PsA versus RA: What’s the Difference?
Psoriatic arthritis (PsA) and rheumatoid arthritis (RA) are two conditions that can often go hand in hand. This isn’t because they are mirror images of each other—on the contrary, there are several key differences between the two—but rather, is usually due to a lack of knowledge on what sets them apart. While there are many overlaps between them, their differences can be very distinct, if you know what to look for. Let’s take a look at some of the major similarities and differences between these two common, and frustrating, conditions!
Similiarities between conditions
Taking a large step back, these two could be completely indistinguishable, leading to much confusion. It isn’t until we really scrutinize what someone is going through on a daily basis, that we can really tell them apart. From a further away standpoint however, both PsA and RA possess many of the same defining features:
- Both PsA and RA are auto-immune conditions: This means that the body mistakenly attacks its own healthy cells in both conditions. This is why individuals with RA and PsA both experience erosive joint symptoms, such as swelling, pain, and stiffness, as well as chronic fatigue from an immune system working in overdrive.
- Both affect internal organs: Long-term progression of both PsA and RA can lead to scarring, inflammation, and damage to major internal organs, such as the heart and lungs. This process is incredibly similar in both!
- Accompanying osteoporosis: Both PsA and RA can lead to a weakening of bones, otherwise known as osteoporosis. This can make additional fracturing of bones or joints incredibly easy for individuals with PsA and RA.
- Similar treatment algorithms: Treatment of RA and PsA can be virtually identical at times, and include anti-inflammatory medications (NSAIDS), corticosteroids, DMARDS (disease modifying anti-rheumatic agents), and even surgery to stabilize affected joints in serious cases.
Differences between conditions
Although on a large scale these two couldn’t be more similar, when taking a closer look, their differences couldn’t be more apparent. Many of these differences act on a more daily level, as opposed to the condition’s progression as a whole, and can be very distinguishing factors.
- Blood test results: One common difference between PsA and RA comes on the microscopic blood level. Oftentimes, individuals with RA will have an antibody present in their blood known as rheumatoid factor. Therefore, to any medical provider, blood tests for these conditions can be very different!
- Specific joints affected: Although joint pain, swelling, and stiffness are common symptoms in both conditions, the specific joints affected can be extremely indicative of one over the other. For example, PsA often affects distal joints in the fingers and toes (meaning the joints closest to the nail bed), and in the lower back. This can lead to the appearance of “sausage fingers or toes.” Conversely, RA tends to affect a different set of joints, such as those in the middle of fingers and toes, as well as at the wrist. Additionally, joint pain with PsA is typically asymmetrical versus the more uniform RA.
- PsA affects much more than just joints: While both conditions have wide-reaching, and debilitating symptoms, PsA can often go beyond just bones to affect tendons, skin, nails, and even the eyes. This can lead to a wide host of related conditions, such as plantar fasciitis, conjunctivitis of the eye, and most commonly, psoriasis of the skin. Although one doesn’t have to have psoriasis to have PsA, it is a very common comorbidity.
On the whole, PsA and RA can look extremely similar, especially to an unknowing observer. However, on a smaller scale, they can present completely different! The key to being able to distinguish between the two yourself, or helping others learn the differences, often can come from education about each. It may take time, and it often isn’t clear-cut at all, but knowing what differences to look for can be incredibly helpful!
- Martin, Layne. “What is the difference between psoriatic arthritis vs. rheumatoid arthritis?” CreakyJoints.org. Available from: https://creakyjoints.org/blog/psoriatic-arthritis-differ-rheumatoid-arthritis/.
- “Psoriatic Arthritis.” Alberta Rheumatology. Available from: http://albertarheumatology.com/inflammatory-arthritis/psoriatic-arthritis/.