Bursitis is the inflammation of a bursa, a small fluid-filled sac that cushions the spaces between bones, tendons, and muscles near your joints. Your body has more than 150 of these sacs, and when one becomes irritated or swollen, the result is pain, stiffness, and sometimes visible swelling at the affected joint. The most common locations are the shoulder, elbow, hip, knee, heel, and the base of the big toe.
What a Bursa Does
A bursa works like a tiny water balloon wedged between hard and soft tissues. It reduces friction so that tendons and muscles can glide smoothly over bone every time you move. Without bursae, simple actions like lifting your arm or bending your knee would grind soft tissue against bone, causing constant irritation. When a bursa is healthy, you never notice it. When it becomes inflamed, the sac fills with excess fluid, swells, and the surrounding area becomes painful to move or even touch.
Common Causes
The most frequent trigger is repetitive motion or sustained pressure on a joint. Kneeling on a hard floor for hours, throwing a ball overhead repeatedly, or leaning on your elbows at a desk can all irritate a bursa over time. Occupational research has identified awkward or static postures, heavy physical labor, repetitive arm movements, and working with arms held above the shoulders as significant risk factors, particularly for shoulder bursitis. Sports like swimming, tennis, and baseball pitching carry similar risks.
A sudden injury, such as a hard fall onto your knee or hip, can also inflame a bursa in one blow rather than over weeks or months. Other contributing factors include age (bursae become less resilient over time), inflammatory conditions like rheumatoid arthritis or gout, and infections that reach the bursa through broken skin.
What Bursitis Feels Like
The hallmark symptom is a dull, achy pain at or near the affected joint that gets worse with movement or pressure. You might notice stiffness when you try to use the joint, especially first thing in the morning or after sitting for a long time. The area can feel tender to the touch, and in superficial locations like the elbow or kneecap, you may see visible swelling or redness. Many people report that pain is worse at night, particularly when lying on the affected side in cases of hip or shoulder bursitis.
Because bursae sit so close to tendons and joints, bursitis often feels like joint pain and is frequently mistaken for arthritis or tendonitis. The symptoms overlap considerably: both bursitis and tendonitis cause pain and stiffness that worsens with movement. The key difference is location. Tendonitis affects the cord of tissue connecting muscle to bone, while bursitis affects the cushioning sac nearby. In practice, the two conditions sometimes occur together.
Where Bursitis Occurs Most Often
Shoulder bursitis typically flares when you reach overhead or behind your back. The bursa sits between the rotator cuff tendons and the bony tip of the shoulder, and repetitive overhead motions compress it. Hip bursitis usually involves the bursa on the outer point of the hip bone (the greater trochanter). Pressing on that spot produces sharp tenderness, and the pain often radiates down the outer thigh. It is common in runners and in people who sleep on one side.
Elbow bursitis affects the bursa at the point of the elbow, sometimes swelling enough to look like a golf ball under the skin. This is common in people who rest their elbows on hard surfaces for long periods. Knee bursitis can strike in front of the kneecap (often called “housemaid’s knee” from prolonged kneeling) or on the inner side just below the joint. Heel bursitis develops near the Achilles tendon, where pain increases when the area is squeezed from side to side.
How Bursitis Is Diagnosed
Most of the time, a physical exam is all that’s needed. Your doctor will press on the area around the joint, ask you to move it in specific directions, and note where the pain occurs. For hip bursitis, for example, pressing over the outer hip bone typically produces sharp tenderness, and pain worsens when you try to push your leg outward against resistance. For knee or elbow bursitis, visible swelling often makes the diagnosis straightforward.
Imaging is usually unnecessary. When the diagnosis is uncertain, ultrasound can confirm fluid buildup in the bursa and help guide a needle if the fluid needs to be drawn out for testing. MRI is reserved for cases where a doctor needs to rule out a deeper injury inside the joint itself, such as a tendon tear, or when a mass needs further evaluation.
When Bursitis May Be Infected
Most bursitis is caused by mechanical irritation, not infection. But bacteria can enter a bursa through a cut, scrape, or puncture wound in the overlying skin, leading to septic bursitis. This is more common in superficial bursae like those at the elbow and kneecap. A fever alongside a swollen bursa is a strong indicator of infection, though the absence of fever doesn’t rule it out.
One reliable sign is warmth over the swollen area. Research published through the American Academy of Family Physicians found that a skin temperature difference of more than 2.2°C between the affected bursa and the same spot on the opposite, unaffected side predicted septic bursitis with 100% sensitivity and 94% specificity. People with diabetes, rheumatologic disorders, or a history of recent needle aspiration at the site are at higher risk. Septic bursitis requires prompt medical treatment because the infection can spread.
Treatment and Recovery
The first step is removing whatever caused the irritation. If kneeling triggered it, stop kneeling. If overhead lifting is the culprit, take a break from that movement. This rest period is the single most important part of recovery, and cutting it short is the most common reason bursitis lingers or returns.
While the bursa heals, standard home care includes icing the area to reduce swelling, elevating the affected limb, and taking over-the-counter anti-inflammatory pain relievers like ibuprofen or naproxen. Applying heat, or alternating between ice and heat, can also help. For joints that are hard to rest naturally, a splint, sling, or brace keeps the area supported and limits irritating movements. Recovery timelines vary widely depending on the location and severity, from a couple of weeks for a mild case to several months for a stubborn one.
If conservative measures don’t resolve the problem, a doctor may drain excess fluid from the bursa with a needle or inject a corticosteroid to reduce inflammation more aggressively. These injections are generally reserved for chronic or recurrent cases that haven’t responded to rest and anti-inflammatory treatment. In rare situations where bursitis keeps coming back despite other interventions, surgical removal of the bursa is an option.
Preventing Bursitis
Since repetitive pressure is the most common cause, the most effective prevention is reducing that pressure. Wear knee pads if your work or hobby requires kneeling. Use cushioned elbow rests if you spend hours at a desk. Take regular breaks from any repetitive motion, especially overhead arm work.
For hip bursitis, seating adjustments make a significant difference. An ergonomic chair with adjustable height that lets your feet rest flat on the floor, with knees at or slightly below hip level, keeps your pelvis in a neutral position and reduces strain on the hip bursae. Wedge cushions distribute your weight more evenly and lessen pressure on sore spots. When driving, tilting the seat slightly back and adjusting the height so your knees stay slightly bent can ease hip pressure on long trips.
Strengthening the muscles around vulnerable joints also helps. Stronger shoulder muscles stabilize the joint and reduce impingement on the bursa during overhead movements. Stronger hip and thigh muscles absorb more of the load that would otherwise fall on the bursa. Warming up before physical activity and gradually increasing intensity, rather than jumping straight into heavy or repetitive work, gives the bursae time to adapt.