How common is a hot, red, swollen joint in septic arthritis?

Septic arthritis occurs when an infection affects the space inside a joint. Inflammation can cause marked swelling, warmth, redness, and pain, often with difficulty moving the joint. The illness may develop quickly and can affect a knee, hip, shoulder, wrist, or another joint.

This appearance does not identify the cause by itself. Gout, an inflammatory arthritis flare, or an injury may also cause a hot and swollen joint. Doctors may examine you urgently and test blood or fluid taken from the joint to distinguish infection from other problems.

Treat a new hot, red, swollen joint as a reason for same-day medical assessment, particularly if pain is severe or movement is restricted. Tell the clinician about fever, recent surgery or injections, wounds, immune-system conditions, and medicines. Do not massage the joint or delay care while waiting to see whether it settles.

Go to an emergency service if the joint changes suddenly and you also have fever, shaking chills, confusion, faintness, or feel seriously unwell. Urgent attention is also needed when you cannot move the joint or put weight through the limb. Prompt treatment helps limit harm to the joint and wider health.

Ask whether the joint needs aspiration, which tests will check for infection, and what symptoms should prompt immediate return after treatment begins.