Swelling, or edema, is the result of fluid buildup that gets trapped in your body's tissues. Fluid buildup can occur when an area of the body becomes inflamed, injured or damaged. The small blood vessels in the body begin to leak fluid. Moreover, the body can bring in white blood cells to repair the damage, and more fluid follows. Depending on the cause, the swelling can be generalized and occur throughout the body, or localized and only affect a specific part of the body.

Common characteristics of a swollen shoulder

A swollen shoulder is often associated with trauma or injury. Take note of the associated symptoms below if you think you may be experiencing a swollen shoulder:

Pain
Bruising in the shoulder area
Warmth or redness of the affected area
Limited range of motion
Decreased strength
A feeling of instability in the shoulder
A visibly deformed or out-of-place shoulder

Seek prompt medical attention if you suspect shoulder swelling as it is often a sign of an underlying injury or chronic condition.

What causes a swollen shoulder

The shoulder is a very mobile joint and vulnerable to injury. The shoulder joint consists of the shoulder blade (scapula), the collarbone (clavicle) and the bone of the upper arm (humerus). The head of the humerus sits in a socket of the scapula (glenoid). There is a ring of tissue that surrounds the glenoid socket (labrum) that keeps all of these pieces in place.

See this image for a visual representation.

Any condition that causes inflammation, injury or damage to this system can result in shoulder swelling.

Trauma/Injury

Any activities that cause direct trauma to the shoulder area can result in these symptoms. Traumatic injuries include:

Falling on an outstretched arm
Direct blow: A direct blow to the shoulder can resultfrom a motor vehicle accident or even falling from a bicycle.
A sudden, forceful pull: For example, when trying to lift a heavy object from the ground.
Displacement or dislocation: This can occur in the system of bones, sockets, and tissue of the shoulder, causing the shoulder to feel as if it has popped out of place.

Overuse

Activities that cause repetitive shoulder motions such as tennis or weightlifting can cause an overuse injury to the shoulder joint. Repetitive overhead motions you may perform at work can also cause such overuse injuries and lead to symptoms of swelling and pain.

Aging

Shoulder swelling can be due to processes that occur as you age, such as the following.

Normal wear-and-tear: Wear-and-tear over a long period of time can weaken the shoulder joint. As a result, people over the age of 40 are more susceptible to such symptoms. With advanced age, the greater the exposure to situations that weaken the shoulder system lead to a breakdown of the tissues and ligaments surrounding the joint.
Rheumatologic: This category includes inflammatory conditions involving the body's tissues and joints that often affect people of older age. Conditions such as arthritis cause inflammation that easily brings fluid into the tissues, leading to swelling, redness, and tenderness in the joints.

This list does not constitute medical advice and may not accurately represent what you have.

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Acromioclavicular (ac) shoulder joint injury

The shoulder is made up of three bones - the shoulder blade (scapula), collar bone (clavicle), and arm bone (humerus). The acromioclavicular (AC) joint is a joint that is in the front of the shoulder, where the collar bone and shoulder blade meet. This joint is stabilized by ligaments, which can tear if the two bones are separated from one another. This is most commonly caused by falling on the shoulder.

Rarity: Rare

Top Symptoms: constant shoulder pain, pain in one shoulder, shoulder pain from an injury, shoulder pain near the end of the collarbone, difficulty moving the shoulder

Symptoms that always occur with acromioclavicular (ac) shoulder joint injury: shoulder pain near the end of the collarbone, constant shoulder pain

Urgency: Primary care doctor

Shoulder strain

Shoulder strain means that the muscles and/or the tendons in the shoulder have been overstretched to the point of damage and sometimes partial tearing. (A "sprain" means that ligaments have been damaged.)

Because of its wide range of motion, the shoulder is a relatively unstable joint that is vulnerable to injury. A sudden overloading, especially after long periods of overuse, can finally cause some degree of tearing to the muscle fibers and/or the tendons.

Shoulder strains are most often sports injuries, or are caused by strenuous physical labor.

Symptoms include sudden sharp pain followed by swelling, bruising, and ongoing tenderness.

Diagnosis is made through patient history, physical examination, and sometimes ultrasound.

Treatment involves a short period of rest, followed by gradually increasing exercise to regain strength and prevent stiffness and weakness of the muscles and tendons. Physical therapy will be tailored to the individual and some skills, such as for sports, may need to be relearned. Improving posture while sitting, and adjusting techniques for work and sports, can help prevent recurrence of the strain.

