Does septic arthritis cause joint swelling?

A joint affected by septic arthritis may look enlarged, feel tight, and become painful when moved. Fluid can collect inside the joint, while surrounding tissues may also become inflamed. The swelling may develop over a short time and can be accompanied by warmth, redness, restricted movement, or fever. A hip infection may show less visible swelling because the joint lies deep inside the body.

Most people with septic arthritis notice joint swelling when the infection affects a readily visible joint, but swelling has many possible causes. Injury, gout, and other inflammatory problems can produce similar changes. The symptom alone cannot determine the diagnosis.

Contact an urgent medical service for new swelling with significant pain, warmth, redness, or reduced movement. Keep the joint comfortable and avoid heavy use while waiting. Do not puncture or squeeze the swelling. A clinician may need to examine the joint and consider blood tests, imaging, or sampling the joint fluid.

Seek emergency care if swelling is rapidly increasing, you cannot use the limb, you have fever or chills, severe pain, confusion, faintness, or a wound near the joint. People with diabetes, recent joint surgery, or reduced immunity should seek advice promptly because infection may progress without dramatic early symptoms.

Ask whether the swelling is inside the joint, whether fluid testing is needed, which causes are being considered, and what movement is safe until the evaluation is complete. Explain when the swelling started and whether heat, redness, fever, or an injury came first.