A cortisone injection into the shoulder is a common medical procedure used to treat pain and inflammation in joints, tendons, or bursae. The injection combines a corticosteroid, which provides the long-term anti-inflammatory effect, and a local anesthetic, which offers immediate but temporary pain relief. The corticosteroid mimics cortisol, a naturally occurring hormone, to reduce swelling by interacting with cells in the joint’s lining. Understanding the physical experience and necessary care afterward is important for a successful outcome.
The First 48 Hours
Patients often feel significant, rapid relief immediately following the injection due to the local anesthetic. This initial numbness and pain reduction typically lasts only for a few hours before the anesthetic wears off completely. Once the numbing agent dissipates, the shoulder may feel sore because the corticosteroid has not yet begun its anti-inflammatory work.
A temporary increase in pain, warmth, or soreness at the injection site, known as a “cortisone flare,” is a common reaction. This flare is caused by the crystallization of the medication within the joint, which temporarily irritates the surrounding tissue. The discomfort usually peaks within the first 24 to 48 hours and is a normal, expected response. Management involves applying ice packs to the area and, with a doctor’s approval, using over-the-counter pain relievers.
Activity Restrictions and Immediate Care
Resting the treated shoulder is important for the first 24 to 48 hours to allow the medication to settle effectively and minimize irritation. Patients should avoid strenuous activity, heavy lifting, or repetitive shoulder movements during this initial period. Overusing the shoulder while the anesthetic is masking the pain can disrupt the therapeutic process or cause further strain.
Driving should be restricted if the injected arm is the dominant one or if movement is significantly limited or painful. Avoid submerging the shoulder in water, such as in a bathtub, hot tub, or pool, for at least one to two days. Applying heat to the area, such as a heating pad, should also be avoided, as heat may increase blood flow and potentially exacerbate post-injection inflammation.
Timeline for Therapeutic Relief
The immediate relief from the local anesthetic is separate from the action of the corticosteroid, which requires time to reduce inflammation. The anti-inflammatory effects of the cortisone typically begin once the initial post-injection soreness or flare subsides. Most patients begin to notice genuine therapeutic improvement approximately three to seven days after the procedure.
Relief usually progresses gradually, with the shoulder pain and swelling steadily decreasing over the following days and weeks. The duration of the benefit is variable, but the pain relief from a single shot can last anywhere from several weeks up to several months. The injection is often used to create a “window of opportunity” where reduced pain facilitates effective participation in physical therapy and rehabilitation exercises. This allows patients to strengthen the shoulder joint and improve function without the limiting factor of intense pain.
Recognizing Normal vs. Warning Signs
While the cortisone flare is a common, temporary side effect, other minor systemic reactions can occur as the medication absorbs into the body. These expected, non-threatening side effects may include temporary facial flushing or a feeling of warmth in the face and chest. Diabetic patients may experience a temporary elevation in blood sugar levels, requiring more frequent monitoring for the first 48 hours.
It is important to differentiate these minor reactions from signs of a serious complication, such as an infection, which requires immediate medical attention. Warning signs include a fever, chills, or severe pain that is significantly worse than the expected flare and continues to worsen beyond 48 hours. Persistent, increasing redness, warmth, or swelling at the injection site that does not improve with ice must be reported to a healthcare provider promptly.