Overview
Bursitis is inflammation of one or more bursae, the small fluid-filled sacs that reduce friction between moving tissues. When a bursa becomes irritated it can fill with extra fluid and swell, producing pain and limiting range of motion. Although often mild and temporary, bursitis can become chronic or infected in some cases.

Anatomy and common locations

Bursae sit between soft tissues such as muscles, tendons and bones to allow smooth movement. Their role is to help you move without pain. Typical sites for bursitis include the shoulder (subacromial bursa), the hip (trochanteric bursa) and other pressure points. Less commonly but often noticed are bursae at the elbow (elbow), in front of the kneecap (knee), and near the big toe (toe).

Causes and risk factors

Bursitis most often stems from repetitive motion or prolonged pressure on a joint. Other contributors include sudden injury, aging, poor posture, muscle imbalance, and underlying medical conditions such as rheumatoid arthritis, gout or diabetes. Rarely, bacteria can infect a bursa (septic bursitis), which requires prompt medical treatment.

Symptoms and diagnosis

Typical symptoms are localized pain, swelling, tenderness, warmth over the affected bursa, and limited movement of the nearby joint. Symptoms tend to worsen with activity that stresses the bursa. Clinicians diagnose bursitis by medical history and physical exam; imaging such as ultrasound or MRI can help in unclear cases. Fluid can be aspirated from a bursa to test for infection or crystals.

Treatment and prevention

  • Conservative care: rest, ice, compression, elevation, and over-the-counter anti-inflammatory medications.
  • Physical therapy: stretching and strengthening to correct mechanics and reduce recurrence.
  • Interventions: corticosteroid injections to reduce inflammation, aspiration to relieve pressure, and antibiotics if infection is present.
  • Surgery is uncommon but may be considered for chronic, resistant bursitis.

Preventive measures include ergonomic adjustments, protective padding over vulnerable bony areas, gradual progression of repetitive activities, weight control, and regular flexibility exercises.

Distinctions and when to seek care

Bursitis can resemble tendonitis or arthritis; a clinician distinguishes these by location, exam findings, and sometimes imaging or fluid analysis. Seek prompt medical attention if pain is severe, swelling rapidly increases, you develop fever, or there are signs of infection such as redness and warmth—these may indicate septic bursitis requiring antibiotics or drainage.