How common forms of arthritis differ, how they are evaluated, and when to seek care
Arthritis is not one disease. It is a broad name for conditions that can cause joint pain, stiffness, swelling, inflammation, or loss of movement. Some forms mainly involve changes within the joint over time. Others are caused by the immune system, crystals, infection, or injury. Knowing the type matters because treatments that help one condition may not treat another.
This page provides general education, not a diagnosis or individual medical advice.
Osteoarthritis (pronounced os-tee-oh-arth-RY-tis, sometimes shortened to "OA") is a joint condition caused by the gradual breakdown of cartilage, the tissue that cushions the ends of bones. As cartilage wears down, the joint can become painful, stiff, and less flexible, especially with movement or after periods of rest. It's the most common form of arthritis, and it's different from rheumatoid or psoriatic arthritis, which are driven by the immune system rather than everyday wear on the joint.
Outside the US, and in some older or translated medical literature, this same condition is often called arthrosis (or osteoarthrosis). It's not a different disease, just a different regional name for osteoarthritis.
Osteoarthritis is the most common form of arthritis. It affects the whole joint, including cartilage, bone, the joint lining, ligaments, and nearby muscles. It becomes more common with age, but it is not simply an unavoidable part of getting older.
Pain often worsens with activity or prolonged use. Stiffness after rest may ease once the joint starts moving.
Usual care: exercise, physical therapy, medicines, braces or aids, selected procedures, and sometimes surgery.
Rheumatoid arthritis occurs when the immune system attacks tissues around the joints. It often affects several joints and may involve both sides of the body.
Early treatment matters because uncontrolled inflammation can permanently damage joints and affect other organs.
Usual care: a rheumatologist and disease-modifying medicines, with therapy and ongoing monitoring.
Psoriatic arthritis is linked with psoriasis. It can affect joints, the spine, fingers and toes, tendons, skin, and nails. Joint symptoms can sometimes begin before obvious psoriasis appears.
Usual care: rheumatology care, immune-modifying treatment, exercise, and treatment of associated skin disease.
Gout is caused by uric acid crystals forming in and around a joint. A flare often starts suddenly with severe pain, redness, warmth, and swelling.
Usual care: medicine for the acute flare and, when needed, long-term treatment to lower uric acid.
Uric acid is not the only crystal that can cause arthritis. Calcium pyrophosphate deposition disease, sometimes called pseudogout, can also cause sudden pain and swelling and may resemble gout or infection.
This condition mainly affects the spine and the joints connecting the spine to the pelvis. Pain may be worse after rest, improve with movement, and come with prolonged morning stiffness.
Usual care: rheumatology evaluation, exercise, physical therapy, and anti-inflammatory or immune-targeted medicines when appropriate.
An infection inside a joint can cause rapid pain, warmth, swelling, fever, or an inability to use the joint. It can resemble gout or another inflammatory flare.
Usual care: urgent joint-fluid testing, drainage, and antimicrobial treatment when infection is confirmed.
There is no single test that identifies every form of arthritis. Diagnosis usually comes from several pieces of information considered together.
Often evaluates new symptoms, orders initial tests, treats common problems, and coordinates referrals.
Specializes in autoimmune, inflammatory, and crystal arthritis, including rheumatoid arthritis, psoriatic arthritis, gout, and axial spondyloarthritis.
Evaluates injuries, structural joint damage, advanced osteoarthritis, and whether surgery may be appropriate.
Helps with strength, mobility, balance, joint protection, assistive devices, and adapting daily activities.
May help when persistent pain has several causes or remains difficult to manage.
Evaluates whether LDRT may be a reasonable option for selected patients with osteoarthritis or degenerative musculoskeletal pain.
Long periods of inactivity can add to stiffness and weakness. Walking, cycling, swimming, water exercise, tai chi, and gradual strengthening are joint-friendly options for many people.
Stronger muscles can help support a painful joint. Start slowly and ask a clinician or physical therapist for guidance when pain, balance, or other health conditions limit activity.
Break demanding tasks into smaller steps, alternate heavier and lighter activities, and take short rests before pain becomes overwhelming.
Supportive footwear, a correctly fitted cane, braces, splints, raised seats, and simple household tools can make daily activities easier.
Heat may ease stiffness and relax muscles. Cold may help short-term pain or swelling after activity. Protect the skin and avoid extreme temperatures.
Pain can disrupt sleep, and poor sleep can make pain harder to manage. Ongoing pain can also affect mood, concentration, work, and relationships. These concerns belong in the treatment conversation.
Sources: NIAMS arthritis overview, NIAMS osteoarthritis guidance, NIAMS rheumatoid arthritis guidance, and CDC arthritis basics.