People who get cortisone injections to reduce joint inflammation sometimes report side effects. Potential side effects include:

    Pain and swelling (cortisone flare). The injected cortisone medication can crystallize inside the body. The crystals can cause pain and inflammation that is worse than the pain and inflammation caused by the condition being treated. A cortisone flare typically lasts one or two days and can be treated with rest and intermittent cold packs.

    See When and Why to Apply Cold to an Arthritic Joint

    Skin discoloration. Some patients with darker skin may notice that the skin around the injection area becomes lighter. The discoloration can be permanent but is not harmful to patients' health.

    Elevated blood sugar. In addition to decreasing inflammation, corticosteroids can raise blood sugar levels. Patients with diabetes should closely monitor blood sugar levels for a day or two following a cortisone injection. (The injection does not deliver cortisone directly to the bloodstream, but it can still influence blood sugar levels in some patients.)


    Infection. Though rare, it is possible for the injection site to become infected. Patients who suspect an infection or run a fever should contact their doctor.

    Allergic reaction. Patients should tell their doctor if they have ever had an allergic reaction following an injection. While uncommon, some patients have allergic reactions to the local anesthetic added to the injection. Allergic reactions to the cortisone itself are rare because cortisone is a synthetic version of cortisol, a steroid naturally found in the body.

Doctors do not recommend cortisone injections for patients who have an existing infection, including skin infections and septic arthritis. In addition, cortisone injections may be inappropriate for patients who are taking blood thinners or who have broken bones.


Some patients may be concerned about weight gain and water retention from corticosteroid use. However, these side effects are common only for patients who take corticosteroid medications orally for an extended period of time. These side effects to not occur when the cortisone medication is injected into a joint.

See What Is Cortisone?

Read more articles about other types of injections in the Injections Health Center

Further Reading: Osteoarthritis Treatment