Arthritis and other joint problems may be treated with cortisone injections. Like any treatment, these injections carry certain risks and side effects. Most are mild or temporary, but some can be serious or long-lasting.
Patients are advised to discuss concerns about risks and side effects with their health care providers before receiving cortisone injections. Potential risks and 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. This side effect is called a cortisone flare. A flare typically lasts one or two days and can be treated with rest and intermittent cold packs.
Patients may notice the skin around the injection site changes color a few weeks or months after the injection.1,2 This side effect is most common in darker-skinned patients, who notice the skin becomes lighter.1
Skin discoloration may last a few weeks or months or be permanent.2 Skin discoloration is not harmful to patients' health. This side effect occurs in 1.3% to 4% of patients3 and seems to be related to the type and concentration of corticosteroid medication used.1,2
A cortisone injection may cause fat cells at the injection site to atrophy. A divot or depression in the skin may appear because the underlying fat cells have deteriorated. The skin’s appearance usually goes back to normal in 6 months but may take 2 or 3 years.2 Authors of one study estimate this side effect occurs in 0.6% (6 out of every 1000) injections.4
Elevated Blood Sugar
In addition to decreasing inflammation, corticosteroids can raise blood sugar levels. A patient with diabetes should inform their doctor prior to receiving an injection and then 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.
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Cortisone injections can weaken nearby tendons and make them more prone to tearing.5 Because of this risk, physicians take precautions to avoid placing a cortisone injection in or directly next to a tendon.
Patients can reduce their risk of tendon injuries by resting the affected joint for a few days after the injection and then gradually increasing activity with recommended stretching and exercises.
Research suggests cortisone injections may have a negative effect on cartilage. For example, one study6 found an association between repeated cortisone injections and 0.11 cm loss of cartilage in the knee. The same study did not find an association with increased knee pain.
Though rare,7,8 infection is a serious potential side effect. People who are more prone to infection, such as those who have autoimmune diseases and who take immune-suppressing medications, should inform their health care provider. After receiving a cortisone injection, any patient who suspects an infection or runs a fever is advised to contact their doctor.
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.
Sex-Related Side Effects
While not common, women may experience9:
- Irregular menstruation
- Disturbances in lactation, if the woman is breast-feeding
- Skin flushing
- Excess hair growth
Unlike women, men do not seem to experience any unique side-effects.9
Doctors do not recommend cortisone injections for patients who have an existing infection, including skin infections and septic arthritis. In addition, cortisone injections may not be appropriate 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 rarely occur when the cortisone medication is injected into a joint.
Read more articles about other types of injections in the Injections Health Center