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Psoriasis vs Psoriatic Arthritis: What’s the Difference?

Psoriasis on elbow

While psoriasis and psoriatic arthritis are chronic autoimmune conditions, there are certain lifestyle modifications that can reduce the likelihood for flare-ups.

Here I discuss how psoriasis and psoriatic arthritis are related, the risk factors that contribute to disease, and various treatment options. 

What is Psoriasis?

Psoriasis is an autoimmune skin disorder characterized by red patches covered with thick silvery scales. The most common form of psoriasis is plaque psoriasis, with lesions most commonly found on elbows, knees and scalp. Other forms of psoriasis include guttate psoriasis, pustular psoriasis and inverse psoriasis.

What is Psoriatic Arthritis? How is it linked to Psoriasis?

Psoriatic arthritis is an autoimmune disorder characterized by inflammation of the joints, and occasionally the spine. Patients with psoriatic arthritis typically present with joint pain, swelling and prolonged AM stiffness. Patients may also have inflammatory low back pain, which improves, rather than worsens, with activity. This is different from mechanical low back pain, which worsens with activity. Enthesopathy, or inflammation at the sites where tendons and ligaments attach to the bone, is another key feature of psoriatic arthritis. Achilles tendonitis and plantar fasciitis are examples of enthesopathy. Dactylitis (“sausage digit”), nail changes, and eye inflammation are also associated with psoriatic arthritis.

What is the likelihood of a patient developing psoriatic arthritis? What are the risk factors?

Psoriatic arthritis affects up to 25 percent of patients with psoriasis, although the incidence has been estimated to be higher (around 20–40 percent) in patients with more extensive skin disease. The majority of patients have psoriasis at the onset of their arthritic symptoms, but some may develop skin disease well after the arthritis has presented. Some patients with psoriatic arthritis may never develop psoriasis, but they may have a family history of psoriasis or psoriatic arthritis. Obesity during early adulthood and HIV have also been identified as risk factors. In patients with psoriasis, the severity of psoriasis, the presence of nail pitting and uveitis have been correlated with an increased risk developing psoriatic arthritis.

What are the current treatment options for patients who suffer from both conditions?

Methotrexate is a traditional disease modifying agent that is effective in both psoriasis and psoriatic arthritis. Patients with severe psoriasis and/or psoriatic arthritis are often treated with biologic agents, such as anti-tumor necrosis factor inhibitors [anti-TNFs], ustekinumab, and secukinumab. There are newer oral medications such as apremilast and tofacitinib that have both been approved for psoriatic arthritis, but tofacitinib has not yet received FDA approval for plaque psoriasis.

Are there any lifestyle modifications that I can make?

Absolutely. Several lifestyle modifications have been shown to be beneficial in psoriasis and psoriatic arthritis patients, including weight loss, routine exercise, and avoidance of smoking and excessive ETOH consumption.

Dr. Dee Dee Wu, rheumatologist

Dr. Dee Dee Wu is a rheumatologist who specializes in the treatment of rheumatoid arthritis, psoriatic arthritis, osteoarthritis and osteoporosis. She practices at both the HSS Outpatient Center in Paramus and the hospital’s main campus in New York.

The information provided in this blog by HSS and our affiliated physicians is for general informational and educational purposes, and should not be considered medical advice for any individual problem you may have. This information is not a substitute for the professional judgment of a qualified health care provider who is familiar with the unique facts about your condition and medical history. You should always consult your health care provider prior to starting any new treatment, or terminating or changing any ongoing treatment. Every post on this blog is the opinion of the author and may not reflect the official position of HSS. Please contact us if we can be helpful in answering any questions or to arrange for a visit or consult.