Mark Lebwohl, MD: Hello, I’m Mark Lebwohl. I’m at the Icahn School of Medicine at Mount Sinai in New York, New York. I am joined today by Dr Philip Mease, from the University of Washington School of Medicine and Swedish Medical Center/Providence St Joseph Health, in Seattle, Washington, to discuss management of plaque psoriasis and the importance of a multidisciplinary approach in treating this disease state.
Welcome, everyone. Let’s begin. Phil, let’s discuss together the clinical manifestations of plaque psoriasis and psoriatic arthritis. I’ll start with plaque psoriasis, which as you know, is characterized by sharply demarcated, erythematous, scaling plaques. In fact, I teach my residents that if they can say the words sharply demarcated, red, scaling plaques, then that’s the diagnosis. Often patients will present it with that manifestation on just 1 area, like the glans of the penis, for example. The diagnosis is missed all the time when it’s not on the elbows and knees, not on the scalp, which are the classic locations. But when you can say those words, think of psoriasis. Tell us about the many manifestations in the joints of psoriatic arthritis.
Philip J. Mease, MD: Mark, as you know, patients typically first have psoriasis sometimes up to 10 years before they will develop manifestations of musculoskeletal disease. In various studies, we have seen that somewhere around 30% of patients with psoriasis will ultimately develop some manifestation of psoriatic arthritis. In some settings, it seems to be less, in some, more, but that’s a reasonable figure, about a third.
Interestingly, when the patients are first presenting, it will often be with a swollen joint or what we call a dactylitic digit, where the whole digit is swollen and looks like a sausage, but when you probe the patient, it’s interesting to hear that really, that’s probably not the first manifestation. Sometimes, instead of arthritis as the first experience, they may have what we call enthesitis, where a tendon inserts in the bone, or a ligament inserts in the bone—anywhere in the body, really. It could be an Achilles tendon insertion, it could be the plantar fascia, could be around the kneecap, or it could be around the rib cage. The gristle of the rib cage in this case is the entheseal organ, where inflammation is occurring. They’ll go back and they’ll say, “I had problems with chest pain or Achilles tendinitis a year ago, 2 years ago, and it was quite stubborn and difficult to improve.”
On rare occasions, the person will have a history of back pain, which was part of the inflammatory arthritis of psoriatic arthritis. The key domains that we focus on from a musculoskeletal point of view are arthritis, tender and swollen joints; dactylitis, a sausage digit; enthesitis, wherever a tender ligament inserts in the bone and can be painful because of inflammation; and axial disease, or spinal disease. When I see a patient with psoriatic arthritis for the first time, I will tell them there is no one who is going to be just like you because no one is going to have the same mix of skin disease being mild or severe, joint disease being mild or severe, and entheseal inflammation being mild or severe. And it’s going to vary from time to time. It is like when you’re sitting in the symphony orchestra performance, and you hear, at times, the whole orchestra is profundo. We have everybody playing at once, and the audience is getting stirred out of their seats. Other times, when you can barely hear the piccolo section playing, or the cellos have a little solo going on. That will be how a person with psoriatic arthritis can perform.
Mark Lebwohl, MD: I love the analogy, and it makes me think of the piece that we’re missing, which is the nail involvement, which occurs in diseases and very commonly is a marker of psoriatic arthritis. That also has many manifestations. You can get nail bed disease, so that’s usually subungual hyperkeratosis. You can get nail matrix disease. That’s usually pinning in the nail, but you can also get salmon spots and crumbling of the nail, splinter hemorrhages, and a variety of other changes that occur, which are manifestations of nail psoriasis.
The other thing that I would say is, as you described in arthritis, there are patients who have minor plaques on the elbows or minor plaques in the scalp and some patients who carried them for years as seborrheic dermatitis, because all they have is some scalp scale. When they suddenly develop plaques on the elbows and knees, you realize that all those years, what you were calling seborrheic dermatitis is, in fact, psoriasis. By the way, I don’t consider it an error to have called it seborrheic dermatitis for all those years; it’s a very mild form of psoriasis.
Transcript Edited for Clarity