Psoriatic arthritis is a progressive, inflammatory condition that affects your joints and areas of the body where connective tissue meets bone.

Because psoriatic arthritis is tied to your immune system function, it’s often referred to as an autoimmune disease.

Subtle differences exist, however, between what makes a condition autoimmune versus immune-mediated. Psoriatic arthritis may fall more into the immune-mediated category than autoimmune.

Psoriatic arthritis is often labeled as an autoimmune disease, but it may be best described as an immune-mediated disease with autoimmune features.

Autoimmune diseases occur when your body’s immune system mistakenly attacks healthy tissues, directly causing damage, inflammation, and cellular degeneration.

Rheumatoid arthritis is an example of an arthritic condition considered autoimmune. In rheumatoid arthritis, the immune system targets the lining of the joints, also called synovium.

Immune-mediated diseases are similar to autoimmune conditions. They’re also caused by an abnormal immune response that leads to inflammation, but they don’t necessarily involve a direct attack against your healthy tissues.

In immune-mediated conditions, immune system dysfunction causes a state of inflammation that has indirect effects on certain areas of the body, such as your joints.

According to research from 2021, psoriatic arthritis has autoimmune and auto-inflammatory properties but is best described as immune-mediated.

Rather than a direct immune attack on healthy tissues, psoriatic arthritis appears to have complex underlying genetic and environmental mechanisms that cause alterations in the immune system. These immune system changes then create a state of inflammation that affects the skin and joints.

The exact causes of psoriatic arthritis aren’t clear. Genetics and environmental factors — such as smoking, obesity, and trauma — are thought to play a role in dysfunction in the immune system, leading to psoriatic arthritis.

Symptoms of psoriatic arthritis include:

  • fatigue
  • swelling and tenderness over tendons
  • joint inflammation, throbbing, stiffness, and pain
  • morning stiffness
  • reduction in range of motion
  • pain and redness of the eye
  • nail pitting or separation from the nail bed
  • inflammatory bowel disease
  • finger or toe swelling
  • scaly, inflamed patches of skin

Treatment for psoriatic arthritis depends on the severity of your symptoms and how negatively they affect your day-to-day life.

In mild cases, over-the-counter (OTC) anti-inflammatory medications and corticosteroid injections can help ease inflammation and manage discomfort.

If you live with moderate to severe psoriatic arthritis, your doctor may prescribe biologic response modifiers, medications that disrupt specific signals in your immune system.

You may also benefit from disease-modifying anti-rheumatic drugs, medications that create body-wide immune suppression, such as methotrexate.

Lifestyle changes, such as quitting smoking, may also be recommended.

Does psoriasis cause psoriatic arthritis?

Psoriasis isn’t a direct cause of psoriatic arthritis. These conditions are separate, though they appear to share a number of genetic components and risk factors.

What’s the root cause of psoriatic arthritis?

The root cause of psoriatic arthritis is unclear. Genetics and environmental factors may contribute to immune system dysfunction that produces pain and inflammation.

What autoimmune disease goes with psoriatic arthritis?

Psoriatic arthritis is often associated with psoriasis because these conditions commonly occur together and appear to share genetic features and risk factors.

Psoriasis and psoriatic arthritis are not the same, however. Psoriasis is another immune-mediated condition sometimes referred to as an autoimmune disease.

Does psoriatic arthritis make you immunocompromised?

Psoriatic arthritis doesn’t suppress your immune system, but some of the medications used to treat psoriatic arthritis can cause you to become immunocompromised.

How serious is psoriatic arthritis?

Psoriatic arthritis can range in severity from mild to severe. Treatment is recommended at all stages to prevent permanent joint damage and reduce inflammation in the body that may lead to other chronic health challenges.

Psoriatic arthritis is a progressive condition that causes skin and joint inflammation and pain. While it’s commonly seen alongside the skin disease psoriasis, psoriatic arthritis is its own diagnosis.

Sometimes referred to as an autoimmune disease, psoriatic arthritis isn’t caused by a direct immune system attack on your joints. It’s thought to stem from dysfunction in the immune system, which creates inflammation in the body. For this reason, psoriatic arthritis may best be described as an immune-mediated condition.

While there’s no cure for psoriatic arthritis, medications can help manage your symptoms and prevent permanent joint damage.