Septic Arthritis: Causes, Symptoms, and Treatment
Medically reviewed by Sumiran Racherla, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats Septic Arthritis?
An infectious disease doctor (a doctor who treats infections) or an orthopedic surgeon (a bone and joint surgeon) often cares for people with septic arthritis. A rheumatologist (a doctor who treats joint diseases) may also help. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What is septic arthritis?
Septic arthritis is swelling and irritation of a joint that is caused by a bacterial or fungal infection. Doctors also call it bacterial arthritis. Viruses can also cause infectious arthritis.
Septic arthritis caused by the bacteria that cause gonorrhea has different symptoms and is called gonococcal arthritis. The knee and hip are commonly affected.
Symptoms
Symptoms usually come on quickly.
- A fever and swelling, usually in just one joint.
- Intense joint pain that gets worse with movement.
- Redness of the joint.
- Not being able to move the arm or leg that has the infected joint.
Chills may occur, but they are uncommon.
Babies may cry when the infected joint is moved, such as during diaper changes.
Pain, swelling, redness, and stiffness can build up within a few hours or days. In a few people, the infection grows slowly over months or even years.
In people who already have rheumatoid arthritis (a long-lasting joint disease), the infection may seem like a flare-up of that condition.
Causes and who gets it
Septic arthritis starts when germs spread through the blood to a joint. A germ can also enter the joint directly during an injury or during surgery.
Most sudden cases are caused by Staphylococcus or Streptococcus bacteria. Slow, long-lasting cases are less common and are caused by germs such as tuberculosis bacteria and the yeast Candida albicans.
These things raise the risk:
- An artificial joint implant.
- A bacterial infection somewhere else in the body.
- Bacteria in the blood.
- A long-term illness such as diabetes, rheumatoid arthritis, or sickle cell disease.
- Using drugs or medicine by injection into a vein.
- Medicines that weaken the immune system.
- A recent joint injury.
- Recent joint surgery, including arthroscopy (surgery done with a small camera in the joint).
Septic arthritis may be seen at any age. In children, it occurs most often in those younger than 3 years. The hip is often the site of infection in infants. Group B Streptococcus bacteria cause most of these cases. Haemophilus influenzae is another common cause, especially if the child has not been vaccinated against it.
How doctors diagnose it
A health care provider will examine the joint and ask about your symptoms. Doctors may use a needle to take a sample of joint fluid and test it, including a culture (a test that grows germs). Testing the joint fluid helps doctors find the germ that is causing the infection.
A blood culture checks the blood for germs. An X-ray of the joint may be done. Blood work, such as a complete blood count, may also be done.
Treatment
Antibiotics (medicines that kill germs) are used to treat the infection. Early treatment is needed to stop the infection from spreading and to avoid joint damage. The choice of antibiotic depends on the germ involved. Treatment usually continues for at least two weeks after all signs of swelling and irritation are gone.
If fluid builds up quickly in the joint, a needle may be used to draw it out. Severe cases may need surgery to drain and wash out the infected joint.
Resting the joint, raising it above heart level, and using cool compresses may help relieve pain. After the joint starts to heal, exercising it can help speed up recovery. Physical therapy is often useful for building up muscle strength and restoring movement.
Recovery is good with prompt antibiotic treatment. If treatment is delayed, permanent joint damage may result. Preventive antibiotics may be helpful for people at high risk.
When to see a doctor
Contact a doctor as soon as you notice symptoms of septic arthritis, such as a swollen, painful joint with a fever. Waiting matters, because delayed treatment may cause permanent joint damage. A baby who cries when a joint is moved, or who cannot move an arm or leg, needs to be seen too.
Call 911 or go to the emergency room if you have a sudden change in mental status, such as confusion, or if you faint.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. Either kind of doctor can examine you, order first tests, and send you to a specialist quickly if a joint infection is possible. They can also help with follow-up care after treatment.
Common questions
What causes septic arthritis?
Septic arthritis is caused by a bacterial or fungal infection in a joint. Most sudden cases are caused by Staphylococcus or Streptococcus bacteria.
How is septic arthritis treated?
Septic arthritis is treated with antibiotics. Some people also need the joint fluid drained with a needle or surgery.
Which joints does septic arthritis affect?
Septic arthritis commonly affects the knee and hip. It is usually in just one joint.
Can septic arthritis cause permanent damage?
Yes, permanent joint damage may result if treatment is delayed. Recovery is good with prompt antibiotic treatment.
Who gets septic arthritis?
Septic arthritis may be seen at any age. In children, it occurs most often in those younger than 3 years.
Sources
- MedlinePlus - Septic arthritis
- National Organization for Rare Disorders (NORD) - Arthritis, Infectious
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
