A temporary spike in pain after a cortisone injection is surprisingly common and has a name: a steroid flare. About one in five patients experiences one, and the cause is physical rather than mysterious. Cortisone can crystallize inside the tissue it was injected into, triggering a short-lived inflammatory reaction that feels like the original problem just got worse. The flare almost always resolves on its own within a few days, but it is not the only reason you might hurt more after the shot, and a few warning signs deserve prompt medical attention.
What Causes a Steroid Flare
Cortisone is delivered as a suspension of tiny particles. Once those particles are deposited in a joint or soft-tissue space, some of them can form needle-shaped crystals. Research has shown that cortisone crystallizes when it interacts with lipid membranes at high local concentrations, and those crystals irritate the surrounding tissue the same way gout crystals do, provoking a burst of inflammation right at the injection site.1PubMed Central. The Lipid Bilayer Provides a Site for Cortisone Crystallization at High Cortisone Concentrations The result is swelling, warmth, and pain that can feel as bad as, or worse than, whatever brought you to the doctor in the first place.
The flare is a reaction to the physical form of the drug, not to an allergic response or to damage caused by the needle. Once the crystals dissolve and the steroid begins suppressing inflammation as intended, the pain subsides and the therapeutic effect takes over. That transition usually happens within 24 to 72 hours, though some people feel the flare for up to five days.
How Common Flares Are and Who Is More Likely to Get One
A prospective study that tracked 140 patients after musculoskeletal corticosteroid injections found that roughly 21 percent reported a flare of pain afterward.2PubMed Central. Prospective Evaluation of Pain Flares and Time Until Pain Relief Following Musculoskeletal Corticosteroid Injections That is not a rare side effect. If five people get injections in the same clinic on the same day, statistically at least one of them walks out of the building and has a rougher night than expected.
The same study found that younger age was the only significant predictor of getting a flare, with roughly a 5.5 percent decrease in the odds of a flare for every additional year of age. Gender, body mass index, where the injection was given, how much pain the patient had beforehand, and the specific type of corticosteroid used made no measurable difference.2PubMed Central. Prospective Evaluation of Pain Flares and Time Until Pain Relief Following Musculoskeletal Corticosteroid Injections That last finding is worth noting because patients sometimes assume that switching to a different steroid formulation will prevent a flare. The evidence so far does not support that assumption.
Why younger patients are more prone is not entirely clear. One plausible explanation is that a younger, more robust immune system mounts a stronger inflammatory response to the crystal irritant, but this has not been confirmed. Whatever the reason, if you are relatively young and had a flare once, you may be more likely to get one again with a future injection.
What Actually Helps During a Flare
The standard advice after a cortisone shot is to rest the area, take an over-the-counter pain reliever like ibuprofen or acetaminophen, and ice the injection site. The icing part, though, may not do much. A randomized controlled trial in hand and wrist injection patients compared scheduled analgesics plus ice against analgesics alone and found no significant difference in pain scores at any point from one to five days post-injection.3PubMed. Effect of ice on pain after corticosteroid injection in the hand and wrist: a randomized controlled trial Nearly half the patients in the ice group still had pain spikes of at least two points on a ten-point scale, which was actually a slightly higher rate than in the group that skipped the ice. That does not mean ice is harmful, but it probably should not be your main strategy.
Over-the-counter anti-inflammatory drugs remain the most practical option. The flare is an inflammatory event, so an NSAID addresses it directly. If you cannot take NSAIDs for medical reasons, acetaminophen and rest are reasonable stand-ins. Most flares peak within the first day or two and taper from there. If pain is still climbing on day three or four rather than leveling off, that timeline is unusual enough to justify a call to your doctor.
When the Pain Is Not a Flare
A steroid flare is uncomfortable but harmless. A few other post-injection problems are not, and telling them apart matters. The key distinction is trajectory and associated symptoms.
- Infection: Joint infection after a corticosteroid injection is rare, but when it occurs it tends to be serious. A retrospective study over 17 years found that septic arthritis following injections most often involved the knee, and the most common culprit was Staphylococcus aureus.4PubMed Central. Septic arthritis following joint injections: a 17 years retrospective study in an Academic General Hospital Nearly half of those patients had a history of multiple injections. The hallmark difference from a flare is that infection typically gets steadily worse rather than peaking and fading, and it tends to come with fever, severe redness, and an inability to move the joint at all. If you have those symptoms, seek care immediately.
