How arthritis develops in your joints

Arthritis is not something you catch or inherit in a single moment. It develops over time when the protective tissue in your joints — called cartilage — breaks down, or when your immune system attacks the joint lining. The two most common types, osteoarthritis and rheumatoid arthritis, develop through different paths, but both result in pain, stiffness, and swelling that worsens gradually.

Most people develop arthritis because of a combination of things: how their joints are built, how much wear and tear they experience, their age, and sometimes their genes. A few people are born with joint shapes that make arthritis more likely. Others develop it after an injury. Many develop it straightforward because their joints have been used for decades. There is no single moment when you "get" arthritis — it is a process that unfolds over months or years.

Key Takeaways

  • Osteoarthritis develops when cartilage wears away from repeated use, injury, or age, and is the most common type in people over 65.
  • Rheumatoid arthritis occurs when your immune system mistakenly attacks joint linings, can start at any age, and often runs in families.
  • Risk factors include previous joint injuries, being overweight, repetitive joint stress, and having a family history of arthritis.
  • Symptoms usually appear gradually — stiffness in the morning, pain after activity, or swelling that comes and goes — before becoming constant.
  • A doctor can diagnose arthritis through a physical exam, imaging tests like X-rays, and blood tests that look for specific markers.

Osteoarthritis: wear and tear on your joints

Osteoarthritis is the most common type, especially as people age. It happens when the cartilage that cushions the ends of your bones gradually wears away. Cartilage is smooth and slippery — it lets your bones glide past each other without friction. When it thins or cracks, the bones underneath start to rub together, causing pain and stiffness.

This wear and tear can happen for several reasons. Years of normal use — walking, bending, gripping — gradually breaks down cartilage. Extra weight puts more pressure on weight-bearing joints like your knees, hips, and lower back, speeding up the process. A previous injury, even one that healed years ago, can damage cartilage and make that joint more likely to develop osteoarthritis later. Some people's joints are straightforward built in a way that puts uneven stress on the cartilage, wearing it faster than average.

Osteoarthritis usually starts in one or two joints and can spread to others over time. It is most common in the hands, knees, hips, lower back, and neck — the joints that bear weight or move frequently. Most people do not notice symptoms until their 50s or 60s, though the cartilage damage may have been happening for years before that.

Rheumatoid arthritis: when your immune system attacks joints

Rheumatoid arthritis is different from osteoarthritis. Instead of cartilage wearing away from use, your immune system mistakenly attacks the lining of your joints, called the synovium. This lining becomes inflamed, swollen, and painful. Over time, this inflammation can damage the cartilage and bone underneath.

Rheumatoid arthritis often runs in families, suggesting genetics play a role. If your parent or sibling has it, your risk is higher. It can start at any age, though it is most common between ages 40 and 60. Women are more likely to develop it than men. Unlike osteoarthritis, which usually affects one side of your body, rheumatoid arthritis typically affects the same joints on both sides — both hands, both knees, both feet.

The cause is not fully understood, but researchers believe a combination of genes and something in the environment — possibly a virus or infection — triggers the immune system to attack. Once it starts, the inflammation can spread to other joints and even affect organs like the heart and lungs if left untreated. This is why early diagnosis and treatment matter more with rheumatoid arthritis than with osteoarthritis.

Risk factors that make arthritis more likely

Age is the strongest risk factor for osteoarthritis. The longer your joints have been in use, the more wear and tear they accumulate. Most people over 65 have some cartilage damage visible on X-rays, though not all have symptoms.

Previous injuries to a joint significantly increase the risk that joint will develop arthritis. A torn ligament, broken bone, or severe sprain can damage cartilage or change how the joint moves, putting stress on the remaining cartilage. This can happen years or even decades after the original injury.

Weight affects your risk, especially for osteoarthritis in the knees, hips, and lower back. Extra weight increases the load these joints carry with every step. Losing even 10 pounds can reduce stress on knee joints and slow cartilage breakdown.

Repetitive stress from work or hobbies can wear down cartilage faster. Jobs that require heavy lifting, kneeling, or gripping, or sports played at a high level for many years, can accelerate joint damage. This is separate from normal activity — it is the cumulative effect of the same motion thousands of times.

Family history matters more for rheumatoid arthritis than osteoarthritis, though both can run in families. If a close relative has rheumatoid arthritis, your risk is higher. For osteoarthritis, having a parent with it increases your risk somewhat, but it is not as strong a predictor.

How symptoms appear and progress

Arthritis symptoms usually develop slowly. Many people notice stiffness first — joints that feel tight or hard to move, especially in the morning or after sitting still for a while. This stiffness often improves within 30 minutes of moving around. Pain may come and go at first, appearing after activity or at the end of the day, then disappearing after rest.

As cartilage continues to break down, symptoms become more constant. Pain may be present even at rest. Swelling appears — the joint looks puffy or feels warm to the touch. The range of motion decreases — you cannot bend or straighten the joint as far as before. Some people develop a grinding or creaking sensation in the joint.

With rheumatoid arthritis, symptoms often come on more suddenly than with osteoarthritis. You might wake up with swollen, painful joints that feel warm. Fatigue and a low fever sometimes accompany the joint symptoms. These flare-ups can last days or weeks, then improve, then return.

The speed of progression varies widely. Some people have mild symptoms that stay the same for years. Others experience rapid worsening. How quickly your arthritis progresses depends on the type, which joints are affected, how well you manage it, and individual factors doctors do not yet fully understand.

When to see a doctor about joint pain

See a doctor if joint pain or stiffness lasts more than two weeks, even if it comes and goes. Do not wait for it to become severe. Early diagnosis — especially for rheumatoid arthritis — allows treatment to start before significant damage occurs.

Tell your doctor exactly which joints hurt, when the pain started, what makes it better or worse, and whether you have swelling or stiffness. Mention any injuries to that joint in the past, your family history of arthritis, and your job or hobbies that might stress the joint. Bring a list of all medications and supplements you take.

Your doctor will examine the joint, ask about your symptoms, and may order imaging tests like X-rays or ultrasound. Blood tests can detect markers of rheumatoid arthritis, such as rheumatoid factor or anti-CCP antibodies. These tests help your doctor determine which type of arthritis you have and how to treat it.

Frequently Asked Questions

Can you get arthritis from cracking your knuckles?

No. Studies have found no link between cracking knuckles and arthritis development. Cracking is the sound of gas bubbles forming and popping in the fluid around your joints — it does not damage cartilage or cause arthritis later.

Is arthritis hereditary?

Rheumatoid arthritis runs in families more strongly than osteoarthritis does. If a parent or sibling has rheumatoid arthritis, your risk is higher. For osteoarthritis, family history increases risk somewhat, but age, weight, and joint use matter more.

Can you develop arthritis at a young age?

Yes. Rheumatoid arthritis can start in childhood or early adulthood. Osteoarthritis is rare in young people but can develop after a serious joint injury. Young athletes who injure joints are at higher risk for early osteoarthritis in that joint.

Does arthritis always get worse over time?

Not necessarily. Osteoarthritis progresses at different rates — some people have stable symptoms for years. Rheumatoid arthritis can be slowed or even put into remission with early treatment. How your arthritis progresses depends on the type, which joints are affected, and how well it is managed.

What is the difference between arthritis and normal joint pain?

Normal joint pain from overuse usually improves within days of rest. Arthritis pain is persistent — it lasts weeks or months, often worsens with activity, and may be accompanied by swelling, stiffness, or warmth in the joint. If pain does not improve with rest after two weeks, see a doctor.