What Exactly Is Shoulder Bursitis?

To understand shoulder bursitis, we first need to know what a bursa is. A bursa is a small, thin, jelly-like sac filled with a tiny amount of fluid. You have bursae in many of your joints, and their job is to act as a cushion and reduce friction between moving parts, like bones, muscles, and tendons. Think of it as a smooth, gliding surface that allows everything to move without rubbing against each other.

Your shoulder is a very mobile joint with several bursae to help it move smoothly. The bursa most commonly involved in shoulder bursitis is the subacromial bursa. It sits in the space below the top of your shoulder blade (a bone called the acromion) and above the rotator cuff tendons. Every time you lift your arm, this bursa helps your tendons glide freely under the bone.

In a healthy shoulder, you are not aware of your bursae. They are very thin and do their job quietly. However, if the shoulder experiences too much friction, pressure, or an injury, the bursa can become irritated and inflamed. This is shoulder bursitis. The inflamed bursa thickens and can fill with excess fluid, turning from a slick cushion into a swollen, painful sac.

When the bursa swells, it takes up more room in an already tight space. This swollen bursa can get pinched between the bones when you move your arm, causing more pain and irritation. This can create a painful cycle. Often, the nearby rotator cuff tendons are also affected and can become inflamed (a condition called tendinitis). This is because the same forces that irritate the bursa often stress the tendons as well. Doctors sometimes refer to the combination of bursitis and tendon irritation as shoulder impingement syndrome. Whether it’s called bursitis, impingement, or tendinitis, it often points to the same underlying issue: an over-stressed shoulder joint with inflamed tissues causing pain.

Types of Shoulder Bursitis

Doctors often classify shoulder bursitis into a few different types based on how it starts and what is causing it.

Chronic Shoulder Bursitis

This is the most common type. "Chronic" means it occurs repeatedly or lasts for a long time. It usually develops from repetitive irritation or overuse of the shoulder. You might find that your shoulder gets irritated, feels better with rest, and then becomes painful again when you return to the activity that caused it. People with chronic bursitis may have experienced similar shoulder pain on and off in the past. It’s a nagging issue that can flare up periodically if the underlying cause isn’t addressed.

Acute (Traumatic) Shoulder Bursitis

"Acute" means the condition comes on suddenly, often after a specific injury. A fall on your shoulder, a direct blow, or lifting something too heavy can trigger acute inflammation of the bursa. This is sometimes called traumatic bursitis. The pain tends to appear quickly, within hours or a day of the injury. If the shoulder is otherwise healthy, acute bursitis can be a one-time event that improves as the injury heals with proper rest and care.

Infectious (Septic) Shoulder Bursitis

This is a rare but serious type of bursitis that occurs when the bursa becomes infected with bacteria. An infection can happen if bacteria spread through your bloodstream from another part of your body or if a puncture wound introduces germs directly into the bursa. Septic bursitis is more common in joints closer to the skin's surface, like the elbow, but it can happen in the shoulder. With an infected bursa, the shoulder may become very red, swollen, and warm. You might also have a fever and feel generally unwell. This condition requires immediate medical attention, as the infection can become dangerous if it spreads.

Causes and Risk Factors

Shoulder bursitis can happen for many reasons, often involving a combination of factors.

Why Does It Happen?

• Repetitive Stress and Overuse: This is the most common cause. When you perform the same shoulder motion over and over, especially overhead movements, the subacromial bursa can get irritated from friction. Athletes like baseball pitchers, swimmers, and tennis players are prone to this. People in certain jobs are also at risk, including painters, carpenters, and anyone whose work involves frequent lifting or reaching overhead. It’s the cumulative effect of small stresses that gradually inflames the bursa.
• Injury or Trauma: A direct blow to the shoulder or a fall can cause acute bursitis. A single event, like slipping on ice and landing on your shoulder, can be enough to trigger inflammation.
• Shoulder Anatomy and Structure: Some people are born with a shape of their acromion bone that gives less space for the bursa and tendons. A "hooked" acromion, for example, curves downward and can pinch the bursa more easily. Bone spurs, which are small bony growths that can form with age or from wear-and-tear, can also narrow the space and rub against the bursa, causing chronic irritation.
• Poor Shoulder Mechanics: How your muscles and shoulder blade move together matters. Abnormal movement of the shoulder blade (scapula), known as scapular dyskinesis, can throw off the coordination of the shoulder joint. This can be due to muscle imbalances or poor posture and can lead to extra friction and irritation of the bursa.
• Other Shoulder Problems: Shoulder bursitis can sometimes be a side effect of another shoulder injury. For example, a tear in a rotator cuff tendon can cause inflammation and fluid to build up, which in turn can irritate the bursa.
• Underlying Health Conditions: Certain systemic health issues can make you more prone to bursitis. Inflammatory conditions like rheumatoid arthritis or gout can cause bursae to become inflamed. Other conditions like diabetes and thyroid disease have also been linked to a higher risk of shoulder problems, including bursitis.

