Psoriasis: Overview of Psoriasis
Guest: Dr. Bruce Thiers – Dermatology, MUSC
Host: Dr. Linda Austin – Psychiatry, MUSC
Dr. Linda Austin: I’m Dr. Linda Austin. I’m talking, today, with Dr. Bruce Thiers, Professor and Chair of Dermatology at the Medical University of South Carolina. Dr. Thiers, I know you have a broad range of interests, but let’s focus, right now, on psoriasis. Dr. Thiers, what is psoriasis?
Dr. Bruce Thiers: Linda, right now, we think of psoriasis as a disease in which the skin is simply growing too fast.
Dr. Linda Austin: So, what does the rash of psoriasis actually look like?
Dr. Bruce Thiers: Well, when you look at the skin of somebody who has psoriasis, the first thing you usually notice is that they have some very well demarcated areas where the skin is very white and scaly. And the scaliness, again, is simply a clinical sign that the skin is growing at too rapid a pace. Most of our treatments for psoriasis, therefore, are designed to try to get the skin to slow down and not grow as quickly.
Dr. Linda Austin: So, I think most of us know that skin regenerates itself and sloughs off in flakes. So, in other words, in psoriases, that’s happening too quickly, and so all the flakes are kind of piling up and sticking together to get that look? Is that right?
Dr. Bruce Thiers: That’s basically correct. The skin is in layers, with the epidermis being the most outer layer, and the dermis being the layer right below the epidermis. The epidermis itself is composed of several layers of cells which regenerate every two weeks or so. However, this regeneration time is much quicker in psoriasis, and that’s why the skin builds up.
Dr. Linda Austin: What triggers that? Is that known?
Dr. Bruce Thiers: The cause of psoriasis is unknown. I can tell you that millions of dollars have been spent over the past several years trying to discover the cause of psoriasis. And, in my career in dermatology, which is now approximately 30 years, I can think of, probably, half a dozen theories that have come and gone in terms of the cause of the disease. Right now, most physicians believe that psoriasis is actually caused by some derangement in the immune system.
Dr. Linda Austin: What’s the earliest age that psoriasis can start?
Dr. Bruce Thiers: Well, psoriasis can occur in infants. Some children who have diaper dermatitis go on to have psoriasis when they’re older, and we think the diaper dermatitis in these children is, really, an early manifestation of psoriasis.
Dr. Linda Austin: Is it commonly triggered, as other autoimmune diseases often are, by stress, or by some other illness, or does it just come out of the blue?
Dr. Bruce Thiers: That’s a very good question. We often think of stress as an exacerbating factor in psoriasis, but not the primary cause. Many patients who are under stress notice that their psoriasis gets worse, or they can have their first bout of psoriasis after a stressful event. Similarly, especially in teenagers, psoriasis can come on after a strep throat. So, in reference to your question, yes, infectious diseases can trigger psoriasis as well.
Dr. Linda Austin: That’s very interesting, because strep throat can certainly set up autoimmune responses. And some people think, even for psychiatric illness, that the antibodies attack different organ systems of the body.
Dr. Bruce Thiers: Well, one thing about skin disease is that the cause of many conditions that we see in dermatology is unknown, and we tend to think that, perhaps, there’s some unexplained infectious factor; bacterial or viral, that sets them off.
Dr. Linda Austin: How bad can psoriasis get?
Dr. Bruce Thiers: Well, back in the 60s and 70s, there was a tendency for many advertisers to trivialize psoriasis and talk about cures that they had, or treatments they had, for what they called the heartbreak of psoriasis. But now we know that psoriasis can be more than just a nuisance, that it can be even a life-threatening condition. Psoriasis can involve very limited areas of skin. And, in its most limited areas, it can involve just the elbows, the knees. Another common area is the genitalia, or the scalp. In its most severe expression, psoriasis can involve every inch of skin, and other organs; such as the joints.
Dr. Linda Austin: If it becomes life-threatening, how does that happen?
