Why "arthritis" is more than one disease

Oct 13

A lot of people use the word "arthritis" as if it means one thing. It doesn't. According to the CDC, arthritis includes more than 100 conditions that affect the joints. Some come from wear and tear. Others are inflammatory, meaning the pain and swelling come from something happening inside the body, like crystals forming in a joint or the immune system attacking healthy tissue.

That difference matters. Two people can both say "my joints hurt" and have very different conditions. This guide covers some common types of inflammatory joint pain and when it's time to get checked.

Gout: uric acid, sudden flares, and the big toe

Gout happens when there's too much uric acid, a normal waste product, in the body. When levels get too high, sharp crystals can form in a joint and cause severe pain and swelling.

Gout usually affects one joint at a time, and the big toe is the classic spot. It can also show up in the foot, ankle or knee. The joint may be painful, swollen, red and warm.

The hallmark of gout is the flare. Symptoms often come on suddenly, many times at night, and can last for days or weeks. Then there may be stretches with no symptoms before the next flare. Over time, if gout isn't managed, flares may happen more often and last longer, and lumps called tophi can form around the joints.

Anyone can get gout, but it's more common in men, people with a family history of gout, and people with conditions like high blood pressure, diabetes, heart failure or poor kidney function. Obesity, certain medicines, and foods and drinks high in purines (like alcohol, sugary drinks, red meat and shellfish) can also raise uric acid levels.

Rheumatoid arthritis: an immune condition

Rheumatoid arthritis (RA) is an autoimmune disease. In RA, the immune system attacks the body's own tissues, mainly the lining of the joints. This causes pain, swelling, stiffness and, over time, joint damage.

A few things tend to set RA apart:

Both sides of the body. RA often follows a symmetrical pattern. If your right hand is affected, your left hand may be too.
Smaller joints. It's most common in the wrists, hands and feet, though it can affect many other joints.
Morning stiffness. Stiffness that lasts longer than 30 minutes after waking up, or after resting for a long time, is a common sign.
Whole-body symptoms. RA can bring fatigue, an occasional low-grade fever and loss of appetite.

Women are about two to three times more likely than men to have RA, and the risk goes up with age. Smoking and family history also play a role. RA can also involve the heart, lungs, eyes and skin, which is one reason early diagnosis matters.

The ones people often miss

Two other inflammatory conditions are easy to brush off as "just a bad back" or "just getting older."

Axial spondyloarthritis: back pain that gets better when you move

Axial spondyloarthritis (axSpA) is a type of inflammatory arthritis that mainly affects the spine and pelvis. It often causes long-term back pain in young adults, with symptoms usually starting somewhere between the late teens and age 45.

What makes this back pain different is how it reacts to activity. Back pain from a strain or injury usually feels better with rest. With axSpA, the pain tends to come on gradually, hurt less when you're moving, and feel worse after rest. If you've had back pain for months that loosens up as you move, with no injury behind it, mention it to your doctor.

Polymyalgia rheumatica: shoulder and hip stiffness after 50

Polymyalgia rheumatica (PMR) is an inflammatory condition that causes muscle pain and stiffness, mostly in the shoulders, neck and hips. It mainly affects people over 50 and rarely affects younger people. The stiffness is usually worst in the morning and often starts in both shoulders before spreading to the hips.

PMR is linked to a related condition called giant cell arteritis, which causes inflammation in blood vessels. Its warning signs can include headaches, vision problems, jaw pain and a tender scalp. If you notice any of these, contact a doctor promptly.

Gout vs. rheumatoid arthritis at a glance

Here's a simple side-by-side look at gout vs rheumatoid arthritis. Real symptoms don't always follow the textbook, so use this as a starting point for a talk with your doctor, not a self-diagnosis tool.

	Gout	Rheumatoid arthritis
What's behind it	Uric acid crystals forming in a joint	The immune system attacking the joint lining
Joints affected	Usually one joint at a time, often the big toe	Several joints, often on both sides of the body
How it feels	Sudden, severe flares that can last days or weeks, with breaks in between	Ongoing pain, swelling and stiffness, with flares and calmer periods
Morning stiffness	Not a typical feature	Common, often lasting more than 30 minutes
Who it affects more	Men	Women (about two to three times more often)
Common tests	Joint fluid test for crystals, uric acid blood test, imaging	Blood tests for inflammation and RA-related antibodies, imaging

When to see a rheumatologist, and what tests to expect

A rheumatologist is a doctor who specializes in arthritis. Many people start with their regular doctor, who can refer them. The CDC notes that it's best to get RA diagnosed as soon as possible, because early care helps keep symptoms from getting worse and damaging the joints.

It's a good idea to talk with your doctor if you have:

A joint that suddenly becomes very painful, swollen, red or warm
Joint pain or swelling that keeps coming back
Stiffness that lasts more than 30 minutes most mornings
Pain in the same joints on both sides of your body
Back pain that has lasted months and feels better when you move
New stiffness in your shoulders or hips after age 50

Your visit will usually start with a physical exam and questions about your health history. Testing depends on what your doctor suspects and may include:

Joint fluid test. If gout is possible, a doctor may use a needle to take a small amount of fluid from the joint and check it for uric acid crystals under a microscope.
Blood tests. These can check uric acid levels, signs of inflammation (called ESR and CRP), and antibodies linked to RA, such as rheumatoid factor and anti-CCP. A high uric acid level alone doesn't confirm gout. Not everyone with high levels gets gout, and some people have normal levels during a flare.
Imaging. X-rays, ultrasound or MRI can help rule out other causes and show changes in the joints.

RA in particular can be hard to diagnose early, because its first symptoms can look like other common conditions. No article, including this one, can tell you exactly what's going on in your joints. A doctor can.

Research in Houston

Prolato Clinical Research Center in Houston runs research studies in gout, rheumatoid arthritis and other rheumatology conditions. Taking part is always voluntary, and each study has its own requirements. If you'd like to see what's currently enrolling, learn more about our patient studies.

Sources

Muznah Fawad