Cortisone Shot Side Effects: What the Evidence Shows
Cortisone shot side effects by incidence rate: skin atrophy, tendon rupture, infection risk, and blood glucose spikes in diabetic patients, sourced from peer-reviewed data.
None of this makes cortisone injections dangerous as a class. Orthopaedic and rheumatology literature treats them as a low-complication procedure overall. But "low-complication" is not the same as "no monitoring needed." The specific numbers matter more to a prescribing doctor or hospital administrator than a vague reassurance does. This piece works through the local reactions, the tendon and joint risks, the diabetic blood-glucose effect, and how often the same joint can reasonably be injected.
What is a post-injection flare after a cortisone shot?
A post-injection flare is a transient worsening of pain and swelling at the injection site in the first 24–48 hours, caused by a local reaction to the corticosteroid crystals rather than infection. It affects up to 25% of patients receiving extra-articular corticosteroid injections and typically resolves within two days without intervention Adverse effects of extra-articular corticosteroid injections: a systematic review.
The same systematic review found major adverse events after extra-articular corticosteroid injection ranging from 0% to 5.8% across studies. Minor adverse events, flare included, ranged far wider: from 0% to 81%, depending on injection site and follow-up method. That spread reflects inconsistent reporting across the literature more than a single stable rate.
A flare is clinically distinguishable from an infected joint mainly by timing: infection tends to present weeks later, not within 48 hours. Counselling a patient before discharge that some swelling is expected in the first two days reduces same-day return visits without masking a genuine complication.
Can a cortisone shot cause skin and fat atrophy at the injection site?
Yes. Subcutaneous fat atrophy and skin depigmentation are recognised local complications of corticosteroid injection, occurring when the drug diffuses along the needle track into surrounding tissue. Reported incidence varies widely by study design, from roughly 1.3–4% for hypopigmentation up to 40% in some prospective cohorts looking specifically for the sign Cutaneous complications following extra-articular corticosteroid injections: a prospective cohort study.
The depression this leaves in the skin can take six months to two or three years to resolve, and in some patients it never fully reverses The Use of Steroid Injections for Hand and Wrist Pathologies. It is cosmetic rather than functionally dangerous, but it is exactly the kind of complication patients remember and complain about later, which makes pre-injection counselling worth the thirty seconds it takes.
Superficial injections carry a materially higher visible-atrophy risk than deep intra-articular ones. A shot around the wrist, elbow, or dorsal hand has far less tissue depth to disperse the drug before it reaches the skin than an injection into a large joint like the knee or hip.
Do repeated cortisone injections weaken or rupture tendons?
Tendon rupture after corticosteroid injection is rare in absolute terms but biologically real: corticosteroids inhibit collagen synthesis in extracellular matrix and reduce local vascularity, weakening tendon structure with each exposure. Documented case reports exist, including a reported bilateral digital flexor tendon rupture following carpal tunnel corticosteroid injection The Use of Steroid Injections for Hand and Wrist Pathologies.
Oral corticosteroid exposure carries a clearer statistical signal than a single local injection does: population data puts the adjusted incidence rate ratio for any tendon rupture at 2.58, and for Achilles tendon rupture specifically at 4.59, compared with non-users Tendon Ruptures Associated With Corticosteroid Therapy. The mechanism is the same drug class; the exposure route differs.
Weight-bearing tendons, the Achilles and the patellar tendon in particular, get treated with more caution in most orthopaedic practice than non-weight-bearing sites. A rupture there is far more disabling than one in a finger flexor. Cumulative injection count into the same tendon, not a single shot, is what the evidence links to rupture risk.
How often can the same joint be safely injected with cortisone?
European rheumatology guidance generally caps corticosteroid injections into the same joint at three to four per year, spaced at least three months apart, to limit cumulative cartilage and soft-tissue exposure The Use of Steroid Injections for Hand and Wrist Pathologies. This is a practice convention drawn from cumulative-exposure reasoning rather than a single randomised trial defining an exact safe ceiling.
The rationale is dose accumulation over a year, not toxicity from any one injection in isolation. A patient who needs a fourth or fifth injection into the same joint within twelve months is, in practice, signalling that the underlying pathology needs a different treatment approach rather than another shot.
Hospitals running orthopaedic and pain clinics benefit from logging injection dates per joint per patient in the medical record specifically so this threshold is visible at the point of the next prescribing decision, not reconstructed from memory during a busy outpatient clinic.
What is the infection risk after an intra-articular cortisone injection?
Septic arthritis after intra-articular corticosteroid injection is uncommon: a retrospective analysis of 15,021 injections identified 14 cases within six months, an incidence of 0.093% Septic arthritis following intra-articular corticosteroid injections: a retrospective analysis. Median time to diagnosis was 3.5 weeks post-injection, with presentations clustering between one to three weeks and again at seven to ten weeks.
Staphylococcus aureus and coagulase-negative Staphylococcus species accounted for 42% and 36% of isolated organisms respectively in that cohort, consistent with skin-flora contamination during the procedure rather than a haematogenous source. A separate outbreak investigation traced multiple septic arthritis cases at one outpatient practice directly to breaches in single-dose vial and sterile technique, not to the drug itself Outbreak of Septic Arthritis Associated with Intra-Articular Injections at an Outpatient Practice.
