SAN ANTONIO — In the course of caring for individuals with psoriasis, clinicians should have patients complete the validated Psoriasis Epidemiology Screening Tool (PEST) for psoriatic arthritis (PsA) every 6 months, as recommended by the National Psoriasis Foundation, advised Shikha Singla, MD. 

“That’s because a delay of more than 6 months leads to worse outcomes and disabilities in our patients,” said Singla, associate professor of medicine (rheumatology) at the Medical College of Wisconsin, during a presentation at the Society of Dermatology Physician Associates (SDPA) Fall Dermatology Conference. “This is the most commonly used screening tool” for PsA, she noted

PEST consists of the following five questions that patients can answer in the office before seeing the clinician: 

• Have you ever had a swollen joint (or joints)?
• Has a doctor ever told you that you had arthritis?
• Do your fingernails or toes have holes or pits?
• Have you experienced pain in your heel?
• Have you had a finger or toe that was completely swollen and painful for no apparent reason?

Each “yes” response equals one point, and a total score of three or higher indicates a potential risk for PsA, warranting consideration for referral to a rheumatologist, Singla said. The PEST is also available in the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) mobile app. 

Other validated tools to consider include the 15-question Psoriatic Arthritis Screening and Evaluation questionnaire and the 13-question Toronto Psoriatic Arthritis Screening (ToPAS) questionnaire, according to Singla.

Drawing from a 2025 review on PsA screening and management published in the Journal of the American Academy of Dermatology, Singla discussed the mnemonic PSA, in which P stands for joint pain; S stands for stiffness after a period of inactivity lasting more than 30 minutes and/or swelling or a sausage digit; and A stands for axial or spinal involvement (back pain associated with stiffness after inactivity that improves with movement). The presence of any two of the three features (P, S, or A) suggests that the patient may have PsA. “Most patients with degenerative disk disease will say that their pain worsens with movement,” and this is “completely the opposite,” Singla noted. 

In a 2019 published review on PsA for dermatologists, authors Alice Gottlieb, MD, and Joseph F. Merola, MD, propose the following questions to ask patients during office visits: 

• Do you have a family history of psoriasis or psoriatic arthritis?
• Have you ever had tender/swollen fingers or toes?
• Do you experience morning stiffness lasting longer than a half-hour to 1 hour?
• Does your pain improve with exercise?
• Have your symptoms of joint pain persisted for more than 3 months?
• Does your pain improve with nonsteroidal anti-inflammatory drugs?
• How would you describe your pain (gnawing, throbbing, deep)?

A “yes” response to any of the questions supports the possible presence of inflammatory arthritis.

“When I see patients with degenerative arthritis, they say none of the medications help,” Singla said. “But psoriatic arthritis patients do say that meloxicam or any other NSAID helps.” 

In the realm of differential diagnoses, rheumatoid arthritis (RA) is a common consideration. “But you usually don’t see dactylitis in RA patients; you don't see a lot of enthesitis,” she said. Other differential diagnoses include fibromyalgia, gout, and osteoarthritis, but the swelling in osteoarthritis “is more bony,” she said.

“Sometimes we see two or three diseases together,” Singla noted. “Treatment for these diseases is based on a treat-to-target approach. There are different disease outcomes.” 

Singla concluded her presentation by referencing a 2020 published article by Spanish investigators that proposed a clinical control algorithm for PsA to be used in dermatology consultations.

Singla reported no relevant financial relationships. 

Doug Brunk is a San Diego-based medical journalist.