Causes of Psoriatic Arthritis: Triggers and Risk Factors

Psoriatic arthritis (PsA) is a chronic autoimmune disease that affects both the skin and joints. While it often develops in people who already have psoriasis, not everyone with psoriasis will develop PsA. Understanding what causes psoriatic arthritis—and the triggers and risk factors involved—can help with early detection and management.

What Causes Psoriatic Arthritis?

Psoriatic arthritis occurs when the body’s immune system mistakenly attacks healthy joints and skin, leading to inflammation, pain, and swelling. Although the exact cause isn’t fully understood, researchers believe PsA develops due to a combination of genetic, environmental, and immune system factors.

Genetic Factors

Your genes play a big role. If someone in your family has psoriasis or psoriatic arthritis, your risk increases significantly.

• Family history: Up to 40% of people with PsA have a close relative with psoriasis or arthritis.
• HLA-B27 gene: This gene is commonly found in people with PsA, especially those who have spinal involvement.

Environmental Triggers

Certain external factors can trigger the onset of PsA—especially if you’re already genetically predisposed.

• Infections: Strep throat or other bacterial/viral infections may activate the immune system in harmful ways.
• Injury: A physical injury or trauma (known as the Koebner phenomenon) may trigger a flare-up of psoriasis or PsA symptoms.
• Stress: High levels of emotional or physical stress may worsen or trigger autoimmune responses.

Immune System Malfunction

In PsA, the immune system goes into overdrive and starts attacking the body's own tissues. This causes chronic inflammation, which leads to joint pain, swelling, and damage over time.

Risk Factors for Psoriatic Arthritis

Several factors can increase your risk of developing PsA:

Psoriasis

• The single biggest risk factor for PsA is having psoriasis.
• Nail changes like pitting or separation are especially linked to PsA.

Age

• PsA usually develops between ages 30 and 50, but it can occur at any age.

Obesity

• Excess weight can increase inflammation and put extra stress on joints, raising the risk of PsA.

Smoking

• Tobacco use is linked to more severe psoriasis and a higher risk of developing PsA.

Gender

• Men and women are affected equally, but the pattern of symptoms may vary.

Final Thoughts

While psoriatic arthritis can be unpredictable, knowing its causes and risk factors helps with early intervention. If you have psoriasis and experience joint pain, stiffness, or swelling, speak with a healthcare professional. Early diagnosis and treatment are key to preventing long-term joint damage and improving quality of life.