- Tendon damage: Corticosteroid injections near tendons carry a small risk of weakening or rupturing the tendon. A systematic review of extra-articular injection side effects documented tendon ruptures, along with plantar fat atrophy after injections near neuromas.5PubMed Central. Adverse effects of extra-articular corticosteroid injections: a systematic review Tendon-related pain typically feels sharp and specific, and you may notice sudden weakness in the affected muscle.
- Skin and tissue changes: Corticosteroids can cause localized skin thinning, lightening of skin color, or small depressions at the injection site. These changes are more cosmetic than painful, but they can be alarming if nobody warned you about them.
The practical rule is simple: a flare behaves like a wave that crests and falls within a few days. Anything that keeps climbing in intensity, brings a fever, or causes new mechanical symptoms like sudden weakness is not a flare and needs medical evaluation.
Systemic Side Effects You Might Mistake for Worsening Pain
Cortisone does not stay entirely local. Some of it enters your bloodstream, and the systemic effects can be surprisingly common. A retrospective cohort study of over a thousand patients who received guided corticosteroid injections found that about a third reported at least one systemic side effect.6American Journal of Physical Medicine & Rehabilitation. Incidence and Risk Factors of Systemic Adverse Effects and Complications of Ultrasound- and Fluoroscopy-Guided Glucocorticoid Injections: A Retrospective Cohort Study The most frequent effects were facial or body flushing (about 13 percent of patients), blood sugar elevation (about 7 percent), and a rise in systolic blood pressure (roughly 5 percent). Flushing was far more common in women, affecting roughly 19 percent of female patients versus 4 percent of males.
The blood sugar spike deserves special attention if you have diabetes. In the same study, nearly 30 percent of diabetic participants experienced hyperglycemia after the injection, compared with less than 1 percent of non-diabetic participants.6American Journal of Physical Medicine & Rehabilitation. Incidence and Risk Factors of Systemic Adverse Effects and Complications of Ultrasound- and Fluoroscopy-Guided Glucocorticoid Injections: A Retrospective Cohort Study That spike tends to start around day two after the procedure. If you manage your blood sugar closely, you and your doctor should plan for it in advance and possibly adjust your medication temporarily.
Other systemic effects included insomnia, restlessness, and in rare cases hallucinations. The flushing and restlessness typically started the day after the injection, while blood pressure and blood sugar changes took about two days to peak. None of these are “pain getting worse” in the strict sense, but they can make you feel terrible in ways that combine with the local flare to create an overall sense that the injection made everything worse.
What Repeated Injections Do to Cartilage
If you have had multiple cortisone injections and feel like each one helps less than the last, the cartilage research offers a possible explanation. A systematic review of corticosteroid effects on articular cartilage found that the relationship between dose and cartilage health follows a clear pattern: low doses tended to promote cell growth and recovery, while higher doses were associated with significant cartilage damage and cell death.7PubMed Central. The Effect of Intra-articular Corticosteroids on Articular Cartilage The threshold in animal models sat at around two to three milligrams per individual dose; above that, and especially as cumulative doses climbed, cartilage health declined.
This is part of why doctors generally limit the number of cortisone injections you can receive in a single joint per year. A meta-analysis also noted that patients who received repeated steroid injections had worse pain scores at six and nine months compared to control groups, though the authors pointed out that steroid pain relief is inherently transient and would not be expected to last that long regardless.8PubMed Central. Evidence suggests that intraarticular corticosteroids are effective (short term) and safe (long term) In other words, the injections wear off, and if the underlying disease is progressing, you can end up in more pain than you started with, even though the injection itself did its short-term job.
Research on tendons tells a related story. In an animal study of injured rotator cuff tissue, corticosteroid treatment triggered a greater than fourfold increase in the ratio of type-III to type-I collagen, which is a shift toward weaker, less organized connective tissue.9PubMed Central. The Effect of Corticosteroid on Collagen Expression in Injured Rotator Cuff Tendon The ratio returned to normal by three weeks, suggesting the effect is temporary, but it raises questions about what happens in tendons that are repeatedly exposed to corticosteroids before they fully recover.