Diabetes, immunosuppression, inflammatory arthritis and BMI above the normal range are the recurring risk factors named across these studies. None of them are reasons to withhold an indicated injection; they are reasons to document technique and flag high-risk patients for closer post-injection follow-up.
Does a cortisone shot raise blood glucose in diabetic patients?
Yes, and the effect is large enough to matter clinically. Intra-articular methylprednisolone acetate (80 mg) produced a peak glucose rise of roughly 3 mmol/l above baseline at 48–72 hours post-injection in diabetic patients monitored continuously, with elevation detectable within the first day and declining over the following two to three days Systemic effects of epidural methylprednisolone injection on glucose tolerance in diabetic patients.
Notably, the same study found the epidural route, at an equivalent 80 mg dose, produced no significant glycaemic change over the two days monitored. Urinary corticosteroid excretion after epidural dosing measured roughly tenfold lower than after intra-articular dosing. That gap is the likely reason the systemic glucose effect differed so much by route. Baseline HbA1c above 7% is associated with a larger-than-expected glucose rise in patients receiving injection, according to related population-based work on glycaemic control after intra-articular steroid use.
A hospital administering an intra-articular cortisone shot to a known diabetic patient has a genuine, evidence-backed reason to counsel that patient to check blood glucose more frequently for two to three days afterward, and to flag the injection date to whoever manages that patient's diabetes therapy that week.
What should a hospital pharmacy get right when stocking cortisone injections?
None of these side effects change without the corticosteroid formulation being handled correctly before it ever reaches the syringe. Methylprednisolone acetate and triamcinolone acetonide, the two most commonly stocked injectable corticosteroids in orthopaedic and pain-management settings, both carry specific temperature and light-protection storage requirements that a pharmacy without a dedicated cold-chain and stock-rotation process can quietly get wrong.
The diabetic blood-glucose counselling point is also, practically, a pharmacy touchpoint and not only a prescribing one. It is the pharmacy team that often hands the patient discharge instructions and is best placed to flag the glucose-monitoring advice at the point of dispensing, not just at the point of injection. A hospital with a managed, in-house pharmacy can build that counselling step into a standard discharge checklist rather than relying on it being remembered case by case, the same discipline that keeps stock rotation and cold-chain handling consistent day to day. Medyzen's guides on managed hospital pharmacy services, pharmacy inventory management for expiry and dead stock, and hospital pharmacy management challenges and best practices cover how formulary discipline and correct storage support this in practice.
Sources
- 1The Use of Steroid Injections for Hand and Wrist Pathologies — PMC, National Institutes of Health
- 2Adverse effects of extra-articular corticosteroid injections: a systematic review — BMC Musculoskeletal Disorders
- 3Cutaneous complications following extra-articular corticosteroid injections: a prospective cohort study — PubMed, National Institutes of Health
- 4Tendon Ruptures Associated With Corticosteroid Therapy — PMC, National Institutes of Health
- 5Septic arthritis following intra-articular corticosteroid injections: a retrospective analysis — Archives of Orthopaedic and Trauma Surgery
- 6Outbreak of Septic Arthritis Associated with Intra-Articular Injections at an Outpatient Practice — New Jersey, 2017 — PMC, National Institutes of Health
- 7Systemic effects of epidural methylprednisolone injection on glucose tolerance in diabetic patients — BMC Research Notes, PMC
This article is for informational purposes and is not a substitute for professional medical advice. Consult a treating physician about corticosteroid injection risks.
FAQ
Frequently asked questions
The most common effects are a transient post-injection flare of pain and swelling, affecting up to 25% of patients in the first 48 hours, and localised skin changes such as depigmentation or fat atrophy near the injection site. Both are more of a counselling issue than a medical emergency in most cases.
Repeated cortisone injections into the same tendon or joint over months to years are linked to tendon weakening, cartilage change, and skin atrophy that can persist for years. A single, appropriately spaced injection carries a far lower long-term risk than a series of closely spaced ones into the same site.
Post-injection flare typically resolves within 48 hours. Skin depigmentation and fat atrophy can take six months to two or three years to fade, and blood glucose elevation in diabetic patients generally returns to baseline within two to three days of the injection.
It can be, but blood glucose rises measurably: around 3 mmol/l above baseline at 48–72 hours after an intra-articular injection in documented studies. Glucose monitoring for a few days afterward is reasonable, particularly for patients with a baseline HbA1c above 7%.
Rheumatology guidance generally caps injections into the same joint at three to four per year, spaced roughly three months apart, based on cumulative cartilage and soft-tissue exposure rather than a single fixed toxicity threshold. Needing more than that in a year usually signals a different treatment is warranted.
Dr. Priya MenonMBBS, MD (General Medicine)
Consultant Physician (Internal Medicine)
Dr. Priya Menon is a consultant physician in internal medicine, writing on drug classes, side-effect profiles, and evidence-based clinical use for hospital and prescriber audiences.