Olecranon bursitis, also known as water on the elbow, is a common inflammation of the bursa sac used to help the elbow move smoothly under your skin. When the bursa becomes filled with fluid, the area will become swollen and painful. Knowing the possible causes of water on the elbow can help you determine the possible causes of elbow pain.
One common cause of water on the elbow is an injury. Any type of trauma to the elbow can cause fluid to collect. For example, falling and landing on your elbow or being struck in the elbow can cause it to fill with fluids. The injury can be as simple as hitting your elbow on the edge of a table or a doorway as you walk through it. Virtually any hard knock right on the bursa can cause it to swell and produce fluids.
Like a sudden trauma, repetitive trauma will cause the bursa to swell and fluid to accumulate. A common example is throwing a baseball over and over again. The bending and extension of the elbow can inflict minor damage to the elbow, causing fluid to accumulate over time. Another example is the rubbing of your elbow across your desk as you are writing. Along with repetitive trauma is extended pressure. This often occurs when you sit for long periods of time at a desk with your elbow resting on the arms of the chair or from leaning on your elbow on a table top. Unlike sudden trauma, both of these types of trauma generally take several months to develop.
Water on the elbow can also be caused by a scratch or insect bite. When bacteria enter such an opening, an infection can occur. Once the bursa is infected, it produces both fluid and pus. Usually with an infection, the area becomes red as well.
Other Medical Conditions
Certain medical conditions, such as rheumatoid arthritis and gout, can also cause fluid to accumulate on the elbow. These conditions make the collection of fluid on the bursa a much more common occurrence and do not require any type of trauma, injury, or infection.