Are steroid injections safe?
Corticosteroid injections — commonly called cortisone injections or steroid injections — are a well-established and generally very safe treatment for musculoskeletal pain. They have been used in clinical practice for decades and, when performed correctly by an experienced clinician, the risk of significant side effects is low.
That said, it is important to be aware of what to expect after an injection, and to know when symptoms are normal versus when you should seek advice.
Common side effects of steroid injections
Steroid flare
A steroid flare is a temporary worsening of pain in the injected area, usually beginning within 24 hours of the injection and lasting 24–72 hours. It is thought to be caused by the crystalline form of the steroid triggering a brief inflammatory response.
Around 2–10% of patients experience a steroid flare. It is self-limiting and can usually be managed with ice, and rest. If it persists beyond 72 hours or is accompanied by redness, warmth, or fever, contact your clinic, as this could indicate infection.
Temporary pain increase
Some patients notice that the injection does not provide immediate relief and that pain levels are unchanged — or slightly higher — for the first few days. This is normal. Most patients begin to notice improvement at three to five days.
Skin changes
Repeated steroid injections into superficial areas (such as tendons or near the skin surface) can occasionally cause:
- Skin thinning (atrophy) at the injection site
- Depigmentation — a pale patch of skin
- Subcutaneous fat atrophy — a small dimpling or indentation under the skin
These changes are more likely with frequent injections into the same area, or when the steroid is inadvertently deposited too superficially. At Alton Pain Clinic, ultrasound guidance is used on every injection to ensure accurate placement, which significantly reduces this risk.
Facial flushing
Some patients experience temporary facial flushing or redness in the hours following an injection. This is a benign systemic reaction to the steroid and typically resolves within 24–48 hours. To learn more about this, read our blog here.
Temporary rise in blood sugar
Corticosteroids can cause a transient rise in blood glucose. For most patients, this is not clinically significant. However, if you have diabetes, you should monitor your blood sugar more closely in the days following an injection and discuss this with your clinician.
Less common side effects
Tendon weakening
Corticosteroids can cause a transient rise in blood glucose. For most patients, this is not clinically significant. However, if you have diabetes, you should monitor your blood sugar more closely in the days following an injection and discuss this with your clinician.
Infection
Infection following a steroid injection is rare (estimated at less than 1 in 10,000 procedures) but is a serious complication. Signs of infection include increasing redness, warmth, swelling, and pain in the days following the injection, often with fever. If you experience these symptoms, seek medical attention promptly.
Menstrual irregularity
Some women notice a disruption to their menstrual cycle following a steroid injection. This is usually a single-cycle irregularity and resolves spontaneously.
How many steroid injections are safe?
Current guidance recommends a maximum of three steroid injections per site per year, with at least six to eight weeks between injections. Exceeding this frequency increases the risk of tissue damage and systemic side effects. To learn more about this, read our blog here.
Your consultant at Alton Pain Clinic will always advise you on the appropriate frequency for your individual situation, and will discuss alternative treatments — such as hyaluronic acid or PRP — if further steroid injections are not recommended.
This article is intended for informational purposes only and should not replace professional medical advice. If you are experiencing persistent symptoms, please consult a qualified clinician.
Frequently Asked Questions
How long do steroid injection side effects last?
Most side effects — including steroid flare, facial flushing, and mild pain increase — resolve within 48–72 hours. Skin changes from repeated injections may be longer lasting. Systemic effects such as blood sugar elevation typically normalise within a few days.
What should I do if I have a steroid flare?
Apply ice to the area for 15–20 minutes several times a day. If symptoms do not improve within 72 hours, or if you develop fever or increasing redness, contact the clinic
Can I have a steroid injection if I am diabetic?
Yes, but with caution. Steroids can cause a temporary rise in blood sugar, which may last several days. If you have diabetes, particularly if it is not well controlled, discuss this with your consultant. You should monitor your blood glucose more closely in the days following the injection.
Do steroid injections weaken the immune system?
A single local steroid injection has a minimal effect on the immune system. However, patients who are significantly immunocompromised (for example, those on high-dose immunosuppressants or chemotherapy) should discuss the timing of injections with their clinician.