First international guidelines for treatment of psoriatic arthritis

October 26, 2008

Rheumatologists, dermatologists, and patient advocates have come together to publish the first-ever international guidelines for the treatment of psoriatic arthritis, a disease that mainly affects people who have psoriasis but also some people without it.

The guidelines by the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) were presented at the annual meeting of the American College of Rheumatology. The group was headed by Christopher Ritchlin, M.D., M.P.H., professor of Medicine at the University of Rochester Medical Center, who presented the guidelines Sunday, Oct. 26.

"In the past few years, new medications have become available that are incredibly effective for the various manifestations of psoriatic arthritis," said Ritchlin, who treats about 250 patients with the disease. "Many patients' find their lives changed for the better within just a couple of weeks. These guidelines are designed as a platform to make sure physicians around the world are aware of what's available for their patients and to help them make sound treatment decisions."

Psoriatic arthritis is an oft-forgotten cousin to its better known counterparts, osteoarthritis and rheumatoid arthritis. Doctors estimate that somewhere between 500,000 to 1 million people in the United States have psoriatic arthritis. Doctors say that about one out of four patients with psoriasis also gets psoriatic arthritis, and that conversely, about 15 percent of people who get the disease don't have psoriasis.

It's an autoimmune disease in which errant signaling molecules causes a person's body to attack itself. The disease literally eats away at patients' joints, causing some bones or digits such as fingers or toes to shrink or literally disappear while also triggering abnormal, disfiguring and disabling bone growth in their hands, feet, spine, and other joints. Doctors are also finding that patients with psoriasis are more prone that others to several ailments, including diabetes, high blood pressure, and heart attacks.

"The presenting symptoms of psoriatic arthritis vary tremendously from patient to patient," said Ritchlin. "It's a very challenging disease to treat, because so many different parts of the body can be involved. The skin can be inflamed, a particular joint or tendon can hurt tremendously, the patient might have back pain, or a single swollen finger or toe.

"Oftentimes a patient will come in with something you might call 'tennis elbow,' or they might have a sore Achilles heel, and that's their only symptom. It can be very difficult to diagnose," said Ritchlin, who is director of the Clinical Immunology Research Unit at the Medical Center. He has served as a consultant to Amgen, Wyeth, Abbott, and Centocor, and has received research funding from Centocor, Abbott, and Amgen.

A broad range of treatments is available to treat the disease. Options include non-steroidal anti-inflammatory drugs like ibuprofen and steroids injected into joints or tendons.

Other anti-inflammatory medications known as disease-modifying antirheumatic drugs, such as methotrexate, are often used, but GRAPPA found that the medications are often not effective for psoriatic arthritis, even though they can be very useful for treating rheumatoid arthritis, Ritchlin said.

The group recommended that patients see a specialist, such as a dermatologist or rheumatologist, as soon as psoriasis or psoriatic arthritis is suspected. Currently a large number of patients with psoriatic arthritis never see a rheumatologist, and many patients go undiagnosed, Ritchlin said.

The group also recommended that newer medications that inhibit a molecule known as TNF (tumor necrosis factor) be considered by physicians. The first anti-TNF compound, etanercept, was approved by FDA in 1998 to treat rheumatoid arthritis, and then was approved in 2002 to treat psoriatic arthritis. Similar drugs include infliximab and adalimumab.

"Most people respond rapidly and dramatically to these medications," said Ritchlin, who led a research team at Rochester that described the central role of TNF in the bone damage that occurs in psoriatic arthritis. Recent estimates indicate that less than 20 percent of psoriatic arthritis patients are on anti-TNF medications.

Source: University of Rochester