What are the Different Types of Arthritis?

What comes to mind when you hear the word “arthritis”? An older adult with joint pain and stiffness, perhaps. Maybe physical therapy, walking aids, or hip or knee replacement surgery. This makes sense, considering over 32 million adults in the U.S. have the most common form of arthritis, known as osteoarthritis (OA), and nearly 50% of adults with OA are over the age of 65. 

But did you know that there are dozens of other types of arthritis? Many of these conditions cause symptoms beyond joint pain, stiffness, and swelling. Some even affect children and young adults. These conditions are less common than OA, but they are complex diseases that significantly impact those who live with them.

“Many of my patients come to me knowing that they have arthritis, but they don’t always know which type of arthritis they have, that there are different types, or that it’s possible to have multiple types,” explains Rui Zhang, MD, Ph.D., a rheumatologist at Nashua Rheumatology. “It is important for patients to understand their exact diagnosis so they can be active participants in their health care.”

Below, Dr. Zhang provides an overview of three common types of arthritis – osteoarthritis, rheumatoid arthritis, and psoriatic arthritis – how they differ, and how people with arthritis can find relief. 

What is Osteoarthritis?
Osteoarthritis (OA) – the most common type of arthritis – occurs when the rubbery material (cartilage) between two bones wears down. When this happens, the joint bones begin to rub against each other, causing pain, stiffness, and swelling. OA usually starts after age 45, and it is most common in people over age 65. Factors that increase one’s risk of developing OA include being overweight, a history of joint injury, certain competitive sports, occupations that require repeated movements, and some genetic factors.

OA most commonly affects the knees, hips, lower back, neck, small joints of the fingers, and the base of the thumb and big toe. Unlike inflammatory arthritis, such as rheumatoid arthritis and psoriatic arthritis, OA is not an autoimmune disease. It does not cause symptoms like fatigue, fever, or skin and eye problems.

Both rheumatologists and orthopedic surgeons can treat osteoarthritis.

What is Rheumatoid Arthritis?
Rheumatoid arthritis (RA) is a disease that causes joint pain, swelling, and stiffness. It is an autoimmune disease in which a person’s immune system mistakenly attacks the healthy joints and other parts of the body. RA affects around 1% of the population and can occur at any age.

The specific cause of RA is not yet fully understood, but there is strong scientific evidence that environmental and genetic factors play a role. Smoking, infections, or certain hormones are possible triggers for the autoimmune response. Certain genes affect the likelihood of developing RA, so people who have a relative with the disease are at increased risk of having it themselves.

Whereas OA tends to affect big joints like the knees and hips, RA usually starts in the small joints of the fingers, the balls of the feet, and the wrists. It often affects both sides of the body at the same time. RA can also cause various other symptoms, such as skin problems, eye problems, fatigue, lung problems, muscle pain, skin nodules, weakness, weight loss, and more.

Rheumatologists treat rheumatoid arthritis. 

What is Psoriatic Arthritis?
Psoriatic arthritis is an autoimmune disease that affects some people with psoriasis, a chronic skin condition. The primary symptoms are joint pain, swelling, and stiffness; difficulty moving, especially first thing in the morning; skin patches (plaques); and nail abnormalities, such as pitting, nail crumbling, and discoloration. About 30% of people with psoriasis will develop psoriatic arthritis, and psoriasis precedes arthritis by an average of 8 to 10 years in ~70% of patients. The condition affects between 0.1-0.2% of the global population and affects men and women equally.

Psoriatic arthritis usually affects certain groups of joints, such as the ends of the fingers and toes; back of the heel or the sole; multiple joints on one or both sides of the body; or the joints of the spine, particularly the lower back and above the tail bone.

People with psoriatic arthritis are often treated by a rheumatologist and dermatologist who collaborate to ensure all aspects of the disease are being treated effectively.

Arthritis Care
There are no cures for rheumatoid arthritis, psoriatic arthritis, or osteoarthritis. However, treatment options for each condition help control symptoms, prevent further joint damage, and improve quality of life.
Medications that might treat all three types of arthritis include nonsteroidal anti-inflammatory drugs (NSAIDs), oral steroids or steroid injections, and pain medication.

As autoimmune diseases, both rheumatoid and psoriatic arthritis are often treated using disease-modifying antirheumatic drugs (DMARDs). DMARDs are special medications that alter or stop part of the inflammatory process.

“There are conventional DMARDs, like methotrexate, and biologic DMARDs, like Humira and Remicade,” says Dr. Zhang. “Conventional DMARDs target the entire immune system, while biologics target a specific step in the inflammatory process. Instead of treating symptoms, these medications decrease the immune system activity that causes joint damage.”

People with osteoarthritis, psoriatic arthritis, and rheumatoid arthritis may also find that some lifestyle modifications help their symptoms. For example, people with all three types of arthritis need to stay active – either on their own or under the supervision of a physical therapist – to prevent muscle weakness and ease stiffness.

Arthritis of any kind can only be diagnosed by a qualified health care provider. If you think you might have arthritis, talk to your primary care provider about your concerns. They can order specific laboratory and imaging tests to determine which specialist to refer you to. If you end up receiving an arthritis diagnosis – whether it’s osteoarthritis or autoimmune arthritis – you can rest assured that Dr. Zhang and her colleagues at Nashua Rheumatology are there to help you find relief.

Posted: 3/30/2022