Skin & Bones

What causes psoriatic arthritis?

YOUR IMMUNE SYSTEM AND INFLAMMATION

Psoriatic arthritis, like psoriasis, is an autoimmune condition. That means both are caused by your immune system. When your immune system turns itself on automatically and starts attacking healthy cells and tissues instead of battling bacteria and viruses, the result can be the inflammation common in both conditions. In psoriasis, this inflammation happens in the skin, and in psoriatic arthritis this inflammation leads to swollen and painful joints and tendons.

Psoriatic arthritis, like psoriasis, is an autoimmune condition. That means both are caused by your immune system. When your immune system turns itself on automatically and starts attacking healthy cells and tissues instead of battling bacteria and viruses, the result can be the inflammation common in both conditions. In psoriasis, this inflammation happens in the skin, and in psoriatic arthritis this inflammation leads to swollen and painful joints and tendons.

 

Unfortunately, researchers still don’t know exactly what triggers autoimmunity, or even how it works.

 

What is clear, however, is that the process is similar to how the body responds to real invaders: it tries to get rid of them by using a type of immune cell, called T-cells, to begin an inflammatory attack. When you’re sick or injured, this is a good thing, as it triggers inflammation and causes blood vessels to expand. For people with psoriasis, this unwelcome attack results in red, itchy and scaly patches on the skin, and for those with psoriatic arthritis, pain and stiffness in the joints.

Your immune system isn’t always helpful.

When the “soldiers” go haywire

In this video, Josiane Soucy Larocque, RN, explains the immune system’s role in psoriatic arthritis with an imaginative analogy she uses to help her patients understand the process.

The genetic connection

There is little doubt that psoriasis and psoriatic arthritis have a genetic component, and they are therefore more likely to occur in people with affected family members. In fact, about 40% of people with psoriasis or psoriatic arthritis have family members with one of the conditions. A close relative of someone with psoriatic arthritis is about 50 times more likely to develop psoriatic arthritis than someone who is not related.

There is little doubt that psoriasis and psoriatic arthritis have a genetic component, and they are therefore more likely to occur in people with affected family members. In fact, about 40% of people with psoriasis or psoriatic arthritis have family members with one of the conditions. A close relative of someone with psoriatic arthritis is about 50 times more likely to develop psoriatic arthritis than someone who is not related.

 

Recent research has discovered certain genetic markers that appear to be associated with psoriatic arthritis. This could help to explain how the condition passes from parents to children.

 

Variations in several genes have also been associated with psoriatic arthritis, and many of them have been thought to play a role in how the immune system works. Overall, however, researchers believe these particular genes likely have only a small effect on the chances of someone developing the condition. More research is necessary to determine the other genetic and environmental factors that play greater roles.

Your family can help in more ways than one

In this video, Dr. Nancy Maltez explains how your family’s medical history is also a valuable tool for diagnosing psoriatic arthritis.

Having a close relative with PsA makes you ~50x more likely to develop the condition.