Psoriatic arthritis eludes early diagnosis


Most patients with psoriatic arthritis first present with psoriasis only. Their skin disorder precedes any joint involvement, often by several years. That suggests targeting interventions to patients with psoriasis to prevent or slow their progression to psoriatic arthritis, as well as following psoriatic patients closely to diagnose psoriatic arthritis quickly when it first appears. It’s a simple and attractive management premise that’s been challenging to apply in practice.

It’s not that clinicians aren’t motivated to diagnose psoriatic arthritis (PsA) in patients early, hopefully as soon as it appears. The susceptibility of patients with psoriasis to develop PsA is well described, with an annual progression rate of about 3%, and adverse consequences result from even a 6-month delay in diagnosis.

Dr. Lihi Eder, Women's College Hospital, Toronoto

Dr. Lihi Eder

“Some physicians still don’t ask psoriasis patients about joint pain, or their symptoms are misinterpreted as something else,” said Lihi Eder, MD, a rheumatologist at Women’s College Research Institute, Toronto, and the University of Toronto. “Although there is increased awareness about PsA, there are still delays in diagnosis,” she said in an interview.

“Often there is a massive delay in diagnosis, and we know from a number of studies that longer duration of symptoms before diagnosis is associated with poorer outcomes,” said Laura C. Coates, MBChB, PhD, a rheumatologist at the University of Oxford (England). The delay to PsA diagnosis is generally “longer than for equivalent rheumatoid arthritis patients. PsA patients take longer to ask a primary care physician for help, longer to get a referral to a rheumatologist, and longer to get a diagnosis” from a rheumatologist. “We need to educate patients with psoriasis about their risk so that they seek help, educate GPs about whom to refer, and educate rheumatologists about diagnosis,” Dr. Coates said.

“It is very important to diagnose PsA as early as possible. We know that a delay in diagnosis and treatment can lead to worse outcomes and joint damage,” said Soumya M. Reddy, MD, codirector of the Psoriasis and Psoriatic Arthritis Center at New York University Langone Health in New York. “The heterogeneity of clinical manifestations of PsA can make it difficult to diagnose, and in some cases this leads to delayed diagnosis.”

Dr. Joseph F. Merola, Brigham and Women's Hospital, Boston

Dr. Joseph F. Merola

“We are increasingly interested in the concept of preventing PsA. Psoriasis is a unique disease state in which we have an at-risk population where 30% will develop an inflammatory and potentially damaging arthritis. This may become important as our skin treatments may also treat musculoskeletal components of the disease,” said Joseph F. Merola, MD, director of the Center for Skin and Related Musculoskeletal Diseases at Brigham and Women’s Hospital in Boston and double board certified in dermatology and rheumatology.


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