What Is Psoriatic Arthritis? 3 MDs Weigh In

What is psoriatic arthritis?
Photo Illustration by Keila Gonzalez
Photo Illustration by Keila Gonzalez

This informational guide, part of POPSUGAR's Condition Center, lays out the realities of this health concern: what it is, what it can look like, and strategies that medical experts say are proven to help. You should always consult your doctor regarding matters pertaining to your health and before starting any course of medical treatment.

Psoriasis affects about three percent of American adults, but the disorder can raise the risk of having more than skin scales and plaques. About 30 percent of people with psoriasis will develop psoriatic arthritis, a painful condition that can cause joint swelling and stiffness.

Doctors aren't entirely sure why some people with psoriasis go on to develop psoriatic arthritis, but the condition can have a big impact on daily life. Psoriatic arthritis is sometimes diagnosed before psoriasis, making it important to have symptoms of both conditions on your radar. Here's what psoriatic arthritis is, as well as how it's diagnosed and treated.

What Is Psoriatic Arthritis?

Psoriatic arthritis is a "chronic inflammatory disease that occurs when your immune system mistakenly starts attacking healthy joints and skin," says Jennifer Gurske-dePerio, MD, a clinical assistant professor in the University at Buffalo's orthopedics department. It can cause severe joint inflammation and it usually happens along with psoriasis, adds Orrin Troum, MD, a rheumatologist at Providence Saint John's Health Center in Santa Monica.

Psoriatic arthritis can range from mild to severe, and it may lead to significant joint damage and disability if not treated properly, explains Paras Karmacharya, MD, the director of the Vanderbilt Psoriatic Arthritis and Spondyloarthritis Center.

Types of Psoriatic Arthritis

Psoriatic arthritis is usually broken down into five types. According to Dr. Troum, those include:

  • Distal interphalangeal predominant: This mainly affects the joints at the ends of the fingers and toes, with symptoms that can include nail changes.
  • Asymmetric oligoarticular: This form of psoriatic arthritis involves different joints on each side of the body.
  • Symmetric polyarthritis: The same joints on each side of the body are impacted in this form.
  • Spondylitis: This type involves inflammation in the joints between the vertebrae in the spine.
  • Arthritis mutilans: This is the most severe form of psoriatic arthritis, and it involves severe inflammation that damages the joints in the hands and feet.

Psoriatic Arthritis Symptoms

Symptoms of psoriatic arthritis can vary from person to person, but they generally include the following, according to Dr. Karmacharya:

  • Scaly, inflamed patches of skin
  • Joint stiffness, pain, and swelling
  • Fatigue
  • Tenderness in areas where tendons or ligaments attach to bones, like the achilles tendon at the heel
  • Painful swelling of a whole finger or toe
  • Nail pitting or crumbling
  • Eye inflammation
  • Inflammatory bowel disease

What Causes Psoriatic Arthritis?

The cause of psoriatic arthritis isn't clear, but experts have a few hypotheses and thoughts surrounding risk factors and potential causes, including:

  • The immune system: "While the exact cause of psoriatic arthritis is unknown, an overactive immune system can cause inflammation inside the body," Dr. Gurske-dePerio says. "This immune response can make your joints stiff and sore, which are common symptoms associated with psoriatic arthritis."
  • Genetics: Given that people with a family history of psoriatic arthritis are at a higher risk of developing it themselves, there also seems to be a genetic component associated with the condition, per Dr. Troum.
  • Certain preexisting conditions: Conditions like depression and thyroid disease are also linked with psoriatic arthritis, Dr. Karmacharya tells PS.

"Factors such as physical or emotional stress, injury to the skin, infections, and possibly certain drugs may trigger the onset of psoriatic arthritis in genetically susceptible individuals," Dr. Karmacharya adds. This includes those with a family history of psoriasis or certain genes associated with psoriasis. But ultimately, having psoriasis remains "the most significant risk factor for developing psoriatic arthritis," he says.

How Is Psoriatic Arthritis Diagnosed?

Diagnosing psoriatic arthritis can be challenging, and there are no blood tests or other single diagnostic tests for the condition, per Dr. Karmacharya.

When you see a doctor, they'll usually ask questions about your health and examine your skin, scalp, and nails, Dr. Gurske-dePerio says. "Your healthcare provider then might take a small sample of skin for examination under a microscope. This helps determine the type of psoriasis and rule out other disorders."

Other diagnoses like rheumatoid arthritis, gout, or infection may need to be ruled out with a combination of your medical history, an exam from your doctor, and lab work, per Dr. Gurske-dePerio.

How Is Psoriatic Arthritis Treated?

There is no cure for psoriatic arthritis. Treatment typically centers around pain management and depends on the severity of the condition. For milder forms of psoriatic arthritis, medications like over-the-counter anti-inflammatory and pain medications can help to treat pain and swelling, while corticosteroid injections can help tamp down on inflammation in the joints, Dr. Troum tells PS.

For more severe forms of the disease, disease-modifying antirheumatic drugs (DMARDs) and biologics can help suppress the immune system and lower side effects of the condition, per Dr. Troum.

Ultimately, "each patient is different and has different risk factors to consider," Dr. Gurske-dePerio explains.

Korin Miller is a writer specializing in general wellness, health, and lifestyle trends. Her work has appeared in Women's Health, Self, Health, Forbes, and more.