What is arthritis?

"Arthritis" literally means joint inflammation. Although joint inflammation is a symptom or sign rather than a specific diagnosis, the term arthritis is often used to refer to any disorder that affects the joints. Joints are places where two bones meet, such as your elbow or knee.

There are different types of arthritis. In some diseases in which arthritis occurs, other organs, such as your eyes, heart, or skin, can also be affected.

Fortunately, current treatments allow most people with arthritis to lead active and productive lives.

Representation of a normal and other joint affected by arthritis

What are the types of arthritis?

There are several types of arthritis. Common ones include:

  • Ankylosing Spondylitis is arthritis that affects the spine. It often involves redness, heat, swelling, and pain in the spine or in the joint where the bottom of the spine joins the pelvic bone.
  • Gout is caused by crystals that build up in the joints. It usually affects the big toe, but many other joints may be affected.
  • Juvenile Arthritis is the term used to describe arthritis in children. Arthritis is caused by inflammation of the joints.
  • Osteoarthritis usually comes with age and most often affects the fingers, knees, and hips. Sometimes osteoarthritis follows a joint injury. For example, you might have badly injured your knee when young and develop arthritis in your knee joint years later.
  • Psoriatic Arthritis can occur in people who have psoriasis (scaly red and white skin patches). It affects the skin, joints, and areas where tissues attach to bone. 
  • Reactive Arthritis is pain or swelling in a joint that is caused by an infection in your body. You may also have red, swollen eyes and a swollen urinary tract.
  • Rheumatoid arthritis happens when the body’s own defense system doesn’t work properly. It affects joints and bones (often of the hands and feet), and may also affect internal organs and systems. You may feel sick or tired, and you may have a fever.

Arthritis is seen with other conditions. These include:

  • Lupus happens when the body’s defense system harms the joints, heart, skin, kidneys, and other organs.
  • Infection that gets into a joint and destroys the cushion between the bones.

What are the symptoms of arthritis?

Symptoms of arthritis can include:

  • Pain, redness, heat, and swelling in your joints. 
  • Trouble moving around.
  • Fever.
  • Weight loss.
  • Breathing problems.
  • Rash or itch.

These symptoms may also be signs of other illnesses.

What causes arthritis?

There are probably many genes that make people more likely to have arthritis. Research has found some of these genes.

If you have the gene linked with arthritis, something in your environment—such as a virus or injury—may trigger the condition.