Cortisone shots, also known as corticosteroid injections, are a common medical procedure designed to relieve pain and reduce inflammation in a targeted area of the body. The injection typically contains a corticosteroid medication, which mimics the anti-inflammatory effects of cortisol, a hormone naturally produced by the adrenal glands. They are primarily used to treat inflammatory conditions like arthritis, bursitis, and tendinitis in joints such as the knee, shoulder, or hip, providing relief that can last for several months. While cortisone shots are generally considered safe when administered correctly, concerns about potential adverse effects are valid and prompt a detailed look at the risks associated with this treatment option.
Immediate and Localized Reactions
The most frequent reactions occur directly at the injection site and are usually temporary. Many patients experience a post-injection flare, which is a short-term increase in pain and swelling in the joint or area that was injected. This flare is thought to be a reaction to the deposited corticosteroid crystals and typically resolves within one to two days following the procedure.
Other localized side effects involve the tissues surrounding the injection site, such as bruising from the needle insertion. In superficial injections, changes to the skin can occur, including depigmentation (whitening of the skin) or thinning of the skin and soft tissue (atrophy). These skin and soft tissue changes are generally cosmetic and often resolve within a year.
Providers often mix the steroid with a local anesthetic to provide immediate pain relief and help mitigate the temporary discomfort of the post-injection flare. Patients are usually advised to rest the area and apply ice for a day or two to manage these initial symptoms.
Systemic and Metabolic Concerns
A small amount of the corticosteroid is absorbed into the bloodstream, which can lead to temporary effects throughout the body, known as systemic side effects. One of the most common systemic effects is a temporary elevation of blood glucose levels, which is a particular concern for individuals with diabetes. Diabetic patients are advised to monitor their blood sugar closely for several days after the injection, as the steroid can induce a transient state of hyperglycemia.
The steroid can also temporarily influence the central nervous system, sometimes leading to short-term mood changes, such as mild anxiety, insomnia, or difficulty sleeping. Some people report experiencing facial flushing, characterized by redness and a feeling of warmth in the face and chest. These effects are usually transient, lasting only a day or two following the procedure.
Less commonly, the circulating steroid can temporarily suppress the body’s immune response, making it slightly more difficult to fight off an existing infection. For this reason, cortisone shots are generally avoided if a patient has an active infection. In rare cases of frequent or high-dose use, the shots can also lead to a temporary suppression of the adrenal glands.
Structural Risks Related to Frequent Use
The most significant concerns about long-term harm relate to the cumulative effect of the steroid on soft tissues, particularly when injections are repeated too often in the same area. Corticosteroids possess catabolic properties, meaning they can break down tissue, which poses a risk to structural components like tendons. Injecting directly into or repeatedly near a tendon can weaken the tissue, increasing the risk of a tendon rupture.
This weakening effect is particularly noted in high-stress, weight-bearing tendons, such as the Achilles and patellar tendons, leading many specialists to avoid injecting these structures entirely. The steroid inhibits collagen synthesis and promotes its degradation, undermining the tissue’s integrity and tensile strength.
Within a joint, repeated injections can potentially accelerate the progression of cartilage loss, a condition known as arthropathy. Studies have suggested that receiving cortisone shots frequently may contribute to the breakdown of cartilage over time. In rare instances, particularly with high-dose or frequent systemic use, there is also a risk of osteonecrosis, which is the death of bone tissue due to an interruption of blood supply.
Guidelines for Safe Administration
Medical guidelines exist to minimize the risks associated with cortisone injections, focusing on careful patient selection and procedural precision. To protect joint structures, most healthcare providers adhere to a practical limit of administering no more than three or four injections per year into the same joint.
Accurate placement of the medication is paramount, and many providers now use image guidance, such as ultrasound or fluoroscopy, to ensure the steroid is deposited precisely where intended. Using image guidance helps prevent the medication from leaking into surrounding healthy soft tissue, reducing the chance of local side effects like skin atrophy or tendon damage.
Furthermore, there are specific contraindications where the shot should be avoided, including the presence of an active infection near the injection site or a pre-existing fracture. Patients are screened for conditions that increase risk, such as poorly controlled diabetes or severe osteoporosis. When used thoughtfully as part of a broader treatment plan that includes physical therapy, cortisone injections can be a powerful tool for short-term pain relief.