Who Is at Risk?

While anyone can get shoulder bursitis, some factors increase your risk:

• Repetitive Activities: Sports like baseball, tennis, and swimming, or jobs like painting and construction.
• Age: Bursitis becomes more common as we get older, often due to wear-and-tear.
• Previous Injuries: A past shoulder injury can leave you more susceptible to future problems.
• Poor Posture: Slouching can reduce the space in your shoulder joint, increasing the risk of impingement.
• Certain Health Conditions: Rheumatoid arthritis, gout, and diabetes can increase your risk.
• Lack of Conditioning: A sudden increase in activity without proper conditioning can overload the shoulder.

Symptoms to Look For

The signs of shoulder bursitis can range from a mild ache to severe pain. Here are the common symptoms:

• Shoulder Pain: The most common symptom is pain on the outer side or front of the shoulder. It’s often a dull, achy pain at rest that becomes sharp with certain movements, especially lifting your arm or reaching overhead. The pain might radiate a short way down your arm but usually doesn't go past the elbow.
• Limited Range of Motion: The pain can make it hard to move your arm freely. You might struggle to reach overhead, behind your back, or out to the side. The shoulder may feel stiff.
• Tenderness: The area around your shoulder, particularly on the outer side just below the bony tip, may be tender to the touch.
• Pain at Night: A key feature of shoulder bursitis is night pain. Lying on the affected shoulder can be very painful and may wake you up. Many people find the pain is worse at night, even when they are resting.
• A "Painful Arc": You might notice that the pain is worst when you lift your arm through a specific range of motion, typically between shoulder height and just above your head. This is known as a painful arc.
• Weakness: Your arm might feel weak, but this is often because it hurts to use the muscles. If you have significant weakness, it could be a sign of a more serious issue like a rotator cuff tear.
• Swelling or Redness: In most cases of subacromial bursitis, there is no visible swelling or redness because the bursa is deep under the muscle. However, if you do see significant redness, heat, and swelling, especially with a fever, it could be a sign of an infection that needs immediate medical care.

How Is Shoulder Bursitis Diagnosed?

A healthcare provider can usually diagnose shoulder bursitis based on your symptoms and a physical exam.

First, your doctor will ask about your pain, your activities, and your medical history. This helps them understand what might be causing the problem.

Next, they will perform a physical examination. They will look at your shoulder, press on different areas to find tender spots, and ask you to move your arm in various directions to test your range of motion and strength. They may perform specific tests, known as impingement tests, where they move your arm in a way that gently pinches the subacromial space. If this reproduces your pain, it strongly suggests bursitis or impingement.

In many cases, this is enough for a diagnosis. However, your doctor might order imaging tests to get more information or to rule out other problems.

• X-rays: An X-ray won’t show the bursa itself, but it can reveal bone spurs, arthritis, or other bone-related issues that could be contributing to the pain.
• Ultrasound or MRI: These tests create detailed images of the soft tissues, including the bursa and tendons. They can confirm that the bursa is inflamed and check for other problems like a rotator cuff tear.

If an infection is suspected, your doctor may need to draw fluid from the bursa with a needle (a procedure called aspiration) to test it in a lab.

Preventing Shoulder Bursitis

While not all cases can be prevented, you can take steps to reduce your risk, especially for overuse-related bursitis.

• Warm-Up and Stretch: Always warm up your shoulders before activity and stretch your shoulder and chest muscles to maintain flexibility.
• Strengthen Your Shoulder: Strong rotator cuff and shoulder blade muscles help the shoulder move correctly and reduce stress on the bursa.
• Use Proper Technique: Whether at work or during exercise, use good form to avoid unnecessary strain. Pay attention to your posture.
• Take Breaks: If you do repetitive tasks, pace yourself and take frequent breaks to give your shoulder a rest.
• Don't Push Through Pain: Pain is your body's signal to stop. Ignoring it can turn a minor issue into a major one.
• Increase Activity Gradually: Avoid sudden, intense increases in activity. Build up slowly to allow your shoulder to adapt.
• Maintain Overall Health: Managing chronic conditions like diabetes or arthritis can help reduce your risk of inflammatory flare-ups.

Recovery and Outlook

The good news is that the outlook for shoulder bursitis is generally excellent. Most cases resolve with proper care and without any long-term problems.

Recovery time can vary, but many people feel significant relief within a few weeks. More stubborn cases might take a couple of months to fully settle down. The vast majority of people get better with conservative (non-surgical) approaches like rest, activity modification, physical therapy, and other treatments your doctor might suggest. Surgery is rarely needed.

A full recovery, where you are pain-free with a normal range of motion, is a realistic goal for most people. Once you have recovered, it’s important to continue with stretching and strengthening exercises and to be mindful of the activities that may have caused the problem in the first place. This can help prevent it from coming back.

Shoulder bursitis can be painful and disruptive, but it is a temporary condition for most. By understanding the causes and symptoms, you can take the right steps to manage it and get back to your normal activities.