Expert insights: High-yield clues to catch PsA early and stay ahead of progression

You’re seeing a patient who suspects they have psoriatic arthritis (PsA). What’s in your diagnostic toolbox?

Because PsA is complex and heterogeneous, especially early on, you might find diagnosis especially challenging. It requires an amalgam of clinical experience, a trial-and-elimination process, and guidance from research and guidelines.

Review the latest guidelines

As Abhijeet Danve, MBBS, MD, MHS, a rheumatologist and associate professor of medicine at Yale Medicine, says you need to have a high suspicion of PsA to diagnose it accurately in the early stages.

This is where the Classification Criteria for Psoriatic Arthritis (CASPAR)—guidelines that can help support a PsA diagnosis—come into play. ^[]

As Erin Hammett, MD, triple board-certified physician in rheumatology, internal medicine, and lifestyle medicine, and medical director at WellTheory, explains: “You’ll ask about symptoms and a personal or family history of psoriasis, examine their joints and skin, and look for clues like swollen ‘sausage’ fingers or toe and nail changes,” she says. “[Patients] do not have to have psoriasis to develop psoriatic arthritis, as 30% of the time skin psoriasis is diagnosed after the onset of inflammatory arthritis.”

Differential diagnoses could include rheumatoid arthritis, reactive arthritis, other spondyloarthropathies, osteoarthritis, or crystal arthropathies. ^[]

But it’s important to note that the CASPAR criteria alone aren’t always enough to make a diagnosis. For example, a patient may present with subclinical PsA. That's why diagnosis really comes down to judgment and context. ^[]

Spotting early PsA

In early PsA, your patients’ skin may not be affected. You might see significant joint stiffness, dactylitis, enthesitis, and fatigue. At this stage, patients might present with asymmetric oligoarticular arthritis, indicating that four or fewer joints are impacted.

But as PsA progresses, patients may see severe joint swelling, mobility issues, joint damage, and even deformities, Dr. Danve explains. 

First, oligoarticular arthritis may be misunderstood as being “less severe” than polyarticular disease. However, this can progress to more erosive polyarticular disease in which more joints are affected. ^[] These patients tend to present with dactylitis and enthesitis, and may even have a higher prevalence of axial symptoms and comorbidities than those with polyarticular PsA. 

More so, recent research published in Clinical Rheumatology found that older male patients with higher Disease Activity Index for Psoriatic Arthritis (DAPSA) scores and initial polyarticular involvement may experience worse progression of bone destruction. ^[]

So, what can you do? Early diagnosis and phenotypic classification is key. Getting early radiographic assessment is the goal, while rigorous monitoring can be used to preempt and manage progression. ^[]