Side effects of a cortisone injection include weakened or ruptured tendons, local bleeding from broken blood vessels, and soreness, atrophy or depigmentation of the skin at the injection site. Some people may experience postinjection flare, which is an aggravation of inflammation caused by a reaction to corticosteroid medication, notes WebMD.
Potential long-term risks associated with cortisone injections include weight gain, puffiness of the face, easy bruising and thinning skin. Some people may also be at risk of increased blood pressure, thinning of the bones, damage to the bones of the large joints, and the forming of cataracts. Although side effects are possible, they are rare, notes WebMD.
Possible complication risks of cortisone injections include death or thinning of a bone in the same proximity as the shot, damage to nerves, infected joints, and deteriorated cartilage in a joint, states Mayo Clinic. Because cortisone injections may increase blood sugar levels, it is important that people with diabetes make sure the doctor is aware of the diabetes before the shot is administered, states WebMD
If a patient has an underlying condition, cortisone injections may inhibit the body's ability to fight infections. They may also mask or increase the severity of an infection. People with existing conditions, especially those related to blood clotting, should make the physician aware of their condition before getting the shot, according to WebMD.
Cortisone injections can be administered in either joint or soft tissue sites. Cortisone injections are useful for conditions, such as osteoarthritis, tendinitis, gout and Morton's neuroma, according to Mayo Clinic.