Psoriatic arthritis: Can biomarkers help predict flare-ups?

What is psoriatic arthritis?

Psoriatic arthritis (PsA) is an inflammatory condition that can affect anyone living with psoriasis. It often shows up as joint pain, swelling, morning stiffness, or tenderness where tendons attach. Symptoms can come and go, and flare-ups may feel unpredictable. PsA affects everyone differently, which is why early detection and personalised monitoring matter.

What is a biomarker?

A biomarker is a measurable sign of what’s happening inside the body. It can be something found in the blood, something seen on an imaging scan, or even a pattern in your genes. When it comes to PsA, biomarkers are used to detect inflammation, monitor how active the disease is, and sometimes predict when a flare-up might be on the horizon.

Blood-based biomarkers

Blood tests are often the first tool doctors use to look for signs of inflammation:

C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR)

CRP and ESR are two of the most common tests. They go up when there’s inflammation in the body. But here’s the catch: in psoriatic arthritis, up to 60% of people may have normal CRP or ESR levels even during a flare. So while they’re helpful for some, they aren’t reliable for everyone.

Calprotectin

Calprotectin is a newer marker that reflects immune cell activity. High levels of calprotectin in the blood have been linked to more active joint inflammation in PsA. It’s not yet a routine test in every clinic, but it’s gaining attention as a more sensitive tool, especially when traditional markers are normal.

Cytokines

Cytokines like TNF-alpha, IL-17, and IL-23 are key messengers in the immune system. They’re often elevated during flares, but testing for them directly is mostly done in research settings for now.

Imaging biomarkers

Sometimes, the best way to see inflammation is to literally see it:

Ultrasound

Ultrasound can detect joint swelling, fluid buildup, and increased blood flow in the tissues, which are signs of a flare. It’s more sensitive than a physical exam and can pick up inflammation even if you’re not feeling severe symptoms.

MRI

MRI is another powerful tool, especially useful if PsA affects your spine or pelvis. It can show bone inflammation and early joint changes before they appear on X-rays. Doctors might recommend it when symptoms are unclear or if you’re not responding to treatment.

These imaging tools aren’t used daily, but they’re becoming more common, especially in specialized clinics.

Genetic and epigenetic markers

Genetic traits don’t change during a flare, but they can influence how psoriatic arthritis shows up and progresses:

HLA-B27

HLA-B27 is a gene found more often in people whose PsA affects the spine. Testing positive doesn’t mean you will flare more often, but it can help doctors understand your disease pattern.

MicroRNAs

These are tiny molecules that help regulate gene activity. Some studies show people with PsA have different microRNA patterns compared to those with only skin psoriasis. This research is still early, but it could one day help identify who’s at risk for developing PsA, or predict flares more precisely.

What’s on the horizon?

Researchers are digging deeper into the body’s response during a flare-up, and they’ve found some promising leads:

Protein fragments from tissue breakdown

Bits of protein, such as collagen or vimentin, seem to rise in the blood during PsA flares. These are signs that joints and surrounding tissues are actively inflamed or being damaged. Some of these markers, like degraded calprotectin, are showing strong potential in research settings.

Multi-marker panels

Instead of relying on one lab test or scan, combining several biomarkers, like blood proteins, imaging findings, and even genetic patterns, could give a fuller picture of what’s happening in the body. Think of it as a flare “scorecard” that doctors could use to tailor treatment more precisely.

Why it matters

Right now, PsA management often depends on how you're feeling and what the doctor sees during an exam. But symptoms can be subtle, and inflammation can simmer under the surface. With better biomarkers, flares could be detected earlier, possibly even before symptoms start, and treatment could be adjusted before things worsen. That means fewer surprises, more control, and potentially better long-term outcomes.

Key takeaways

• CRP and ESR are helpful, but not always reliable in PsA
• Calprotectin and imaging like ultrasound or MRI may catch flares that other tests miss
• Genetics and microRNAs may one day help predict flares or disease progression
• New biomarkers from tissue breakdown and inflammation are emerging fast

As always, it’s important to work closely with your rheumatologist. Biomarker testing is only one piece of the puzzle, but it’s a piece that’s becoming more powerful as research continues to grow.

If you’ve noticed flares without clear triggers or if your tests don’t seem to reflect how you feel, it’s worth talking to your care team about whether newer biomarker tools could help guide your treatment.

If you found this article helpful, feel free to give it a “Like” and share your thoughts and questions with the community in the comments below!

Take care!