes on Apple Podcasts or wherever you get them. And you can also find all of our other podcast, which is called "Dermasphere." Michelle, you want to talk to them about "Dermasphere"?

Dr. Tarbox: For sure. "Dermasphere," as we put it, is the podcast for dermatologists by dermatologists and for the dermatologically curious. It's about an hour long or so. It's longer than our "Skincast" episodes. And we discuss in more depth some of the conditions that we treat as dermatologists, some of the upcoming evidence and new treatments for different kinds of conditions, as well as some of the new technologies that will help us take better care of our patients.

Dr. Johnson: So if you like to nerd out about dermatology like we do, come check us out there. Otherwise, we'll see you next time right here on "Skincast."