Reactive arthritis and septic arthritis are both associated with infections that are often caused by bacteria. However, the symptoms, causes, and treatments for each are different.

Arthritis refers to conditions that affect your joints, leading to symptoms like:

  • joint pain
  • joint swelling
  • reduced range of motion

There are over 100 different types of arthritis.

Reactive arthritis and septic arthritis are two types of arthritis that are associated with infections. However, there are important differences between these two types of arthritis which this article reviews.

While reactive arthritis and septic arthritis share some general symptoms, they each have some different symptoms, as well.

Symptom comparison chart

SymptomReactive arthritisSeptic arthritis
joint painYes, particularly at nightYes, severe
joint swellingYesYes
joint stiffness or reduced range of motionYes, often in the morningYes, severe
tendinitis or enthesitisYesNo
lower back or buttock painYesNo
eye symptomsYesNo
urinary symptomsYesNo

Symptoms of reactive arthritis

The symptoms of reactive arthritis typically come on 1–6 weeks after you’ve had an infection affecting your digestive system, urinary tract, or genitals. When symptoms do appear, they often do so suddenly.

Reactive arthritis typically occurs in the larger joints of your lower body, such as the knees and ankles. The affected joints are often on one side of the body. Joint-related symptoms include:

In addition to the joints, reactive arthritis can also impact other areas of the body, such as the eyes and urinary tract. Symptoms in these areas can include:

See a doctor if you develop symptoms consistent with reactive arthritis in the weeks after you’ve had a digestive, urinary tract, or genital infection. They can prescribe medications to help you manage your symptoms.

Symptoms of septic arthritis

Septic arthritis typically affects one joint, often a larger joint of your lower body, such as your knee or hip. However, in rare situations, multiple or smaller joints may be involved.

Symptoms of septic arthritis typically come on quickly and can include:

Seek immediate medical attention if you suspect septic arthritis

Septic arthritis can become serious and cause lasting damage to the affected joint. Seek immediate medical attention for joint pain and swelling that comes on suddenly and is associated with other symptoms like fever and chills.

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Both reactive arthritis and septic arthritis are associated with infections. However, their specific causes and risk factors are different.

Causes and risk factors for reactive arthritis

Reactive arthritis typically occurs after a bacterial infection. The types of infections associated with reactive arthritis are those affecting the digestive system, urinary tract, or genitals.

The cause of reactive arthritis is believed to be an autoimmune response following an infection. During this time, your immune system mistakenly attacks tissues, including those in the joint, that closely resemble bacterial markers.

Men ages 40 and younger are the group most commonly affected by reactive arthritis. Some additional risk factors include having an immune-related gene called HLA-B27 and having an HIV infection.

Causes and risk factors for septic arthritis

Septic arthritis happens when an infection in another part of the body spreads to joint tissue through the bloodstream. It can also occur via an injection or through an open wound due to an injury or a surgery.

The infections leading to septic arthritis are typically bacterial. However, they can also be fungal or viral.

Some of the risk factors for septic arthritis include having:

Common infectious agents of reactive arthritis

Common infectious agents of septic arthritis

Reactive arthritis and septic arthritis have different aspects to their treatment.

Treatment for reactive arthritis

There’s no cure for reactive arthritis. Instead, treatment aims to manage symptoms. This typically involves the use of medications to alleviate pain and swelling, such as:

Antibiotics may also be used if there’s evidence of an active infection when you see your doctor.

Physical activity is an important part of reactive arthritis treatment, as it helps to maintain or boost the function of the affected joints. Some people with reactive arthritis may benefit from engaging with a physical therapist.

In most people, reactive arthritis resolves in 6–18 months, although some people develop chronic arthritis in the affected joints. It’s also possible for reactive arthritis symptoms to return on repeat infection.

Treatment for septic arthritis

Septic arthritis can cause permanent joint damage and can also be fatal in some cases. As such, it requires immediate medical intervention.

Septic arthritis is treated using antibiotics if the infection is bacterial, as it often is. You may take these orally or receive them intravenously.

Treatment also involves drainage of the affected joint. This helps to remove infected synovial fluid and can reduce pain, swelling, and joint damage.

Physical therapy may be used during your recovery. This helps to restore function and strength to a joint that’s been damaged.

Reactive arthritis and septic arthritis are two types of arthritis that happen due to infections. These infections are often bacterial.

Both types of arthritis share typical arthritis symptoms like joint pain and swelling. However, reactive arthritis can have symptoms affecting the tendons, eyes, and urinary tract while fever and chills occur with septic arthritis.

It’s important to see a doctor promptly if you have symptoms of either reactive arthritis or septic arthritis. This is especially true for septic arthritis, which can become very serious and needs immediate treatment to prevent complications.