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Reactive arthritis: the signs after an infection, who gets it, getting a diagnosis, treatment, and living with it
For anyone whose knee, ankle or heel started to hurt and swell a few weeks after a stomach bug, food poisoning, a bladder infection or a sexually transmitted infection; anyone with sore joints and red eyes or burning when they pee; and anyone just told they have reactive arthritis. The National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS, part of the NIH) says reactive arthritis is a reaction to a bacterial infection, that the symptoms typically start 1 to 6 weeks later, usually after the infection is gone, and that they often clear up on their own within a few weeks or months. This page passes on, by name, what NIAMS says: the signs in the joints, heel and toes, eyes and urinary tract; what sets it off and who gets it; the exam and the tests; the medicines by kind and physical therapy; and living with it. It builds the words to say to a provider, and prints a card for the visit.
A word with a dotted line under it, like this, opens its official definition, quoted from a U.S. government glossary.
Right now
- You suddenly cannot see, or someone is very ill and confused or hard to wake: call 911 (ours).
- A joint is suddenly hot, red and very swollen and you have a fever or chills: go to an emergency room or urgent care today (ours). NIAMS says a joint fluid test helps rule out other causes of joint pain, such as a joint infection.
- An eye hurts and your sight is blurry, or light hurts your eyes: see an eye doctor or go to an emergency room today (ours). NIAMS says uveitis, an inflammation inside the eye, can come with reactive arthritis.
- Thinking about suicide: call or text 988, any time.
More help
- Related: Arthritis · Psoriatic arthritis · Ankylosing spondylitis · Gout · Back pain · Pain, bones and joints.
- The infection: Food poisoning · Bladder infection · Sexually transmitted infections · HIV.
- Eyes: Pink eye · Eye care.
- Day to day: Symptom diary · Medicines list · Pain that lasts.
- Care and costs: When you need a doctor and can’t pay · When medicine costs too much · Get ready for the appointment.
- In a crisis: Help right now (988, 911). All our free tools.
Pain, a bone or a joint, and not sure this is the right page? The pages on this site for back pain, arthritis, pain that lasts, headaches, broken bones and sickle cell, on one list.
This page and its wording were written with AI (Claude) for Scarlet Beast (our AI policy). No doctor, nurse or therapist has reviewed it. The facts were read on October 15, 2026 on NIAMS’s Reactive Arthritis page, both parts: Overview, Symptoms, & Causes and Diagnosis, Treatment, & Steps to Take (NIH, last reviewed May 2024), and on its Spanish twin, Artritis reactiva (August 2024). Ours: going to an emergency room or urgent care today for a joint that is suddenly hot, red and very swollen with a fever or chills; seeing an eye doctor or going to an emergency room today for an eye that hurts with blurry sight or light that hurts; calling 911 when sight is suddenly lost or someone is very ill and confused or hard to wake; getting tested and treated for an infection now, and having a partner tested for a sexually transmitted one; telling the provider about a recent infection; keeping up HIV medicine; not stopping a prescribed medicine on your own; asking a pharmacist about an over-the-counter medicine; writing down what happens; asking what a test or medicine would change, its risks and what it costs; 988; and the order of the steps. What we left out: any medicine’s name or dose, any treatment NIAMS does not name, any diet, supplement, remedy or product, older names for the condition, and NIAMS’s research pages. This page saves nothing and loads no trackers.