Could Isolated Nail Psoriasis Predict Psoriatic Arthritis?

In a cross-sectional study of 36 isolated nail psoriasis patients, 7 of them (19%) went on to develop psoriatic arthritis in the following years. Is there more to this connection between isolated nail psoriasis and early detection of PsA? Dr Shari Lipner of Weill Cornell Medical Center explains.

Shari Lipner, MD, PhD, is an associate professor of clinical dermatology and director of the nail division at the New York-Presbyterian Hospital/Weill Cornell Medical Center.

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Transcript:

Any views and opinions expressed are those of the authors and/or participants, and do not necessarily reflect the views, policy or position of the Rheumatology and Arthritis Learning Network or HMP Global, its employees and affiliates.

RALN:

Welcome to this podcast from the Rheumatology and Arthritis Learning Network. I'm your host, Priyam Vora, and today we are talking with Dr. Shari Lipner. Dr. Lipner is an associate professor of clinical dermatology and director of the nail division at the New York Presbyterian Hospital, Weill Cornell Medical Center. Today we are going to discuss her research into how a delayed diagnosis of nail psoriasis may significantly increase the risk of psoriatic arthritis. Thank you for joining us today. Before we get into the details of the research and the findings for our listeners, can you please explain what is isolated nail psoriasis?

Dr. Shari Lipner:

Yes, that's a great question. A lot of people don't know that term. So we know that a large proportion of psoriasis patients experience nail changes during their lifetimes. But there's a small subset of psoriasis patients and this is about five to 10% that have nail changes with no or limited cutaneous findings, less than 5%. And these are the patients that are hardest to diagnose because we don't have the clues from the skin.

RALN:

All right. I understand that nail alteration or nail morphology is fairly common among patients with psoriasis. However, not much is known about the association between isolated nail psoriasis and psoriatic arthritis. Is this what prompted your research?

Dr. Shari Lipner:

Yes, we were observing that patients with nail psoriasis were often misdiagnosed with other nail disorders such as onychomycosis or nail fungus. And they had other treatments including antifungals before seeing us in the nail clinic. Some of them even had joint pain and we know that in a cross-sectional study of 36 patients with isolated nail psoriasis, so a small study, about 20% developed psoriatic arthritis. And in a retrospective study of over 4,000 psoriasis patients, nail changes were the strongest predictor of having psoriatic arthritis, almost threefold risk. So we were interested in characterizing the clinical and histological characteristics and prevalence of psoriatic arthritis in patients with isolated nail psoriasis.

RALN:

Right, thank you. Would you describe the general outline of your study?

Dr. Shari Lipner:

Yeah, so this was a retrospective study where we analyzed all patients with isolated nail psoriasis at our institution over a 20-year period. And we looked at demographics, clinical characteristics, and histopathologic data. We calculated NAPSI scores from clinical photographs. And for statistical analysis we used chi-squared and two-tailed T-tests.

RALN:

And what did you find?

Dr. Shari Lipner:

So in total there were 87 patients with isolated nail psoriasis, roughly half females with a mean age of 46 years. Average time to presentation was almost three years and patients had an average of eight nails involved. 10 patients or 11% had psoriatic arthritis and there was some concordance between the nails and the joints that were affected. And for eight out of 10 patients, arthritis was present at the same time or proceeded the nail changes.

RALN:

So during your research, did you identify any trends in the prevalence of nail psoriasis across various demographic differences such as age, gender, race, socioeconomic factors, or maybe smoking habits?

Dr. Shari Lipner:

Yeah, so we looked at all of the demographic factors and what we found was that patients with psoriatic arthritis had higher NAPSI scores than those without arthritis, and on average they were older.

RALN:

All right, okay. And what are the markers that identify isolated nail psoriasis? Are there any blood tests or imaging studies?

Dr. Shari Lipner:

So that's what makes it so hard to diagnose nail psoriasis, especially when there are no or limited skin findings. There's no blood tests or imaging studies right now that will help us. But clinically in our study, the most common clinical features were onycholysis, which means separation of the nail plate from the nail bed and nail plate pitting, which were indentations in the nail plate. And together this was the most common combination. And the most common histological features were parakeratosis and neutrophil infiltration.

RALN:

Okay. So is diagnosing isolated nail psoriasis something a primary care physician can do? Or does it require the special expertise of a dermatologist or a rheumatologist?

Dr. Shari Lipner:

So diagnosing isolated nail psoriasis requires education and exposure. I think primary care doctors could diagnose nail psoriasis if they learn the key clinical features and see enough cases.

RALN:

So let's say symptoms of nail psoriasis in a patient are detected and the rheumatologist suspects that something bigger is brewing like progression to PSA, what next? What are the next steps you would recommend to fellow rheumatologists?

Dr. Shari Lipner:

So the first step is to take a clipping and the rheumatologist might want to partner with a dermatologist to perform the clipping that will help rule out onychomycosis and other nail diseases. Then a careful joint examination and imaging studies are needed.

RALN:

Got it. So is there a reciprocal relationship between nail psoriasis and psoriatic arthritis? Meaning right now we are talking about how nail psoriasis could possibly lead to psoriatic arthritis, but can psoriatic arthritis cause nail psoriasis to present?

Dr. Shari Lipner:

In our study for 80% of the patients with psoriatic arthritis joint pain presented at the same time as the nail changes or before the nail changes and for 20% it was the opposite. So our study suggests that it can go both ways. Nail psoriasis may lead to psoriatic arthritis and psoriatic arthritis may cause the nail changes. And this is because the extensor tendon is so close to the nail unit.

Priam Bora:

Okay. Do you have any plans to expand this to a broader study?

Dr. Shari Lipner:

Since the nail psoriasis population is so small, particularly the isolated nail psoriasis, a broader study would require multicenter efforts and yes, we are definitely trying to do this.

RALN:

Okay. Before we end, is there something you would like to add? Maybe I forgot to ask you something you would want to share?

Dr. Shari Lipner:

I think one of the main takeaways of our study is that patients with isolated nail psoriasis are being missed. And so it's very important for rheumatologists to recognize the key clinical features and diagnose isolated nail psoriasis as soon as possible. Because diagnosing and treating early can make a huge difference for these patients.

RALN:

Right, right. Okay. Thank you so much for taking the time to talk to us. Once again for our listeners, that was Dr. Shari Lipner reminding us the role dermatologists can play in early diagnosis of isolated nail psoriasis. And how that can improve the patient's overall quality of life and possibly prevent progression to psoriatic arthritis. Thank you, Dr. Lipner.

Dr. Shari Lipner:

Thank you so much.

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