Knowing the difference between psoriatic arthritis, osteoarthritis, gout and rheumatoid arthritis can get challenging, especially when so many symptoms and causes overlap. Arthur Mandelin, M.D., Ph.D., an NPF medical board member and a rheumatologist at Northwestern University Feinberg School of Medicine in Chicago, helps clear up any confusion.
Psoriatic Arthritis
Doctor’s notes: In simplest terms, psoriatic arthritis (PsA) is a disease in which the body’s immune system attacks healthy cells, specifically in the joints. About a third of people with psoriasis also develop PsA sometime in their lifetime. While PsA shares similarities with rheumatoid arthritis, osteoarthritis and gout, it is dissimilar, especially in the case of gout and osteoarthritis.
“Psoriatic arthritis is a disease,” says Mandelin. “Something is going on in the body that shouldn’t be going on, making the person ill and driving inflammation and the arthritic process.”
Rheumatoid arthritis and PsA share many similarities, as they are both caused by issues in the immune system. However, one of the ways in which PsA differs from rheumatoid arthritis is that it can affect the spine, where RA rarely strikes, Mandelin explains.
One major similarity between PsA and rheumatoid arthritis is how they are handled. For the most part, the two have similar treatment options (biologics, oral treatments, non-steroidal anti-inflammatory drugs, etc.) and the trial-and-error process to find what works best for each individual.
Symptoms
- Swelling and pain in the joints
- Limited range of motion
- Tenderness and pain in the tendons (fibrous tissue that attaches muscle to bone)
- Morning stiffness and general fatigue
- Pain in the eyes and redness of the cornea
Treatment Options
- Biologics and biosimilars
- Oral treatments
- Non-steroidal anti-inflammatory drugs
- Disease-modifying anti-rheumatic drugs
Rheumatoid Arthritis
Doctor’s notes: Of all the joint diseases, rheumatoid arthritis is the most similar to PsA and operates in the same fashion – the body’s immune system attacks healthy tissue. The biggest distinction between PsA and rheumatoid arthritis is that, while PsA is usually accompanied by psoriasis, there is no visible skin condition associated with rheumatoid arthritis.
Symptoms
- Swelling and pain in the joints
- Limited range of motion
- Tenderness and pain in the tendons
- Morning stiffness and general fatigue
Treatment Options
- Biologics and biosimilars
- Oral treatments
- Non-steroidal anti-inflammatory drugs
- Disease-modifying anti-rheumatic drugs
Gout
Doctor’s notes: While gout shares some similarities with PsA, the way in which the disease functions is quite different. “For gout, there is a very clear trigger,” Mandelin says. “There is a biochemical overabundance of uric acid, which is very irritating and inflammatory.” Gout is part of the crystalline family of arthritis (and the best known, according to Mandelin), which is easy to remember because the disease is caused by deposits of crystallized acid. (Gout’s lesser known cousin is calcium pyrophosphate deposition disease.)
The initial onset of gout has the unique distinction of being tied directly to diet – a characteristic not shared with rheumatoid arthritis, PsA or osteoarthritis. While the disease can occur from joint injury or chemotherapy, most cases arise from diets high in purines (commonly found in shellfish and red meat), excessive alcohol consumption and crash diets, like intermittent fasting.
Symptoms
- Swelling and pain in the joints
- Limited range of motion
- Tenderness and pain in the tendons
Treatment Options
- Steroids
- Prescription medication to block uric acid production and pain relievers
- Non-steroidal anti-inflammatory drugs
- Improvements to diet
Osteoarthritis
Doctor’s notes: “OA is more classically wear and tear, related to aging or overuse,” says Mandelin. While he classifies osteoarthritis as degenerative, he is quick to stress that over time the medical community has come to understand that osteoarthritis is more complicated than simple overuse of the joint. Ongoing research is needed to understand the full picture of what causes degeneration.
Unlike PsA, rheumatoid arthritis and gout, osteoarthritis affects older adults more than any other age group. The majority of people over 60 typically have some form of osteoarthritis, ranging from mild to severe. Common causes of osteoarthritis at a younger age include physical joint injury or overuse of a specific joint. Professional athletes, for instance, are at a high risk for developing osteoarthritis in their 30s and 40s.
Symptoms
- Swelling and pain in the joints
- Limited range of motion
- Tenderness and pain in the tendons
- Morning stiffness
- Bone spurs formed at the affected joint
Treatment Options
- Physical therapy and exercise
- Weight loss for overweight patients
- Non-steroidal anti-inflammatory drugs and pain relievers
- Steroid injection into the affected joint
- Total joint replacement
Illustration by Charles Mertens
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