If you have joint pain on the left side of your body, it could mean you have a type of arthritis in which symptoms appear on just one side instead of both sides. This is known as asymmetric arthritis. Psoriatic arthritis, or PsA, is one of those types of arthritis. In a study of 126 patients with PsA, 53.1% of people who had PsA symptoms experienced them on just one side of their bodies.

Common Causes of Left Side Joint Pain

Maybe you’ve noticed more swelling, tenderness, and painful sensations on the left side of your body in small or large joints. PsA can attack many joints or just a few, and this can also change as the disease progresses.

What Is Psoriatic Arthritis?

PsA is an inflammatory form of arthritis linked to the autoimmune disease psoriasis, which can cause itchy, scaly patches of skin. PsA can sometimes develop in people without psoriasis, but it occurs prior to or with psoriasis around 85% of the time. PsA may also begin in childhood. 

For example, you may start with left side joint pain in your wrist, knee, or the sole of your foot. This may later progress to left side joint pain in the sacrum area, from the top of your spine to the base of your lower back, or tailbone. 

Scientists think that genes and environmental triggers like experiencing a trauma or contracting a virus may play roles in whether a person develops PsA and how often they experience joint pain from flare-ups. 

What Is a Flare?

A flare, or flare-up, refers to an increase in symptoms of any disease. To have a PsA flare-up means to experience the characteristic symptoms of joint pain, swelling, and stiffness with or without psoriasis symptoms.

Psoriasis 

It’s estimated that 20%–30% of all patients with psoriasis will develop PsA. Does that mean psoriasis causes psoriatic arthritis? Not exactly, no. The cause is more often related to immune system dysfunction happening throughout your body.

Common Causes Explained

  • PsA can be triggered by a physical trauma, infection, or severe stress.Injuring your skin can trigger a psoriasis flare in the area.Certain medications may trigger a PsA flare.Bacterial infections like strep throat can trigger a PsA flare.Having certain inherited gene combinations make a person more likely to develop PsA.

PsA can also attack your organs. It’s considered an autoimmune disorder because your body mistakenly begins attacking healthy tissues, but it’s not really known why this happens in some people.

Genetics

PsA gene research is ongoing. Here’s what scientists know so far:

  • There are genetic differences between psoriasis and PsA.Certain genetic coding variants (gene differences, or mutations) are linked with and may be strongly associated with PsA (TYK2 and TRAF3IP2).Your genes can be used to predict treatment outcomes for PsA.

Exacerbating Factors 

While these are not causes of PsA, you will notice that certain habits or lifestyle choices have a serious impact on both your skin condition (psoriasis) and joint inflammation (arthritis). 

Here are some of the most common exacerbating factors and how to cope. 

Dry skin

Dry skin can contribute to an increase in PsA skin symptoms like itching, scaling, and peeling or flaking. 

Keeping your skin moisturized with gentle products (scent-free or plant-based natural options free of potential skin irritants). 

Fragrances and Dyes

While your apple orchard– or rain forest–scented laundry detergent may make your blankets and clothes smell clean, they can also irritate the sensitive skin that comes with having psoriasis or PsA. 

Moisturizing Tips

  • Use aloe, jojoba, and zinc to protect your skin.Take short, warm baths with Epsom salts, oatmeal, and pure (fragrance- and perfume-free) bath oils.Moisturize daily and after any water-based activities (bathing, showering, swimming).Rub body oil into your skin when it’s still wet and spread the oil over larger areas of skin, like your legs, arms, chest, and back of the shoulders.

Choose the dye- and scent-free options when it comes to:

  • Hand soap, body wash, bubble bathFace care products, including makeupLaundry detergentLotions, creams, and sunscreenAir fresheners (droplets can land on clothing, furniture, blankets)

High stress 

Stress is a part of life, but it’s also a culprit contributing to symptom flare-ups. This includes left side joint pain that can make getting out and relieving stress a little more challenging. If you find some activities too difficult with your left side joint pain, make adjustments so that you can continue to engage in stress-relieving activities. 

Other lifestyle factors may also play a role in developing PsA symptoms. An analysis conducted in 2020 found the following risk factors were associated with increased flares in patients with psoriasis:

Don’t Let Stress Lead to Withdrawal

People with PsA may be prone to social withdrawal and isolation when stressed and when having flare-ups. Try adding some activities that include socializing with others or at least being around others, such as group walks, dinner with friends, or going to a theater. 

  • ObesityHistory of physical trauma

However, the following did not have a significant impact:

  • Alcohol consumptionSmoking statusFemale hormone exposure and levelsPsychologically traumatic events

You can help reduce your risk of PsA and symptom flare-ups, including left side joint pain in your fingers, knee, or shoulder, by maintaining a healthy weight and preventing injuries. 

A Word From Verywell

If PsA runs in your family, there is a chance you will get it too, but a genetic link doesn’t automatically mean you will develop this autoimmune disease. If you do experience PsA, know that it’s due to factors that are largely outside of your control, including your genetic makeup and certain uncontrollable environmental factors.

You do, however, have a lot of control over how PsA impacts your everyday life. Making some minor changes like keeping your skin hydrated and protected can make a large difference in symptom severity and flare-up frequency. If you’re concerned, talk to your doctor or other medical professional about ways you can reduce the risk of damage and injury to your joints.