Emergency Health Information
Septic Arthritis (Joint Infection)
Septic arthritis is an infection inside a joint. It needs urgent medical assessment because delay can damage the joint and may lead to serious illness.
Urgent Action Needed
Do not wait for a routine clinic appointment
If a joint becomes suddenly very painful, swollen, red or hot — especially with fever, chills or feeling generally unwell — attend an emergency department as soon as possible. Call 999 for emergency help if the person is severely unwell, confused, has breathing difficulty, faints or cannot be safely transported.
Common Warning Signs
These symptoms can develop quickly over a few days. Not everyone will have a fever.
- Sudden severe pain, usually affecting one joint
- Rapid swelling, warmth, redness or marked tenderness around a joint
- Difficulty moving the joint or bearing weight
- Fever, chills, feeling hot or cold, or generally unwell
- In children: new limp, refusal to use a limb, marked distress on movement or fever
What Is Septic Arthritis?
- Germs can reach a joint through the bloodstream from an infection elsewhere in the body.
- Infection can also occur after an injury that breaks the skin, a joint procedure or surgery.
- A hot, swollen joint has more than one possible cause. Gout, inflammatory arthritis and injury can look similar, so a medical assessment is needed.
Who needs extra caution?
- People with diabetes, reduced immunity or inflammatory joint disease
- People with a recent skin infection, wound, injection, joint surgery or artificial joint
- Older adults, young children and people who are currently unwell
How Is It Assessed?
Symptoms or a single blood test cannot by themselves confirm or exclude infection. Doctors will assess the situation urgently.
- Urgent clinical assessment and examination
- Blood tests and, where appropriate, blood cultures
- Sampling joint fluid with a needle to look for infection and identify a germ
- X-ray, ultrasound, CT or MRI only when clinically appropriate
General Treatment Approach
- Treatment is usually provided in hospital when septic arthritis is suspected or confirmed.
- Antibiotics may be given directly into a vein, followed by further treatment based on clinical findings and test results.
- The joint may need drainage. Some people need an operation, depending on the joint, infection and response to treatment.
Frequently Asked Questions
Is septic arthritis the same as gout?
No. Gout and other inflammatory conditions can also cause a painful, swollen joint. Because the symptoms can overlap, a hot and swollen joint — especially with fever or feeling unwell — needs urgent medical assessment to exclude infection.
Can I wait and see if the pain settles?
Do not wait for a routine appointment if severe joint pain starts suddenly, the joint is hot, red or swollen, or there is fever or significant illness. Attend an emergency department promptly.
Can it happen after joint surgery or joint replacement?
Joint infection can occur after a procedure or surgery. New or worsening joint pain, swelling, wound discharge, fever or feeling unwell after surgery should be assessed urgently.