Reactive Arthritis

Overview

Reactive arthritis is an inflammatory joint condition that can develop after an infection in another part of the body, most often the digestive or urinary tract. The joints themselves are not usually infected; rather, the immune system reacts to the earlier infection and causes inflammation in the joints and sometimes in the eyes, skin, urinary tract, or other tissues.

Reactive arthritis is part of a group of rheumatology conditions known as spondyloarthritis, which can affect the spine, pelvis, and joints of the arms and legs. It may occur at any age, but it is more commonly seen in young and middle-aged adults. The condition can be short-term in some people, while others may have symptoms that come and go or last longer. With appropriate medical assessment and care, many people are able to manage symptoms and maintain daily activities.

Symptoms

Symptoms of reactive arthritis usually appear days to weeks after an infection. The pattern and severity can vary from person to person. Joint symptoms often affect the lower body, especially the knees, ankles, feet, or toes. Symptoms may be on one side or affect several joints.

• Joint pain, swelling, warmth, or stiffness
• Pain in the heel, sole of the foot, or around tendons
• Lower back or buttock pain, sometimes worse after rest
• Swelling of an entire finger or toe, sometimes called “sausage digit”
• Eye redness, pain, irritation, or sensitivity to light
• Pain or discomfort when passing urine
• Skin changes, including rashes on the soles, palms, or other areas
• Mouth ulcers or general fatigue

Not everyone has all of these symptoms. Some people mainly notice joint problems, while others may also have eye or urinary symptoms. Eye pain, marked redness, or changes in vision should be assessed promptly.

Causes and Risk Factors

Reactive arthritis is triggered by an immune response after certain infections. These infections may involve the intestines, often after foodborne illness, or the urinary and genital tract, often related to sexually transmitted infections. In many cases, the original infection may have been mild or already improved by the time joint symptoms begin.

The condition is not caused by “wear and tear” of the joints. It is also not usually contagious as arthritis itself. However, the infection that triggered it may be transmissible depending on the source, such as some genital infections or food-related infections.

Factors that may increase risk include a recent digestive or urinary tract infection, certain genetic predispositions, and a personal or family history of related inflammatory conditions. Having a risk factor does not mean a person will develop reactive arthritis, and people without known risk factors can still be affected.

Diagnosis

Diagnosis is based on a medical evaluation that considers symptoms, recent infections, physical examination findings, and test results. A rheumatologist or other qualified doctor may ask about recent diarrhea, urinary symptoms, sexual health history, eye symptoms, skin changes, travel, food exposures, and family history.

There is no single test that confirms reactive arthritis in every case. Tests may be used to support the diagnosis and to rule out other conditions such as septic arthritis, gout, other autoimmune diseases, or injuries. These may include blood tests to look for inflammation, urine or swab tests for infection, stool tests if digestive infection is suspected, and imaging such as X-rays or ultrasound when needed. In some cases, fluid may be taken from a swollen joint to check for infection or crystals.

Because reactive arthritis can resemble other joint diseases, professional assessment is important, especially if symptoms are persistent, severe, or involve the eyes.

Treatment Options

Treatment depends on the symptoms, the suspected trigger, the joints involved, and the overall health of the patient. The goals are to reduce inflammation, relieve pain, treat any active infection if present, maintain mobility, and prevent complications.

• Managing inflammation and pain: Doctors may recommend anti-inflammatory or pain-relieving medicines appropriate for the individual. In some cases, medication may be given directly to a severely inflamed joint.
• Treating infection: If an active infection is identified, the doctor may prescribe appropriate treatment. Partners may also need assessment in cases related to sexually transmitted infections.
• Physical therapy: Guided exercises can help maintain joint movement, strengthen supporting muscles, and reduce stiffness. Activity plans are usually adjusted to the level of inflammation.
• Eye care: Eye inflammation may require assessment by an eye specialist, especially if there is pain, light sensitivity, or vision changes.
• Longer-term care: If symptoms persist or recur, a rheumatologist may consider additional treatments that help control the immune system and reduce ongoing inflammation.

Lifestyle measures such as rest during flare-ups, gradual return to activity, joint protection, and safe sexual and food hygiene practices may support recovery and reduce the risk of triggering infections. Patients should follow medical advice rather than attempting to manage persistent symptoms on their own.

When to See a Doctor

Medical evaluation is recommended if joint pain or swelling develops after a recent digestive or urinary infection, or if joint symptoms are accompanied by eye redness, urinary discomfort, skin changes, or fever. Early assessment can help identify the cause and guide appropriate treatment.

Seek urgent medical care if a joint becomes very swollen, hot, and painful; if there is high fever; if walking becomes difficult; or if there is eye pain, severe redness, sensitivity to light, or any change in vision. These symptoms may indicate conditions that need prompt attention.

People with ongoing joint stiffness, repeated flare-ups, or symptoms lasting more than a few weeks should consider seeing a rheumatology specialist. A coordinated approach can help manage symptoms, monitor for complications, and support daily function.