There can be several concurrent causes. Trauma, auto-immune disorders, infection and iatrogenic (medicine-related) factors can all cause<unk> .<unk>  is commonly caused by repetitive movement and excessive pressure. Shoulders, elbows and knees are the most commonly affected. Inflammation of the bursae may also be caused by other inflammatory conditions such as rheumatoid arthritis, scleroderma, systemic lupus erythematosus, and gout. Immune deficiencies, including HIV and diabetes, can also cause<unk> . Infrequently, scoliosis can cause<unk>  of the shoulders; however, shoulder<unk>  is more commonly caused by overuse of the shoulder joint and related muscles. Traumatic injury is another cause of<unk> . The inflammation irritates because the bursa no longer fits in the original small area between the bone and the functionary muscle or tendon. When the bone increases pressure upon the bursa,<unk>  results. Sometimes the cause is unknown. It can also be associated with various other chronic systemic diseases.
Bursitis
Adhesive capsulitis of the shoulder
Glossitis
Facet joint arthrosis
Enthesitis
Osteochondropathy
Calcific bursitis
Knee arthritis