Beyond the Skin: Catching the Subtle Clues of Psoriatic Arthritis

At the Rapids 2026 conference in Fort Lauderdale, Florida, Eileen Cheever, PA-C,  sat down with rheumatologist Dr. Shikha Singla to discuss a critical healthcare gap: bridging the divide between dermatology and rheumatology to catch Psoriatic Arthritis (PsA) early.

For dermatology providers, recognizing the "pre-PsA phase" can entirely change a patient's long-term quality of life. Here are the clinical pearls, referral tips, and collaborative strategies Dr. Singla shared during the session.

Spotting the Pre-PsA Phase: History is Key

Before structural joint damage shows up on an X-ray, patients experience a subtle "pre-PsA phase." Dr. Singla emphasizes that identifying this phase requires listening to the nuanced history of a patient’s pain rather than relying solely on labs.

When a psoriasis patient complains of joint pain, ask these three questions to differentiate inflammatory arthritis from mechanical issues (like osteoarthritis):

• How fast did it start? Acute onset often points to an acute inflammatory condition, whereas a slow, years-long burn can look different—though chronic inflammatory conditions also build over time.
• When is it worst? Inflammatory pain is notoriously worse in the morning or after periods of rest.
• Does movement help? If the pain improves with physical activity, it’s likely inflammatory. If it gets significantly worse with movement, it leans mechanical.

Underutilized Physical Exams

You don't need a rheumatology fellowship to perform a quick joint check. Dr. Singla noted a few quick maneuvers dermatology providers can easily integrate into daily skin exams:

1. Check the hands: Look for joint effusions and synovitis in the MCP, PIP, and DIP joints.
2. Inspect the heels: Check the Achilles tendon insertion and look for retrocalcaneal bursa enlargement (enthesitis).
3. Watch for "Sausage Digits": Dactylitis (swelling of an entire finger or toe) is a major red flag.

Clinical Tip: Patients are often pleasantly surprised when a skin specialist checks their joints. Putting your hands on their joints builds immense trust and boosts patient confidence in their collaborative care.

Sorting Through the Diagnostics: Labs & Imaging

A common misconception is that extensive lab work or imaging is required before sending a patient to a rheumatologist. Dr. Singla cleared up the confusion:

The Role of Ultrasound and MRI

Ultrasound and MRI are not diagnostic tools for PsA—the diagnosis remains strictly clinical. However, they are incredibly useful for confirming inflammation or checking for fluid inside the joints when the clinical picture is blurry. Keep in mind that ultrasound is highly user-dependent.

What Labs Should You Order?

In short: None. Dr. Singla explicitly noted that dermatology APPs do not need to run a battery of tests before a referral.

"I don't think I need any labs from dermatology, especially ANAs... I don't expect my dermatologist to run any labs or imaging before sending the patients to me."

Understanding the CASPAR Criteria

While the CASPAR (Classification Criteria for Psoriatic Arthritis) is primarily used for research and clinical trials rather than daily clinic diagnoses, it's a helpful framework to keep in mind. Points are awarded for:

• Active skin psoriasis, a personal history, or a family history of it.
• Nail disease (pitting, onycholysis).
• Dactylitis.
• A negative rheumatoid factor (RF) is a key differentiator from rheumatoid arthritis.
• Radiographic evidence of new bone formation.

Overcoming Barriers to the "Combined Clinic"

We all love the idea of a joint Derm-Rheum clinic, but logistical realities often get in the way. Dr. Singla highlighted a few major barriers and how their clinic overcame them:

When Skin is Clear, but Joints are Screaming

What happens when a patient is on a biologic that gives them 100% clear skin, but their joint pain is actively worsening?

Before you switch therapies, Dr. Singla advises a step back. You must evaluate whether the lingering pain is truly active PsA inflammation or something else, such as osteoarthritis, gout, or fibromyalgia. Additionally, check for axial (spine) involvement or comorbidities such as Inflammatory Bowel Disease (IBD), which can help determine which biologic pathway to choose next.

Case Study: The "Refractory" Patient

Dr. Singla shared a case of a 51-year-old woman with a 7-year history of PsA who had cycled through multiple rheumatologists and biologics. She had lingering joint pain and a history of dactylitis, but her inflammatory markers (CRP, ESR) and joint ultrasounds were entirely normal.

The twist? Her original psoriatic arthritis had actually been successfully treated by the biologics. Her ongoing, lingering pain was due to secondary fibromyalgia. By stopping the drug-cycling wheel and referring her to physical therapy and cognitive behavioral therapy (CBT), her symptoms finally improved.

The Verdict on the Perfect Referral

When sending a patient over to rheumatology, the ideal referral contains a specific clinical question.

Instead of a generic "Please evaluate for PsA," try framing it around the nuances of their current therapy: "Patient's skin is well-controlled on an IL-23 inhibitor, but they are experiencing persistent Achilles tendon pain. Is this mechanical wear-and-tear, or active enthesitis?" By working together, catching the early historical clues, and bypassing unnecessary lab delays, dermatology and rheumatology providers can stop psoriatic arthritis in its tracks—long before the joints pay the price.

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