Optimizing Patient Care: Collaboration Between Dermatology and Rheumatology

A recent abstract published in the Journal of Cutaneous Medicine and Surgery reviewed and created a risk stratification strategy for early referral of patients with psoriatic arthritis to minimize erosive joint damage by combining the Psoriasis Epidemiology Screening Test (PEST) with the classification criteria for psoriatic arthritis (CASPAR). Joining The Dermatologist was Dr Yassein Shamout, one of the abstract’s lead authors, to discuss how dermatologists and primary care physicians can collaborate with rheumatologists using psoriasis screening tools.

Yassein Shamout, MD, FRCPC, DABD, is a board-certified dermatologist in the division of dermatology at McGill University in Montreal, QC, Canada.

How can PEST combined with CASPAR improve the rheumatology referral process?

First, I think it's important to know what PEST is and what CASPAR is. PEST is a 5-part questionnaire where you can ask the patient their history, such as if they've ever had joint pain, if they've been diagnosed with arthritis, or if they’ve ever had undiagnosed painful joints in the past. If they answer at least 2 with yes, then they actually qualify for further work-up and investigation. This then goes to the physical exam section and investigation, which uses the CASPAR criteria. The CASPAR criteria are basically looking at the patient and determining if they have a personal history of psoriasis, if they've had a history of psoriasis previously, if someone in the family has a history of psoriasis, or if they have pitting of the nails or nail changes that are secondary to psoriasis. Additionally, on the exam section, you're looking for dactylitis, where there are 2 investigations that you'll have to conduct— a rheumatoid factor level in the blood and x-rays.

Going back to the question on how this can improve the referral process, classically in dermatology residency programs and training, we're only taught about the CASPAR criteria because we predominantly focus our interview on the physical exam and investigation section. Usually, we just screen the patient by asking them, "Do you have joint pain?", and that's really it. If they say yes or no, that determines if we consult rheumatology or not, but it doesn't give us a sense of urgency.

So, by using the questionnaire, at least we can get a sense of urgency and filter out patients that have a low likelihood of having psoriatic arthritis. This is so we know how much time we have, because since psoriatic arthritis leads to irreversible joint damage, it's important to detect these patients early. By determining a cutoff for PEST scoring in addition to the CASPAR scoring and combining them for the first time, we're able to at least provide the rheumatologist a sense of urgency for the consultation. I think that would translate into better patient care, and that's the hope for future studies.

How can dermatologists and primary care physicians collaborate with rheumatologists using this risk stratification algorithm?

What we did initially a year ago, we sat with a group of rheumatologists and dermatologists, and they encouraged us to provide the scoring criteria to at least help them determine a sense of urgency. I think it's important to have a good network of different specialists, especially in the area that you practice or even within educational institutions. There must be an agreement on if the rheumatologist will accept a consult like this, or if they will actually look for these criteria to actually help streamline the patients.

If the suspicion is extremely high for psoriatic arthritis, which we know can cause irreversible joint damage, we can take the steps to add investigations that can rule out other causes of arthritis and would help with diagnosis, such as x-rays, rheumatoid factor levels, and adding CRP to the blood work, for example. We can also initiate baseline blood tests in anticipation of immunosuppressive therapy. This way when the patient sees the rheumatologist, everything is there, and they can start their treatment and diagnosis in the same visit.

How can PEST combined with CASPAR assist in early detection for patients with psoriasis and psoriatic arthritis?

I think that patients that have at least a score of 2 or more on the PEST criteria qualify for further investigation, at least looking at the rheumatoid factor levels as well as x-rays to help add more to the CASPAR criteria scoring. However, it's not uncommon for patients to come in with a psoriasis on their skin in addition to nail changes. This already puts them at a CASPAR of 3. If they have a PEST score of 2 or more, we can actually start initiating workup by adding the x-rays, blood work for rheumatoid factors, and CRP levels. Again, we would also be doing the baseline blood work for the patient in anticipation of the immunosuppressive therapy. Once we have the criteria, the patients should be seen within 3 months by a rheumatologist. By that point they would have all the information to make a diagnosis and a treatment point for the patient.

Is there anything else you’d like to share with your colleagues regarding PEST or early detection of psoriatic arthritis?

I found in our training program among different dermatology meetings that we tend to stay in our silos. Dermatologists hang out with dermatologists and rheumatologists hang out with rheumatologists. However, I really feel like innovation and changing guidelines to improve patient care comes from having both specialties sit together to hold a discussion and see how each specialty thinks to bridge the gap.

This is exactly what happened a year ago in my first week of practice. I went to a meeting for rheumatologists and dermatologists, and I just listened. Just by listening, I was able to see what we're missing as dermatologists, what we're not using, and what rheumatologists look for that's important. I feel like that's the first step in having a good collaboration among different specialties to improve patient care.