Many psoriasis patients develop psoriatic arthritis. Dermatologists should be on the lookout for arthritis symptoms and refer patients to rheumatologists when appropriate.
The dual nature of psoriatic arthritis lurks in its very name: It’s a skin condition and a joint condition, one that could warrant treatment by both a dermatologist and a rheumatologist.
But dermatologists may not realize the heightened risk of arthritis in psoriasis patients, know how to detect signs of joint pain or understand the role that rheumatologists can play.
“This is a prime example of when it’s good to think about things beyond skin when we’re taking care of patients,” says April W. Armstrong, M.D., M.P.H. “In psoriasis patients, we need to think about their joints because if you catch psoriatic arthritis early and treat it early, biologics can actually halt the progression of joint destruction.”
Dr. Armstrong and Joel M. Gelfand, M.D., MSCE, are using medical education to boost links between dermatologists and rheumatologists. Earlier this year, they held a continuing medical education session about this topic in conjunction with CME Outfitters. Both physicians spoke with Dermatology Times about lessons for their fellow dermatologist about psoriatic arthritis.
The number of sufferers is large. Dr. Gelfand led a 2005 study that estimated 2.5 percent of whites and 1.3 percent of blacks in the U.S. suffer from psoriasis. According to the National Psoriasis Foundation, studies estimate that 10-30 percent of psoriasis patients will develop psoriatic arthritis.
“They get morning stiffness in their joints initially, and then they can get pain and swelling in the joints,” says Dr. Armstrong, who’s vice chair of Clinical Research, associate professor of Dermatology, director of Clinical Trials and Outcomes Research and director of the Psoriasis Program at the University of Colorado School of Medicine. “It can affect the small joints of the hand and feet and larger joints such as the knee and spine.”
If left untreated, she says, psoriatic arthritis can lead to joint deformation and functional impairments that may prevent sufferers from holding a cup or picking up a pencil.
It’s not clear how psoriasis and arthritis are linked, and scientists aren’t clear if one even prompts the other.
“We characterize the connection as associated,” Dr. Armstrong says. “There are commonly shared inflammatory pathways between the two conditions, and shared genetic loci too.”
Dermatologists should not assume that they can easily detect psoriatic arthritis, says Dr. Gelfand. He is associate professor of Dermatology and Epidemiology and medical director of the Dermatology Clinical Studies Unit at University of Pennsylvania Perelman School of Medicine.
“The biggest misconception is that psoriatic arthritis is easy to diagnose,” he says. “Indeed, studies demonstrate that about 10% of psoriasis patients seen by dermatologists have psoriatic arthritis that is not identified by the dermatologist. Psoriatic arthritis can also be confused with fibromyalgia and osteoarthritis, both of which are quite common in patients with psoriasis.”
Dr. Armstrong recommends actively screening psoriasis patients for psoriatic arthritis. This is especially important, she says, because an estimated 85 percent of psoriatic arthritis patients will develop skin problems before joint problems or concurrently. The majority will get skin problems first, she says.
READ: Psoriasis Guidelines
To make things more complicated, “patients usually don’t remember to bring up joint problems,” she says. “They think that they are there for the treatment of skin disease, and they often do not make the association.”
When examining a patient with psoriasis, Dr. Armstrong recommends asking questions such as:
In addition, she says, “at the very least, we should encourage dermatologists to take it a step further to look at the joints, palpate the joints.”
If dermatologists want to do more, Dr. Gelfand says they can order X-rays of affected small joints in the hands and feet. And they can turn to blood tests to provide more information since psoriatic arthritis is “a diagnosis of exclusion,” he says. “I often order blood tests such as RF and CCP to rule out rheumatoid arthritis and CRP to look for signs of inflammation that may suggest a more aggressive clinical course.”
If there’s no sign of psoriatic arthritis, Dr. Gelfand recommends that dermatologists still talk to patients about the issue.
“It is important to educate them so they know what signs and symptoms to look out for so that the diagnosis can be established early in the course of disease and proper treatment can be instituted,” he says.
But if a dermatologist is even slightly suspicious that psoriatic arthritis is present, Dr. Gelfand recommends a referral to a rheumatologist. The threshold for action should be low, he says.
Rheumatologist David G. Borenstein, M.D., MACP, FACR, MACR, also took part in the continuing education session. He is a clinical professor of medicine with the Division of Rheumatology at The George Washington University School of Medicine and Health Sciences in Washington D.C.
He agrees with Drs. Armstrong and Gelfand about the importance of simply asking psoriasis patients if their joints hurt.
“If the answer is yes, then the next question is: Should I just send them to rheumatologist, or am I interested enough to ask additional questions?”
Either way, he says, communication between the rheumatologist and dermatologist is important once a referral is made.
“I make sure that the dermatologist gets a note from me as to what I’m thinking. Do I call them all the time? No. But I certainly write to them saying this is going on and we need to use this or that treatment.”
One challenge facing dermatologists and rheumatologists is that psoriasis in the skin may progress faster than arthritis or vice versa.
“There’s no one-to-one correlation,” Dr. Borenstein says. “For instance, the dermatologist may see a very small amount disease, 1% or less of skin involvement, which would suggest they just need to use a topical treatment. But the rheumatologist may be seeing changes in joints that are quite worrisome. That may necessitate a difference in the level of treatment.”
Whatever the case, he says, psoriatic arthritis can not be not cured, and damage is not reversed. “I can’t fix what’s broken, but I can try to prevent it from being broken more,” he says. “We have lots of therapies now which can be very helpful in stopping progression.”
Rheumatologists treat many of these patients with biologics, he says. While dermatologists use many of the same drugs as rheumatologists, he says, dermatologists can turn to their rheumatology colleagues for guidance if needed, he says. “We can be a resource for a dermatologist who’s concerned about whether to put a patient on a biologic or not.”
Communication between dermatologists and rheumatologists is crucial for another reason, Dr. Armstrong says: It can prevent overlapping medications.
In the big picture, Dr. Borenstein says, “cooperation between rheumatologists and dermatologists can be quite helpful for the patient. Everyone knows what they’re responsible for, and we hope the best care for the patient will result.”
Disclosures: Dr. Gelfand served as a consultant for Abbvie, Amgen, Celgene, Coherus, Eli Lilly, Janssen Biologics (formerly Centocor), Leo, Merck, Novartis Corp and Pfizer, and received honoraria. He receives research grants (to the Trustees of the University of Pennsylvania) from Abbvie, Eli Lilly, Janssen, Novartis Corp, and Pfizer Inc. Dr. Borenstein consults for Amgen, Janssen, Epirus, Zogenix and Pfizer. Dr. Armstrong has received research and grant support from Amgen, Eli Lilly, Janssen Pharmaceuticals, Merck, and Pfizer. She serves as a consultant for AbbVie, Amgen, Eli Lill and Janssen Pharmaceuticals.