The cause or causes of arthritis are oftentimes difficult to determine because there are many factors that contribute to the development of this common disease.

Arthritis involves the breakdown of cartilage. Cartilage normally protects the joint, allowing for smooth movement. Cartilage also absorbs shock when pressure is placed on the joint, like when you walk. Without the usual amount of cartilage, the bones rub together, causing pain, swelling (inflammation), and stiffness.

You may have joint inflammation for a variety of reasons, including:

* Broken bone

* Infection (usually caused by bacteria or viruses)

* An autoimmune disease (the body attacks itself because the immune system believes a body part is foreign)

* General "wear and tear" on joints

Often, the inflammation goes away after the injury has healed, the disease is treated, or the infection has been cleared.

With some injuries and diseases, the inflammation does not go away or destruction results in long-term pain and deformity.

When this happens, you have chronic arthritis. Osteoarthritis is the most common type and is more likely to occur as you age.

You may feel it in any of your joints, but most commonly in your hips, knees or fingers. Risk factors for osteoarthritis include:

* Being overweight

* Previously injuring the affected joint

* Using the affected joint in a repetitive action that puts stress on the joint (baseball players, ballet dancers, and construction workers are all at risk)

Arthritis can occur in men and women of all ages. About 37 million people in America have arthritis of some kind, which is almost 1 out of every 7 people.

Other types or cause of arthritis include:

* Rheumatoid arthritis (in adults)

* Juvenile rheumatoid arthritis (in children)

* Systemic lupus erythematosus (SLE)

* Gout

* Scleroderma

* Psoriatic arthritis

* Ankylosing spondylitis

* Reiter's syndrome (reactive arthritis)

* Adult Still's disease

* Viral arthritis

* Gonococcal arthritis

* Other bacterial infections (non-gonococcal bacterial arthritis )

* Tertiary Lyme disease (the late stage)

* Tuberculous arthritis

* Fungal infections such as blastomycosis

Rheumatoid Arthritis Symptom

If you have arthritis, you may experience:

* Joint pain

* Joint swelling

* Stiffness, especially in the morning

* Warmth around a joint

* Redness of the skin around a joint

* Reduced ability to move the joint

Self-destructive immune response of rheumatoid arthritis may be caused by a combination of genetic susceptibility and an environmental trigger. Changing hormones may also play an important role in disease, possibly in response to an infection of the environment.

More than one gene has been linked to the risk of rheumatoid arthritis. Specific genes may increase the likelihood of a person developing the disease, and could also partly determine how serious his condition is. However, because not all people with a genetic predisposition to rheumatoid arthritis actually have the disease, other factors should be important.

A specific environmental trigger has not been found, but some research suggests that infection by a virus or bacterium leads to rheumatoid arthritis in people genetically susceptible. That does not mean that rheumatoid arthritis is contagious. People with rheumatoid arthritis appear to have more antibodies in the synovial fluid in their joints, suggesting that there may be an infection. Low levels of hormones of the adrenal gland are common in people with rheumatoid arthritis, but how hormones interact with genetic and environmental factors is unknown. Changes hormone can contribute to the progression of rheumatoid arthritis.

Rheumatoid arthritis may occur independently of other conditions, but its causes and its relationship with other diseases are not well understood. A different way of chronic arthritis can sometimes develop in rheumatoid arthritis. It is also possible that infections or other environmental triggers exist that may cause rheumatoid arthritis in people who already have a gene for the disease.