What’s Your PsA Domain?

Knowing your PsA type and domain can help you customize a more effective treatment plan (and what’s not to like about that?).

by Megan McMorris Health Writer

Psoriatic arthritis is a unique condition. Unlike other forms of arthritis, which target the joints, PsA is also associated with changes to tendons, ligaments, skin and nails. Plus, it has a chameleon characteristic, where it can take on a dramatically different appearance in one person versus another.

This, at times, makes PsA a more complicated condition to treat. However, doctors have found that splitting the disease into five different location-based types—and, more recently, into six different domains—can help more effectively target each patient’s needs. The domains, which are classified by how PsA manifests in the body and include more about the nuances of the disease than the types do, may be especially crucial for pinpointing treatment strategies.

“Treatment isn’t a one-size-fits-all approach, but the domain and severity of the condition—along with other factors such as age and comorbidities—are mainly what dictate what treatment we’ll choose,” says Delamo I. Bekele, M.D., a rheumatologist at the Mayo Clinic in Rochester, MN. “Sometimes, domains also overlap, so that’s an additional consideration that will affect which treatment we choose.”

Here’s a rundown of each domain, and what they might mean for your treatment options:

Joints

What it is: If your PsA mainly affects your joints—elbows, wrists, knees, ankles—but not your spine, it’s classified as peripheral arthritis.

How to treat it: The first line of defense, for minor cases, are anti-inflammatories (think ibuprofen or naproxen). After that, your doc may try steroid injections directly to the affected site. For moderate or severe cases, there are disease-modifying antirheumatic drugs (DMARDs) taken orally or via injection. “The only thing that we don’t recommend for peripheral PsA are oral steroids, because those haven’t been found to be very effective for treating the joints,” says Dr. Bekele.

Spine

What it is: Known as spondylitis or axial disease, this type of inflammation of the spine is less common, occurring in about 10% of patients, says Dr. Bekele. Although rare, “sometimes back pain can be the first symptom of psoriatic arthritis.”

How to treat it: If your condition is mild, your doctor will likely start you off with daily OTC anti-inflammatories. “Unlike with a standard headache where you’d take an anti-inflammatory as needed, with inflammation of the spine you need to take it consistently, and daily, to be effective,” says Dr. Bekele. Physical therapy is also typically part of the treatment plan. If those prove ineffective, your doc will skip over the disease-modifying medications—“those do not work for spine involvement,” says Dr. Bekele—and will instead turn to biologics, which are disease-modifying antirheumatic drugs that are injected.

Skin and Nails

What it is: What we most commonly think of with the name “psoriasis,” skin psoriasis is an inflammation of the skin and is characterized by a red, scaly rash typically on the elbows, knees, scalp and lower back. “Nail psoriasis usually coincides with skin psoriasis,” says Dr. Bekele, and includes pitting, crumbling, or spotting of the nails.

How to treat it: Get your dermatologist involved, suggests Dr. Bekele. “In addition to systemic medications that your rheumatologist will prescribe, there are also treatments that are driven by dermatology,” he says. Depending on severity, your derm may prescribe topical lotions, corticosteroids and, more rarely, ultraviolet therapy for extreme cases.

Tendons and Ligaments

What it is: You may not often think of enthesis—or even know what it is, for that matter!—until it acts up. Enthesis is where the tendons and ligaments attach to your bones, and inflammation of the area is called enthesitis. “It’s common to see psoriatic arthritis in the Achilles tendon or the plantar fascia on the bottom of the feet,” says Woodstock, New York-based podiatrist Doug Tumen, D.P.M., author of Ask the Foot Doctor. Other commonly affected areas are the hips and elbows.

How to treat it: “Enthesitis can be quite difficult to treat, but there are various options we use depending on how severe the symptoms are and also what part of the body is affected,” says Dr. Bekele. If your symptoms are mild, your doc will likely start you off with non-steroidal anti-inflammatories (NSAIDs) like ibuprofen or naproxen. For moderate or severe cases, disease-modifying medications like methotrexate are the next line of defense, followed by biologics. Localized steroidal injections can also work well for hips or elbows.

Toes and Fingers

What it is: “It’s called dactylitis, otherwise known as ‘sausage toe or finger,’ and it’s very common in psoriatic arthritis,” says Dr. Tumen. “Anytime I see a painful swollen toe, usually the third or fourth [the one next to the pinkie toe], I’m immediately going to suspect that it’s PsA,” he adds.

How to treat it: For mild cases, the typical protocol is to start off with anti-inflammatories. However, dactylitis can be slower to respond to treatment, says Dr. Bekele, so your MD will likely skip the disease-modifying antirheumatic drugs and go directly to biologics to treat it.

While PsA is a special, complicated disease, it can also be a manageable condition. “If you have a mild case, in time we can withdraw therapy or even stop it, but even if we can’t, at least we now have a better understanding of the different variables of the condition, so we can target therapy appropriately,” says Dr. Bekele.

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Megan McMorris