Tools help with diagnosis and assessment of psoriasis, psoriatic arthritis


Joseph Merola, MD, MMSc, (left) demonstrates how to conduct a psoriatic arthritis exam for early detection to prevent disability.

Treatments for psoriasis and psoriatic arthritis have improved greatly. However, it is important that the assessment of disease severity also improves because it helps patient management and quality of life. Live patient demonstrations were used to illustrate processes and tools for improved assessment during a July 28 session.

Attendees at “Practical Approaches to Assessing Psoriasis and Psoriatic Arthritis Patients in Clinic” (W002) received a mobile app and laminated cards to help evaluate and measure the severity of both diseases. For psoriasis, the app and laminated cards can guide clinicians to use validated tools such as body surface area (BSA), target lesion, and physician’s global assessment (PGA) scores to measure the severity of the disease in a clinical setting. Validated tools for diagnosing and assessing the severity of psoriatic arthritis also are available.


Alice Gottlieb, MD, PhD

“There are multiple reasons to improve assessment,” said Alice Gottlieb, MD, PhD, course director. “It helps improve communication with patients. It is helpful for prior authorizations and demonstrating excellent clinical outcomes.

“Early detection of psoriatic arthritis prevents disabilities. It gives dermatologists an opportunity to be able to at least take an educated guess to help get the patient to a rheumatologist sooner. We also have treatments that inhibit the progression of the disease.”


Mark Lebwohl, MD

Mark Lebwohl, MD, professor and chair of dermatology at Icahn School of Medicine at Mount Sinai, New York, demonstrated how to use the tools for psoriasis assessment by comparing patient lesions highlighted on a video screen to examples in the laminated cards to grade the severity of the disease.

“Many of these are tools that have existed for a long time,” he said. “They can be used to calculate the area affected and multiplied to get a PASI score. People talk about these scores all the time, and these tools can help understand fully what they mean.”

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Dr. Lebwohl (center) demonstrates how to assess severity of psoriasis.

Besides demonstrating how to develop PASI and PGA scores, Dr. Lebwohl showed how to use the palm method to estimate the Body Surface Area (BSA) involvement. He also discussed the Nail Psoriasis Severity Index (NAPSI), the Dermatology Life Quality Index (DLQI), and the Target Lesion Psoriasis Severity Score (TLPSS).

Joseph Merola, MD, MMSc, assistant professor of dermatology at Harvard Medical School, addressed patient assessment for psoriatic arthritis by discussing distinguishing characteristics of psoriatic arthritis versus other joint diseases, and referring patients to rheumatologists. Dr. Merola is board-certified as a rheumatologist as well as a dermatologist.

“One of the most important things is understanding the difference between inflammatory and non-inflammatory arthritis,” said Dr. Merola. “There are sites that are helpful for diagnosing some aspects of psoriatic arthritis. For example, enthesitis is the inflammation at tendon insertion points in the bone, which is something we see in psoriatic arthritis.”

A useful mnemonic in remembering assessment characteristics is the PSA Awareness Tool he helped develop:

  • P is for pain in the joints
  • S is for stiffness in the morning that lasts for more than 30 minutes, as well as sausage digit/dactylitis
  • A is for axial spine involvement, which is associated with inflammatory back pain and stiffness

Dr. Merola also reviewed the use of screening tools by dermatologists for distinguishing between inflammatory and non-inflammatory joint pain, and he encouraged dermatologists to work with rheumatologists familiar with psoriatic arthritis for patient referrals.

“Ultimately, diagnosing psoriatic arthritis can be a challenge, and that is where being partnered with a rheumatologist who is familiar with psoriatic arthritis can be really useful,” he said.

Bruce Elliot Strober, MD, PhD, discussed assessment scales for quality of life for psoriasis and psoriatic arthritis patents, including DLQI and various patient-reported outcomes scales (PRO). Dr. Strober, professor of dermatology at the University of Connecticut Health Center, stressed the importance of the development of PROs that would capture symptoms associated with psoriasis and psoriatic arthritis.

Targeted treatments for psoriasis and psoriatic arthritis were presented by Abby S. Van Voorhees, MD. Dr. Voorhees, professor of dermatology at Eastern Virginia Medical School, also reviewed strategies for optimal disease management that should target remission or low-disease activity.

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