Dr. Bruce Thiers: Life-threatening psoriasis is simply an extension of limited psoriasis. It’s just, presumably, a more severe derangement in the immune system that affects not only limited areas of skin, but more generalized areas of skin. And that also affects the treatment that we recommend. For limited psoriasis, topical therapy, such as creams or ointments, is usually the treatment of choice. When somebody has more extensive psoriasis, we need systemic therapy, which means either oral medicines; pills, or injected medicines.
Dr. Linda Austin: Now, those creams and ointments, are they medicated themselves, or are they simply to soften and moisten the skin?
Dr. Bruce Thiers: No. The ointments are medications. Most commonly, we use topical steroids. You know, people think of steroids as being menacing and evil, but in reality, steroids are very potent drugs that can temper the immune system. We can put them in ointments. Many of the treatments we use for limited psoriasis are topical steroid ointments. There are also ointments that contain drugs other than topical steroids.
When we treat psoriasis with systemic medications; injected medications or oral medications, we tend to use nonsteroidal preparations. We know from experience, when we give steroids by mouth for psoriasis, the psoriasis often gets better. But, when the steroids are stopped, the psoriasis often flares even worse than it was to begin with.
Dr. Linda Austin: And, of course, long-term use of steroids poses other problems. You may get rid of the psoriasis, but cause a host of other health problems.
Dr. Bruce Thiers: Right. Steroids, when given orally or by injection, cause a lot of long-term problems such as softening of the bones, water retention, high blood pressure, diabetes, etc. But I’d also caution that many of the other drugs we give systemically for psoriasis can cause long-term problems as well, which may not be as severe as those caused by steroids, but they also need to be respected.
Dr. Linda Austin: Are there rough numbers as to what percentage of patients with psoriasis you’re able to help versus those who are more treatment resistant?
Dr. Bruce Thiers: Psoriasis, in my opinion, can be helped in virtually every patient. There’s a very small percentage of patients that is resistant to almost all treatments. But, almost every patient we see, we can help. Now, that doesn’t mean we can totally clear psoriasis in all patients, but we can certainly help just about everybody that we see.
Dr. Linda Austin: Boy, that’s encouraging news.
Dr. Bruce Thiers: Especially with the new drugs that have come to market in the past several years, many patients who previously could not be helped are helped. So, there are a lot of new treatments for psoriasis. And, again, we can find something to help almost every patient that we see.
Dr. Linda Austin: Oh, that’s really exciting. Does it tend to be a life-long condition, or does it every spontaneously just disappear?
Dr. Bruce Thiers: Well, psoriasis is one of those strange conditions. I mentioned earlier that we can see it infants, and in other patients, it doesn’t start until 50, 60, 70, or even 80 years of age. So, the question that comes to mind is, why, all of a sudden, later in life, do some patients develop psoriasis? Conversely, there are patients that battle psoriasis for years and years, and decades and decades, and all of a sudden, they go into spontaneous remission and never have any further problems with the disease. Even though in the past several years we’ve learned a lot about psoriasis, there’s still a lot more that we need to know.
Dr. Linda Austin: Is there a national society or association for people who suffer from psoriasis?
Dr. Bruce Thiers: The best resource for patients with psoriasis is the National Psoriasis Foundation. Their website is www.psoriasis.org.
Dr. Linda Austin: Do we have any active research going on here at MUSC?
Dr. Bruce Thiers: We’re not doing any basic science research at MUSC on psoriasis, but we have access to all the new drugs. All of our patients have access to these drugs as well.
Dr. Linda Austin: Are those drugs in clinical trial or FDA approved?
Dr. Bruce Thiers: Most of these drugs are FDA approved. There are always new drugs going into clinical trials. And, again, if a patient needs these drugs, we can have access to them.
Dr. Linda Austin: Dr. Thiers, thanks so much for talking with us.
Dr. Bruce Thiers: My pleasure.
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