Osteoarthritis
What it is: More people have this condition than any other form of arthritis. It’s the “wear and tear” that happens when your joints are overused. It usually happens with age, but it can also come from joint injuries or obesity, which puts extra stress on your joints.
Joints that bear weight – such as your knees, hips, feet, and spine – are the most common places it affects. It often comes on gradually over months or years. It makes the affected joint hurt. But you don’t feel sick or have the fatigue that comes with some other types of arthritis.
What happens: You lose your body’s shock absorber. Cartilage, the slippery material that covers the ends of bones, gradually breaks down.
One example is what can happen to your knees when you’re overweight. The extra pounds put more pressure on the cartilage as it gets squeezed between the bones. It gets damaged and wears away, so there isn’t as much left to cushion the joint.
The damaged cartilage makes movement painful. You may hear a grating sound when the roughened cartilage on the surface of the bones rubs together. You may get painful spurs or bumps on the end of the bones, especially on fingers and feet. The joint lining can get inflamed, but it’s not common with osteoarthritis.
Rheumatoid Arthritis
What it is: RA is an autoimmune disease. That means the immune system attacks parts of the body, especially the joints. That leads to inflammation, which can cause severe joint damage if you don’t treat it. About 1 out of every 5 people who have rheumatoid arthritis get lumps on their skin called rheumatoid nodules. These often form over joint areas that receive pressure, such as over knuckles, elbows, or heels.
Psoriatic Arthritis
What it is: People with this condition have inflammation of the skin (psoriasis) and joints (arthritis).
Psoriasis causes patchy, raised, red, and white areas of inflamed skin with scales. It usually affects the tips of the elbows and knees, the scalp, the navel, and skin around the genital areas or anus.
Only about 10% to 30% of people with psoriasis will also get psoriatic arthritis.
What happens: This type of arthritis usually starts between ages 30 and 50, but it can start as early as childhood. It’s equally common among men and women. The skin disease (psoriasis) usually shows up first.
Symptoms: Psoriatic arthritis can swell the fingers and toes. People who have it often have fingernails that are pitted or discolored, too.
In some people, only one joint or a few joints are affected. For example, you could have it in only one knee. Sometimes it affects the spine or just the fingers and toes.