How arthritis develops depends on the type

Arthritis is not a single condition—it is a group of diseases that damage joints in different ways. The most common types, osteoarthritis and rheumatoid arthritis, develop through separate mechanisms. Osteoarthritis happens when the protective cartilage in your joints wears down over time. Rheumatoid arthritis occurs when your immune system mistakenly attacks the lining of your joints. Other types like gout, lupus-related arthritis, and psoriatic arthritis have their own distinct causes. Understanding which type you might develop—or already have—depends on recognizing the factors that trigger each one.

You do not "catch" arthritis the way you catch a cold. Instead, it develops when certain conditions in your body or environment push your joints toward damage. Some people inherit a genetic tendency toward arthritis, while others develop it after an injury, through repetitive stress, or as their body ages. A few types are triggered by infections or autoimmune reactions. The path to arthritis is rarely the same twice.

Key Takeaways

  • Osteoarthritis develops when cartilage in joints wears away over decades, usually from age, weight, or repeated stress on specific joints.
  • Rheumatoid arthritis occurs when your immune system attacks joint linings, and genetics plus an unknown trigger (possibly infection or environmental exposure) play a role.
  • Injury to a joint, even years earlier, can accelerate arthritis in that specific joint.
  • Age, family history, excess weight, and certain occupations increase the risk of developing arthritis, but none of these guarantees you will develop it.

Osteoarthritis: wear and tear on joints

Osteoarthritis is the most common type of arthritis. It develops when the cartilage that cushions the ends of your bones gradually breaks down. This cartilage is slippery tissue that lets bones glide smoothly against each other. As it thins or disappears, bone rubs against bone, causing pain, stiffness, and swelling. This process usually takes years or decades.

Several factors speed up cartilage breakdown. Age is the strongest one—osteoarthritis becomes more common after age 50, though it can start earlier. Excess weight puts extra pressure on weight-bearing joints like your knees, hips, and lower back, accelerating wear. Repetitive stress from certain jobs or sports can damage specific joints; a carpenter's hands or a runner's knees are common examples. A previous injury to a joint—even one that healed years ago—can make that joint more likely to develop arthritis later. Family history matters too; if your parents or grandparents had osteoarthritis, your risk is higher.

Osteoarthritis is not reversible, but it develops slowly enough that many people manage it for years without severe limitation. It typically affects one or a few joints rather than many at once.

Rheumatoid arthritis: an immune system attack

Rheumatoid arthritis is fundamentally different. It occurs when your immune system mistakenly identifies the lining of your joints (called the synovium) as a threat and attacks it. This causes inflammation, swelling, pain, and eventually damage to the cartilage and bone underneath. Unlike osteoarthritis, rheumatoid arthritis can develop quickly and often affects multiple joints at the same time, usually in a symmetrical pattern—both hands, both knees, both feet.

Genetics play a major role. People with a gene called HLA-DR4 or HLA-DRB1 have a higher risk, but carrying the gene does not mean you will develop the disease. Something else has to trigger it. Researchers suspect that trigger might be an infection (like a viral or bacterial infection), environmental exposure, or stress, but the exact cause remains unknown. Sex is also a factor—women are two to three times more likely to develop rheumatoid arthritis than men. It can start at any age but often appears between ages 30 and 60.

Rheumatoid arthritis is an autoimmune disease, meaning your body's defense system is misfiring. This is why it often requires different treatment than osteoarthritis and why early diagnosis matters—medications can slow or stop the immune attack if started soon enough.

Other types of arthritis and their causes

Gout develops when uric acid builds up in your blood and forms crystals in your joints, usually starting in the big toe. It is triggered by diet (foods high in purines like red meat and seafood), dehydration, alcohol consumption, and genetics. Unlike osteoarthritis, gout attacks come suddenly and can be extremely painful, but they are often reversible with treatment.

Psoriatic arthritis occurs in some people who have psoriasis, a skin condition. The same immune system malfunction that causes the skin rash also attacks joints. Lupus-related arthritis develops in people with systemic lupus erythematosus (SLE), another autoimmune disease. Infectious arthritis can follow a bacterial or viral infection that spreads to a joint; Lyme disease, for example, can cause arthritis if untreated. These types are less common than osteoarthritis and rheumatoid arthritis but follow similar patterns: genetics, infection, or immune system dysfunction trigger them.

Risk factors that increase your chances

Certain characteristics make arthritis more likely, though they do not may provide you will develop it. Age is unavoidable—the longer you live, the higher your risk of osteoarthritis. Family history matters for both osteoarthritis and rheumatoid arthritis; if a close relative has arthritis, your risk rises. Body weight directly affects osteoarthritis risk because extra pounds stress your joints. Previous joint injury is a strong predictor; a torn ligament, fracture, or severe sprain in a joint makes that joint vulnerable to arthritis years later.

Occupation and activities matter too. Jobs involving repetitive motions, heavy lifting, or prolonged kneeling (construction, nursing, farming) increase osteoarthritis risk in those specific joints. Athletes who put sustained stress on particular joints face higher risk. Smoking increases the risk of rheumatoid arthritis and may worsen osteoarthritis. Hormones play a role—women are more likely to develop rheumatoid arthritis, and some women notice joint symptoms worsen around menopause.

What happens inside your joint when arthritis develops

To understand how arthritis develops, it helps to know what a healthy joint looks like. Your joints are where two bones meet. The ends of those bones are covered with cartilage, a smooth, slippery material. Surrounding the joint is a capsule lined with synovium, which produces fluid that lubricates the joint. Ligaments and tendons hold everything in place and allow movement.

In osteoarthritis, the cartilage surface cracks and wears away. As it thins, the underlying bone is exposed and can become damaged. The joint produces extra fluid, causing swelling. Bone spurs (small growths) may form around the joint edges. The result is pain, stiffness, and reduced movement.

In rheumatoid arthritis, the synovium becomes inflamed and thickened. This inflammation spreads to the cartilage and bone, eating away at them. The joint swells, becomes warm and tender, and loses its shape. Over time, the bones can shift out of alignment. This is why early treatment is critical—stopping the inflammation early can prevent permanent joint damage.

Frequently Asked Questions

Can you develop arthritis from cracking your knuckles?

No. Decades of research show no link between knuckle cracking and arthritis. The sound comes from bubbles forming and popping in the fluid around your joints, not from damage. People who crack their knuckles regularly do not have higher arthritis rates than those who do not.

Is arthritis hereditary?

Genetics increase your risk, especially for rheumatoid arthritis and osteoarthritis, but inheriting a family history does not mean you will definitely develop arthritis. Environmental factors, lifestyle, and chance all play a role. Many people with a family history never develop arthritis, and many without family history do.

Can you get arthritis from being cold or wet?

No scientific evidence supports this. Cold weather may temporarily worsen pain in people who already have arthritis because cold can make joints stiffer, but it does not cause arthritis to develop. The myth likely persists because people notice their arthritis symptoms flare in winter.

What is the difference between arthritis and arthralgia?

Arthralgia means joint pain without actual joint damage. Arthritis means the joint itself is inflamed or damaged. You can have arthralgia from many causes—overuse, strain, or viral infection—without having arthritis. Arthritis is a diagnosis that requires imaging or blood tests to confirm.

Can you prevent arthritis if it runs in your family?

You cannot eliminate genetic risk, but you can reduce modifiable factors. Maintaining a healthy weight, staying active, protecting your joints from injury, avoiding smoking, and managing stress may lower your risk or delay onset. These steps help even if arthritis eventually develops, because they can slow its progression.