Corticosteroid injections, sometimes called steroid or cortisone injections, contain synthetic medicines that act like cortisol, a hormone your adrenal glands make naturally. Common preparations include triamcinolone, methylprednisolone and hydrocortisone. They have a powerful anti-inflammatory effect and can be placed into a joint, bursa, tendon sheath or other carefully selected area to reduce pain and swelling. I want to be clear from the outset: a corticosteroid injection can give useful temporary relief, but it does not repair damaged tissue, reverse arthritis or remove the underlying cause of your pain.
A well-targeted steroid injection can calm inflammation and reduce pain relatively quickly, but the benefit is usually temporary. It works best when the diagnosis is clear and the window of relief is used to get on with rehabilitation, not as a treatment on its own.
How do corticosteroid injections work?
Corticosteroids enter cells and bind to glucocorticoid receptors. This changes the activity of genes involved in inflammation and reduces the production of inflammatory substances, including prostaglandins and leukotrienes, interleukins and tumour necrosis factor, chemokines and other signalling proteins, enzymes involved in tissue irritation and breakdown, and the adhesion molecules that help inflammatory cells enter tissues. They also reduce the activity of immune cells and decrease leakage from small blood vessels. Together, these effects can reduce swelling, heat, inflammation and pain.
How quickly does it work, and how long does it last?
The corticosteroid itself is not a local anaesthetic. Pain relief develops as the inflammation, and the sensitivity of local pain receptors, settles down. Improvement commonly begins within a few days, though it can take longer, and occasionally an injection does not give meaningful benefit at all. Some injections also contain a local anaesthetic, which can produce immediate numbness or a few hours of relief; pain may then return as the anaesthetic wears off, before the steroid has started to work.
How long the benefit lasts varies considerably, depending on the condition, how much inflammation is driving the pain, the site and medicine used, the severity of any underlying structural problem, and your individual response. For osteoarthritis, NICE advises being upfront that steroid injections generally give only short-term relief, roughly 2 to 10 weeks. Some people get a longer response, others little or none.
Why is it usually temporary? Because the injection reduces inflammatory activity but does not remove the mechanical, degenerative or biomechanical cause of the pain, so symptoms can return once the medicine has been absorbed. That is exactly why I encourage using the relief to begin or progress rehabilitation, restore movement and strength, modify aggravating activities, and get back to work, exercise and daily life. NICE recommends considering an injection when other medicines are ineffective or unsuitable, or when short-term relief is needed to support therapeutic exercise.
What conditions can be treated?
Corticosteroid injections are commonly considered, in selected cases, for:
- Osteoarthritis
- Inflammatory arthritis or synovitis
- Bursitis
- Frozen shoulder
- Trigger finger
- De Quervain's tenosynovitis
- Carpal tunnel syndrome
- Other painful tendon-sheath or peri-articular conditions
The evidence differs substantially between conditions. A good response in one disorder does not mean a steroid is appropriate for every painful joint or tendon.
A note about tendon problems
Most persistent tendinopathies are not simply inflammatory disorders. A steroid injection may ease pain in the short term in some tendon conditions, but that does not necessarily translate into better long-term recovery. For lateral elbow tendinopathy (tennis elbow), research has found short-term improvement followed by higher recurrence or poorer intermediate-term outcomes in some studies, and a large systematic review in The Lancet found results varied by tendon and were often less favourable beyond the short term.
Steroid should not normally be injected directly into a tendon, because it can weaken the tissue. Particular caution is needed around major load-bearing tendons such as the Achilles and patellar tendons.
Does ultrasound guidance help?
Ultrasound lets me see the joint, bursa, tendon sheath, nerves and blood vessels during the procedure. It can improve the accuracy of needle placement and, importantly, help avoid injecting steroid into a tendon. It is particularly useful when the target is small, deep or hard to identify, when important nerves or blood vessels are nearby, when the anatomy varies, when a previous landmark-guided injection did not work, or when accurate placement into a particular compartment matters. That said, greater technical accuracy does not guarantee better pain relief, whether ultrasound improves the clinical outcome depends on the condition and the site.
Side effects and risks
The injection is placed near the symptomatic area to concentrate treatment there. Even so, some corticosteroid enters the bloodstream and can temporarily affect the rest of the body. Possible short-term effects include pain or swelling after the injection, facial flushing or a feeling of warmth, temporary disturbance of sleep or mood, a rise in blood glucose, bruising or minor bleeding, and changes to the menstrual cycle in some people. These are usually temporary, and whole-body effects are more likely after larger doses, multiple injections or repeated exposure.
