Busting the science behind PsA

What is psoriatic arthritis (PsA)? Sorry-attic what?!! As someone living with PsA, you probably have countless answers to that question. But what’s really happening on the inside? Let’s take a peek at the science behind our symptoms.

About 40% of people with psoriasis will encounter its nasty cousin PsA within 5 to 10 years of psoriasis first appearing. That said some people get PsA before any redness or cracks appear or without ever having experienced psoriasis at all.

What’s going on inside the body?

Hands-up, it’s not fully understood what exactly causes PsA. Or what’s happening at a molecular level (that’s when scientists look at the very basic nuts and bolts of how our cells are built and work). One reason being it’s still really hard to study what’s going on inside joints. Still, here’s what we do know…

Let’s start with what PsA is not. PsA is a condition in its own right and not just another symptom of psoriasis. Mostly PsA comes with psoriasis symptoms, but not always. Huh?!! Let’s think of psoriasis and PsA as being cousins – mean and nasty cousins – but not twins. They don’t always come as a pair, but are related.

Psoriasis and PsA actually play the same mean tricks on your body and its immune system; one does it to your skin and the other to your joints.

They do this by triggering the immune system to protect the body against ‘invaders’. T-cells, a type of white blood cell, have the job to hunt down things like bugs or bacteria. But here’s where it gets interesting. In PsA there are no invaders. Zilch. Nada. So our T-cells mistakenly attack healthy cells. Redness and inflammation appear. It’s thought this ‘friendly fire’ hits other parts of the body, leading to PsA flare-ups and joint pain.

But why do some people with psoriasis get to dodge the bullet, while others add PsA to their list of ailments? There’s no hard and fast rule for this. Instead, a mix of factors like physical trauma or infections and our genes seem to trigger the body’s attack of healthy tissue and cells in PsA.

These triggers start a chain reaction something like this: T-cells set off around the body with the help of Th17 cells (the ‘Th’ stands for T-helper). Th17 allows T-cells to enter the joints. In fact, studies show that people with PsA have higher levels of Th17 cells in their blood and the “oil” in their joints (aka synovial fluid) .

Phew! A whistle stop tour of the inside out of PsA…

To help keep ahead of the what’s going on inside, always keep an eye on your symptoms and chat to your physician about any changes to keep these naughty cousins in check.

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Find Support

Psa and Me isn’t the only place to get good advice about living with psoriatic arthritis. There are various PsA charities and support groups out there – both online and across the globe.

Learn More