The Mystery of Psoriatic Arthritis — Is It Caused by Psoriasis?

New research results help doctors manage condition

The Mystery of Psoriatic Arthritis -- Is It Caused by Psoriasis?

While psoriasis and psoriatic arthritis (PsA) have previously been thought to affect only the skin and joints, research in the past few decades has shown that psoriatic disease can impair the entire body, from the inside out. As an autoimmune disorder, psoriatic disease causes cells in your body to attack other cells.

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Dermatologist Anthony Fernandez, MD, PhD, says psoriasis is a systemic disease and psoriatic arthritis can progress quickly. Without early treatment, it can cause significant and irreversible damage to your bones and cartilage.

Researchers initially believed that psoriatic arthritis was an outgrowth of psoriasis. However, recent findings have identified a gene directly linked to PsA that isn’t present in individuals who only have psoriasis. Testing for this gene will help doctors identify who will likely develop PsA and help them start effective treatments earlier.

Busting psoriatic arthritis myths

Recent investigations also reveal that the risk of developing PsA does not decrease over time for those who have psoriasis. Doctors previously believed that if PsA didn’t appear within 10 years of a psoriasis diagnosis it wouldn’t occur at all. Research now shows that’s incorrect.

Ultimately, Dr. Fernandez says, identifying PsA as soon as possible is the key to successfully managing it.

“Early diagnosis is important to maximize chances that the proper medications are started,” he says. “That will protect quality of life and joint function.”

Related: How to Deal If Your Psoriasis Leads to Psoriatic Arthritis

Symptoms often slow to show

According to Dr. Fernandez, the majority of people who develop psoriatic arthritis have psoriasis first.

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Up to 30 percent of people with psoriasis will develop PsA, but it can take an average of 10-12 years to show up. Researchers have yet to discover why the systemic condition takes so long to appear, he says.

Related: 11 Conditions You Can Develop If You Have Psoriatic Arthritis

Treatments target markers in your blood

Generally, dermatologists treat mild psoriasis in patients without PsA with topical creams or phototherapy that only penetrate the top skin layers.

However, If you have PsA and/or moderate to severe psoriasis, pills or injected medications are needed to control systemic inflammation.

PsA, in particular, may be associated with elevation of markers in your blood that reveal potential inflammation in your joints. PsA requires pills or injected medications — often steroids called glucocorticoids — to control the inflammation in your joints and throughout the body.

“Topical medications have no way to control systemic inflammation,” Dr. Fernandez says. “That’s why pills and injectables are so important. They can access the bloodstream and can reduce inflammation all over the body.”

While glucocorticoids are a help, injecting them can carry a small risk of serious joint infection. Your doctor will likely screen for active infections or a history of frequent infections when deciding whether to use this therapy.

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Some pills may stimulate liver inflammation. They can also reduce blood counts or impair kidney function, he says.

Signs to watch for

Some of the symptoms of PsA are similar to those of osteoarthritis and rheumatoid arthritis.

If you have psoriatic arthritis, you could experience:

  • Joint swelling
  • Tenderness
  • Limited range-of-motion
  • Stiffness

Psoriatic arthritis also can be associated with silver-grey scaly spots on elbows, knees, scalp and lower back. Pitting and detachment of fingernails and toenails is another sign.

If you see these signs, alert your dermatologist. He or she can tell you whether you should see another specialist, such as a rheumatologist.

Related: 6 Things Your Nails Can Say About Your Health