Also called: Septic arthritis
Important: This page is general information, not medical advice. It does not recommend or prescribe any treatment. Always consult your doctor or pharmacist before starting, stopping or changing any medicine.
About Infectious Arthritis
Most kinds of arthritis cause pain and swelling in your joints. Joints are places where two bones meet, such as your elbow or knee. Infectious arthritis is an infection in the joint. The infection comes from a bacterial, viral, or fungal infection that spreads from another part of the body. Symptoms of infectious arthritis include:
- Intense pain in the joint
- Joint redness and swelling
- Chills and fever
- Inability to move the area with the infected joint
One type of infectious arthritis is reactive arthritis. The reaction is to an infection somewhere else in your body. The joint is usually the knee, ankle, or toe. Sometimes, reactive arthritis is set off by an infection in the bladder, or in the urethra, which carries urine out of the body. In women, an infection in the vagina can cause the reaction. For both men and women, it can start with bacteria passed on during sex. Another form of reactive arthritis starts with eating food or handling something that has bacteria on it.
To diagnose infectious arthritis, your health care provider may do tests of your blood, urine, and joint fluid. Treatment includes medicines and sometimes surgery.
It sits within Bones, Joints and Muscles and Infections.
The lead U.S. institute for this subject is the National Institute of Arthritis and Musculoskeletal and Skin Diseases.
When to speak to someone. Reading about a topic cannot tell you whether it applies to you. Speak to a doctor or pharmacist if symptoms are severe, sudden, getting worse, or simply not going away — and seek emergency care immediately for chest pain, breathing difficulty, sudden weakness or confusion, or a serious allergic reaction.
Research on Infectious Arthritis
225 studies areregistered for this condition on ClinicalTrials.gov, the U.S. National Library of Medicine's public registry. A selection is below — the links go straight to the registry entry, not to a summary of ours.
What a registered study does and does not mean. Registration means a study exists and has been declared publicly. It says nothing about whether the treatment being tested works, is safe, or is available to you. Many studies find no benefit — that is what research is for. Never seek out an experimental treatment on the strength of a registry entry alone.
Research currently under way
- Trimethoprim-sulfamethoxazole vs. Clindamycin for the Treatment of Children With Invasive MRSA InfectionsIndiana University
- Alpha-Defensin and Synovial Proteins to Improve Detection of Pediatric Septic ArthritisHospital for Special Surgery, New York
- Safety and Immunogenicity of the Live Attenuated Tetravalent Butantan-Dengue Vaccine in Autoimmune Rheumatic DiseasesUniversity of Sao Paulo General Hospital
- A Study to Assess the Concentration of Bimekizumab in Mature Breast Milk From Mothers Receiving Treatment With Bimzelx® (Bimekizumab)UCB Biopharma SRL
- Antibiotic Impregnated Bone Graft to Reduce Infection in Hip Replacement.University Hospital, Linkoeping
- Persona Revision Knee System OutcomesZimmer Biomet
Research already completed
- Effect of Single vs Multiple Prophylactic Antibiotic Doses on PJI Following Primary THA in Patients With OASoren Overgaard
- Retention and Re-Engagement in Treatment for Addiction Following Serious Injection Related Infections (RETAIN)Boston Medical Center
- Prevalence of Pathogens in Synovial Fluid Obtained From Emergency Department PatientsOlive View-UCLA Education & Research Institute
- Modeling Spinal Mobility in Ankylosing Spondylitis: Towards New Telekinetic BiomarkersUniversity Hospital, Montpellier
- COVID-19 in Rheumatic Inflammatory Diseases Under Immuno-suppressive DrugsUniversity Hospital, Montpellier
- The Immunogenicity and Safety of Zostavax® and Shingrix® in Rheumatoid Arthritis Patients Using AbataceptKevin Winthrop
Study data from ClinicalTrials.gov, a service of the U.S. National Library of Medicine. Retrieved 2026-07-30. Registry entries are supplied by study sponsors and investigators; ClinicalTrials.gov does not verify their scientific validity. PocketsInfo is not affiliated with, and not endorsed by, the NLM or the NIH.
Where to read more
Rather than paraphrase, we point you to the primary sources. Every link below is to a government health agency, a national institute or a recognised medical body — grouped by what you are trying to find out.
Start Here
- Infectious ArthritisMerck & Co., Inc.
- Septic ArthritisMayo Foundation for Medical Education and Research
Diagnosis and Tests
- Bacteria Culture TestNational Library of Medicine
- Bone X-RayRadiological Society of North America
- C-Reactive Protein (CRP) TestNational Library of Medicine
- Complete Blood Count (CBC)National Library of Medicine
- Musculoskeletal MRIRadiological Society of North America
- Synovial Fluid AnalysisNational Library of Medicine
Treatments and Therapies
- Joint Injections (Joint Aspirations)American College of Rheumatology
Clinical Trials
- ClinicalTrials.gov: Arthritis, InfectiousNational Institutes of Health
- ClinicalTrials.gov: Arthritis, ReactiveNational Institutes of Health
Medical subject headings
Clinicians and researchers index this subject under Arthritis, Infectious. These are the terms to use when searching medical literature.
This page is built from the MedlinePlus health topic record for Infectious Arthritis, a service of the U.S. National Library of Medicine (NLM), National Institutes of Health. Information is from MedlinePlus.gov. PocketsInfo is not affiliated with, and is not endorsed by, the NLM or the NIH. Retrieved 30 July 2026.