The Importance of Early Intervention for Psoriatic Arthritis

Psoriatic arthritis continues to be one of the most common and chronic manifestations of psoriatic disease. Practical Dermatology® spoke with G. Michael Lewitt, who sits on the Medical Board of the National Psoriasis Foundation, to discuss diagnosis and treatment strategies for psoriatic arthritis.

What are the most effective treatments currently for psoriatic arthritis? 

Dr. G. Michael Lewitt: Fortunately for the dermatology community, 85% to 90% of psoriatic arthritis patients present with their skin involvement first. So, we are truly the first line, or the “infantry” in identifying that our psoriasis patients may have joint involvement. The most effective treatments are combination therapies. There is no one ideal solution for every patient. Up to 30% of patients with psoriasis have or will develop psoriatic arthritis, so if I recognize certain physical examination findings including, but not limited to, nail involvement, scalp involvement, large body surface areas, and/or genital psoriasis, I usually choose an agent that covers both skin and joints. Some agents are approved by the U.S. Food and Drug Administration (FDA) for one and not the other, but some are approved for both psoriasis and psoriatic arthritis. There is some disagreement about whether the ability to reduce radiographic progression matters clinically, and not all molecules have those bragging rights (nor has the endpoint even been studied). 

Starting out with modern oral therapies, apremilast has both psoriasis and psoriatic arthritis indications. Apremilast has additional data for scalp use, and I also use it a lot when a psoriatic arthritis patient presents with dactylitis, as I am convinced this small molecule works nicely in this area as monotherapy and as an augmentation to an injectable biologic. Beyond that, rheumatology guidelines are different than the dermatology guidelines in terms of the order of use of a specific mechanism of action. In dermatology, TNF inhibitors such as adalimumab, certolizumab, infliximab, and etanercept are not often first line because the patients in our offices can have a profound skin burden as well as joints. For broad psoriasis and psoriatic arthritis, I prefer the IL-17 drugs; of the four that are available, two—ixekizumab and secukinumab—are already FDA approved for psoriatic arthritis, and bimekizumab, hopefully, will be soon. Those are great drugs when I have any level of skin involvement alone plus or minus joint involvement. Both ixekizumab and secukinumab do possess inhibition of radiographic data at the 24-week marker. Meanwhile, two of the IL-23 inhibitors (risankizumab and guselkumab) are indicated for psoriatic arthritis, and they have great utility for enthesitis, dactylitis, and asymmetric oligoarthritis. Because they do not work as well as TNF inhibitors for ankylosing spondylitis (AS), which may or may not be related to AS-like manifestations of psoriatic arthritis, IL-23 inhibitors have been discounted for axial disease. But the AS type of psoriatic arthritis may just be different; studies are ongoing with different disease intervals in this mechanism of action. The other attribute about IL-23 inhibitors is that they can take longer to work in the joints. I am not changing patients’ regimens at 3 months; I may wait until 6 months before making a change or adding something to an IL-23. But usually, I am aggressive with the IL-17 inhibitors for patients who have suspected or likely psoriatic arthritis. 

Should combination therapy involve the rheumatologist?

Dr. Lewitt: Absolutely, but in the event there is a delay in the ability to consult rheumatology, I like to try some things on my own while the patient is awaiting another specialist appointment. There is very little utility for methotrexate in psoriatic arthritis, but there is a lot of utility for it in rheumatoid arthritis. Psoriatic arthritis is a very heterogeneous disease state; patients with psoriatic arthritis also have enthesitis, tendonitis, dactylitis, fasciitis, and all these other manifestations for which methotrexate does little to nothing. However, if a patient is doing extremely well from a skin standpoint on a given mechanism of action but still has some residual arthritis on an IL-17 or 23 inhibitor, I will often add apremilast—even though, technically, it is a synthetic, not a DMARD (disease modifying anti-rheumatic drug). As I mentioned earlier, residual dactylitis on a biologic is a great example of where I add apremilast. Other non-medication interventions that play a great role in psoriatic arthritis include physical therapy, ultrasound therapy, and intraarticular injections. Some eastern medicine can be considered. It is also important to employ recommendations for sleep hygiene, stress reduction, and diet. All of those would be options for combination therapy. We may even talk to a primary care endocrinologist about adding therapies such as semaglutide to reduce the burden of arthritis. It is multifaceted in that approach. But getting back to the original question: Yes, rheumatology plays a major role in management, and I am always open to having this specialty tweak and refine my plan with the patient.

What sorts of traditional treatments have become or are becoming obsolete? 

Dr. Lewitt: Methotrexate, in my opinion. Many insurance companies require it before other treatments, but I do not think it has utility in psoriatic arthritis or, frankly, in psoriasis. If you look at Number Needed to Treat analysis just for skin disease, you need to treat more than 26 patients with methotrexate to get one clear; with some of our new IL-17 and IL-23 inhibitors, you can treat two people to get one completely clear. I don’t know if that has taken course as much in the rheumatology community, but the rheumatologists I work with closely are not using methotrexate unless it is for a brief period as required by an insurance company with the goal of obtaining a more modern and appropriate therapy.

What kinds of conversations need to be had with patients upon the initial psoriasis diagnosis about the potential of psoriatic arthritis, or eventually upon the psoriatic arthritis diagnosis? 

Dr. Lewitt: That is an important question. If I have a good rapport with a patient, I sometimes joke that, “I don’t care about your skin.” I then clarify that, of course, I care about their skin, but we are fortunate to have a large number of systemic modalities and some great topical modalities—steroidal and non-steroidal—that can clear skin disease. If we need to improvise/adjust in the middle of treatment, we can. Even with a flare, I can almost always reverse your skin condition with the current tools we have. Conversely, psoriatic arthritis is irreversible and destructive. There is often no going back once you have had long-standing and/or progressive and rapid inflammation in the joints and musculoskeletal attachments; you start to see both clinical and radiographic changes for this disease state. When a patient is hesitant or apprehensive, it is absolutely imperative to be honest with them about the importance of being aggressive in terms of therapies and timeline to avoid the often irreversible and destructive nature that is psoriatic arthritis.