Most steroid injections do not cause a serious complication, but no injection is risk-free.
Post-injection flare
Pain can temporarily increase after the injection. This usually settles within a day or two and can often be managed with relative rest, ice and suitable pain relief.
Skin and fat changes
Steroid close to the skin can occasionally cause loss of skin pigment, thinning of the skin, or loss of the fat just under the skin, producing a small dimple. These changes can be long-lasting and are more noticeable in darker skin or at shallow injection sites.
Infection
Infection after an injection is rare but potentially serious. Seek urgent medical advice if the area becomes increasingly hot, red, swollen or painful, particularly if you also feel feverish or unwell.
Tendon injury
Steroid can weaken tendon tissue, particularly if injected directly into a tendon or used repeatedly. Tendon rupture is uncommon but recognised.
Cartilage effects
Repeated or high-dose injections into the same joint may adversely affect cartilage. In a randomised trial published in JAMA, knee injections of triamcinolone every three months for two years produced greater cartilage loss, without better pain control, than saline injections. That finding concerns repeated, scheduled injections, and does not establish that a single injection causes the same effect.
Other uncommon complications
These include bleeding into the injected area, nerve irritation or injury, allergic reaction, and temporary suppression of the body's own steroid production. The risk depends on the medicine, dose, site, how often treatment is repeated, and your other medical conditions.
Diabetes, blood thinners and other precautions
Diabetes. Steroid injections can raise blood glucose, especially if you have diabetes. Glucose should usually be checked more often during the first three days after an injection, with a plan for getting advice if readings become unusually high. If your diabetes is poorly controlled, it is worth discussing the timing and risks with your clinician first (EULAR recommendations).
Blood-thinning medication. Joint and soft-tissue injections are generally considered low-bleeding-risk procedures, but the decision depends on the medicine, dose, site and your individual bleeding risk. Please tell me if you take warfarin, apixaban, rivaroxaban, dabigatran, edoxaban, clopidogrel or another blood thinner. Do not stop prescribed medication unless the clinician responsible for it specifically advises you to.
How many injections can I have?
There is no single safe number that applies to everyone and every body part. Decisions about repeat injections should weigh up how much benefit the last injection gave and how long it lasted, the diagnosis and site, the preparation and dose, previous steroid exposure elsewhere in the body, diabetes and other conditions, and the alternatives. If an injection gave little benefit, simply repeating the same treatment is unlikely to help. Numerous injections into the same area are generally discouraged, because local tissue risks can increase.
After your injection
Unless you are given different instructions, it is usually sensible to:
- Avoid strenuous or heavily repetitive use of the injected area for about 24 hours
- Keep moving gently rather than completely resting the area
- Return to exercise and rehabilitation gradually
- Monitor your blood glucose more closely if you have diabetes
- Follow any specific advice given for a tendon, joint or surgical situation
Contact a healthcare professional promptly if you develop spreading redness, warmth, swelling, severe pain, fever, or you feel generally unwell.
These are not the same as anabolic steroids
Corticosteroids are different from the anabolic steroids sometimes used to build muscle. Corticosteroids act mainly through glucocorticoid receptors and influence inflammation, immunity and metabolism. Anabolic steroids act mainly through androgen receptors and have quite different effects and risks.
The key message
A corticosteroid injection uses a synthetic, cortisol-like medicine to calm inflammatory activity at a carefully chosen site. It can reduce pain and swelling relatively quickly, but the benefit is usually temporary and it does not directly repair damaged tissue. The best results come when the diagnosis is clear, the injection is accurately targeted, and the period of relief is combined with rehabilitation and management of the underlying problem.
Frequently asked questions
Will a steroid injection cure my problem?
How soon does it work, and how long does it last?
Are steroid injections bad for the joint, and how many can I have?
I have diabetes, can I still have one?
Are these the same as the steroids athletes use?
References
- NICE. Osteoarthritis in over 16s: diagnosis and management (NG226), recommendations. 2022.
- Coombes BK, Bisset L, Vicenzino B. Efficacy and safety of corticosteroid injections and other injections for tendinopathy: systematic review and meta-analysis. The Lancet. 2010;376(9754):1751-67.
- McAlindon TE, LaValley MP, Harvey WF, et al. Effect of intra-articular triamcinolone vs saline on knee cartilage volume and pain in knee osteoarthritis: a randomised clinical trial. JAMA. 2017;317(19):1967-75.
- EULAR. Recommendations for intra-articular therapies. 2021.
This page provides general information only. It cannot diagnose your individual problem or replace assessment and advice from a qualified healthcare professional.