Rarity: Uncommon

Top Symptoms: pain in one shoulder, pain in the front of the shoulder, shoulder pain from overuse, shoulder pain from an injury, sports injury

Symptoms that always occur with shoulder strain: pain in one shoulder

Symptoms that never occur with shoulder strain: arm weakness, arm numbness

Urgency: Phone call or in-person visit

Shoulder bruise

A shoulder bruise, or contusion, means that the shoulder has been struck hard enough to damage the muscles without breaking the skin. This leaves a blue or purple mark in the skin that may be very sore.

A shoulder is most often bruised through a sports injury, such as blocking a player in a football game or falling from a horse. Using a rifle or shotgun can bruise the shoulder through the recoil.

A bruise may not seem serious, but it still needs proper care. It is possible for the bruise to mask a deeper injury such as a sprain, strain, or fracture. Complications such as compartment syndrome are possible, where trapped fluids from the damaged muscle tissues build up intense pressure and cause severe damage.

A medical provider can make an accurate diagnosis through physical examination and through imaging such as x-ray or CT scan.

Treatment for a shoulder contusion involves wearing a sling to take some pressure off of the shoulder joints; ice packs; and nonsteroidal anti-inflammatory drugs for pain and swelling.

Rarity: Rare

Top Symptoms: constant shoulder pain, pain in one shoulder, shoulder pain from an injury, shoulder injury, swelling of one shoulder

Symptoms that always occur with shoulder bruise: shoulder pain from an injury, shoulder injury, constant shoulder pain

Urgency: Self-treatment

Shoulder arthritis

Shoulder arthritis means that there is inflammation and abnormal wear of one or both of the two joints in the shoulder.

Arthritis in any joint is most often be caused by long-term wear and tear, called osteoarthritis; by an autoimmune condition that attacks the joints, called rheumatoid arthritis; or by an injury, called post-traumatic arthritis.

Symptoms include pain, which becomes worse with use of the joint; limited range of motion, meaning the shoulder joint cannot move as far as it once did; and pain when resting or trying to sleep.

Shoulder arthritis cannot be cured, but symptoms can be managed to improve quality of life and ease pain and discomfort.

Diagnosis is made through patient history, physical examination, and x-rays. To confirm, an injection of anesthetic may be placed into the joint. If the pain is eased, arthritis is almost certainly the cause.

Treatment involves physical therapy; nonsteroidal anti-inflammatory drugs to ease discomfort and inflammation; and corticosteroid injections into the shoulder to relieve pain. Surgery and shoulder joint replacement can be done in some cases.

Septic arthritis

Septic arthritis is also called infectious arthritis. "Arthritis" simply means inflammation of a joint. In septic arthritis, the inflammation is caused by a bacterial, viral, or fungal infection. The most common agent is Staphylococcus aureus, or staph.

These agents reach the joints either from another infection in the body, or from a traumatic injury that contaminates the wounded joint.

Risk factors include existing joint disease or injury; a weakened immune system; and damaged skin. All of these things allow infectious agents to get a foothold.

Symptoms include severe pain in the affected joints, along with redness and swelling. The knees are most often affected but septic arthritis can occur in any joint.

The infection can damage cartilage and bone very quickly, so anyone with these symptoms should see a medical provider as soon as possible.

Diagnosis is made through a sample of the joint fluid; blood tests; and x-ray or CT scan of the joint.

Treatment involves draining the infected fluid from the joint, either with a needle or with surgery, followed by antibiotics.

These agents reach the joints either from another infection in the body, or from a traumatic injury that contaminates the wounded joint.

Risk factors include existing joint disease or injury; a weakened immune system; and damaged skin. All of these things allow infectious agents to get a foothold.

Symptoms include severe pain in the affected joints, along with redness and swelling. The knees are most often affected but septic arthritis can occur in any joint.

The infection can damage cartilage and bone very quickly, so anyone with these symptoms should see a medical provider as soon as possible.

Diagnosis is made through a sample of the joint fluid; blood tests; and x-ray or CT scan of the joint.

Treatment involves draining the infected fluid from the joint, either with a needle or with surgery, followed by antibiotics.

Rheumatoid arthritis

Rheumatoid arthritis is a chronic inflammatory disorder that affects the lining of the joints, causing them to become thickened and painful. It can also affect other parts of the body such as the heart, lungs, eyes, and circulatory system.

Rheumatoid arthritis is an autoimmune disease, which means the body's immune system turns against itself for unknown reasons.

Most at risk are women from ages 30-60. Other risk factors are family history, smoking, and obesity.

Early symptom include warm, swollen, stiff, painful joints, especially the fingers and toes; fatigue; and fever. Usually, the same joints on both sides of the body are affected.

If untreated, irreversible joint damage and deformity can occur, with other complications. Early diagnosis can allow preventive treatment to begin as soon as possible.

Diagnosis is made through physical examination; blood tests; and x-ray, CT scan, or MRI.

There is no cure for rheumatoid arthritis, but the disease can be managed to improve quality of life. Treatment includes nonsteroidal anti-inflammatory drugs; steroids; anti-rheumatic drugs; physical therapy; and sometimes surgery to repair the joints.

Psoriatic arthritis

Psoriatic arthritis is a complication of psoriasis, which causes the skin to become thickened, red, and scaly. Arthritis may appear before or after the psoriasis appears.

Both conditions are autoimmune diseases, where the body attacks itself, and are thought to be caused by genetic and environmental factors.

Most susceptible are people from 30 to 50 years of age with a family history of the disease and who already have psoriasis.

Symptoms include the joints on one or both sides of the body becoming painful, swollen, and hot; swelling and deformity of the fingers and toes; pitted, flaking fingernails; foot pain in the heels and soles; and joint pain in the low back pain.

It is important to seek treatment, as psoriatic arthritis can permanently damage the joints, eyes, and heart.

Diagnosis is made through physical examination, x-rays, and MRI. Blood tests and joint fluid tests can confirm psoriatic arthritis.

Treatment includes over-the-counter, nonsteroidal anti-inflammatory drugs; anti-rheumatic medication; immunosuppressants; and steroid injections for the joints. Surgery to replace damaged joints may also be tried.

Biceps tendon rupture

The biceps muscle in the upper arm is anchored at the top by two separate tendons. One connects to the shoulder blade and one connects to the top of the shoulder joint. If one of these tendons is strained enough to completely tear it in two, this is called a biceps tendon rupture.

The injury is most common in people over age 40, especially after years of overuse of the shoulder. The person may have had episodes of biceps tendinitis in the past, which is a sign of fraying and damage to the tendon. In younger people it is primarily an acute sports injury, from weightlifting or from falling.

Symptoms include a pop or snap at the top of the shoulder, with sharp pain. There may soon be bruising halfway down the upper arm with obvious "balling up" of the partially disconnected muscle.

Diagnosis is made through patient history, physical examination, x-rays, and sometimes MRI.

Treatment involves over-the-counter anti-inflammatory medication; rest; ice; and physical therapy. Surgery may be done in some cases.

Rarity: Uncommon

Top Symptoms: pain in one shoulder, pain in the front of the shoulder, spontaneous shoulder pain, dull, achy shoulder pain, shoulder pain that gets worse at night

Symptoms that always occur with biceps tendon rupture: pain in the front of the shoulder, pain in one shoulder

Urgency: Primary care doctor

Swollen shoulder treatments and relief

When to see a doctor for a swollen shoulder

If you experience shoulder swelling or any of these associated symptoms, make an appointment with your physician to get appropriate treatment. Depending on the diagnosis, your physician may suggest:

Repositioning: If your swelling is due to a dislocation injury, your physician may first attempt to reposition the upper arm back into the shoulder socket. This is usually done with IV sedation in an emergency department or urgent care setting for acute dislocations.
Immobilization (sling): Your physician may use a sling to keep your shoulder from moving.
Physical therapy or rehabilitation: Your physician may prescribe stretching exercises or a physical therapy/rehabilitation program to help you restore range of motion, strength, and stability to your shoulder, especially after injury.
Rheumatologic medications: There are many types of medications that combat rheumatologic conditions that may be causing your swollen shoulder.

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Questions your doctor may ask about swollen shoulder

Is your swollen area warm and red?
Any fever today or during the last week?
What is your body mass?
How would you explain the cause of your shoulder pain?

Self-diagnose with our free Buoy Assistant if you answer yes on any of these questions.

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The stories shared below are not written by Buoy employees. Buoy does not endorse any of the information in these stories. Whenever you have questions or concerns about a medical condition, you should always contact your doctor or a healthcare provider.

Jeffrey M. Rothschild, MD, MPH.

Associate Professor of Medicine, Brigham and Women’s Hospital

Dr. Rothschild has been a faculty member at Brigham and Women’s Hospital where he is an Associate Professor of Medicine at Harvard Medical School. He currently practices as a hospitalist at Newton Wellesley Hospital. In 1978, Dr. Rothschild received his MD at the Medical College of Wisconsin and trained in internal medicine followed by a fellowship in critical care medicine. He also received an MP...

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