The Numbing Agent Might Be Part of the Problem
Cortisone injections almost always include a local anesthetic, usually lidocaine or bupivacaine, to numb the area and make the shot itself less painful. That painkiller wears off within hours, and the contrast between a numb joint and a newly inflamed one can make the flare feel dramatically worse than it would otherwise. But beyond the perception issue, there is growing evidence that the anesthetic itself may not be harmless to the joint.
A systematic review of local anesthetic effects on human knee cartilage found that lidocaine, bupivacaine, ropivacaine, levobupivacaine, and mepivacaine all had dose- and time-dependent toxic effects on cartilage cells, and that those effects were made worse when corticosteroids were co-administered.10PubMed. Chondrotoxic Effects of Local Anesthetics on Human Knee Articular Cartilage: A Systematic Review Laboratory research comparing specific agents confirmed that lidocaine and bupivacaine caused visible damage to cell structures and significantly reduced the number of living cartilage cells, while ropivacaine appeared to be somewhat less harmful.11PubMed Central. Local Anesthetics’ Toxicity toward Human Cultured Chondrocytes: A Comparative Study between Lidocaine, Bupivacaine, and Ropivacaine A broader scoping review reached a similar conclusion, noting that ropivacaine and liposomal bupivacaine appeared to be safer options.12PubMed Central. Chondrotoxicity of Intra-Articular Injection Treatment: A Scoping Review
This does not mean you should refuse the numbing agent. The cartilage damage documented in these studies occurred under controlled lab conditions and with direct, sustained exposure. A single clinical injection delivers a brief burst of anesthetic that is absorbed and cleared relatively quickly. Still, the finding adds nuance to the conversation about repeat injections: it is not just the steroid that accumulates effects on the joint over time, but potentially the anesthetic paired with it.
Alternatives When Cortisone Stops Making Sense
Cortisone injections are generally considered a short-term tool. Guidelines from the American Society of Regional Anesthesia and Pain Medicine note that the pain relief from intra-articular corticosteroid injections lasts anywhere from a few weeks to a few months.13BMJ Journals. Use and safety of corticosteroid injections in joints and musculoskeletal soft tissue: guidelines from the American Society of Regional Anesthesia and Pain Medicine When that window keeps shrinking with each injection, or when the flares and side effects start outweighing the temporary relief, it is worth discussing other options.
Hyaluronic acid injections work differently. Rather than suppressing inflammation, they aim to supplement the joint’s natural lubricant. Evidence suggests they may reduce pain in mild knee osteoarthritis for up to about six months.14PubMed Central. Intraarticular injections (corticosteroid, hyaluronic acid, platelet rich plasma) for the knee osteoarthritis Platelet-rich plasma, or PRP, uses concentrated growth factors from your own blood and has shown promise for pain relief and improved function, particularly in younger patients with milder disease. The evidence base for PRP is still developing, but early results have been encouraging enough that many orthopedic practices now offer it alongside or instead of cortisone.
Physical therapy, weight management, bracing, and activity modification remain the foundation of joint care. Injections of any type sit on top of that foundation, not in place of it. If cortisone flares are a recurring problem for you, it is worth having a broader conversation with your provider about whether the injection is still serving you or whether the joint has moved past the point where a steroid can meaningfully help.
Why the Flare Can Feel So Disproportionate
There is a psychological dimension worth acknowledging. You went to the doctor because you were in pain. You agreed to a needle in your joint. You expected relief. Instead, you got worse pain. That gap between expectation and reality can amplify how bad the flare feels, independent of the actual inflammation. Interestingly, a controlled study on whether giving patients detailed information about epidural steroid injections ahead of time would reduce their anxiety and post-procedure pain found that it made no measurable difference.15PubMed. Do informative leaflets affect pre-procedural anxiety and immediate pain after transforaminal epidural steroid injections? A prospective randomized controlled study Knowing a flare might happen does not appear to blunt the experience of it.
That said, knowing what is happening and why it is happening can at least spare you the worry that something has gone wrong. A steroid flare is the most common explanation for post-injection pain, it follows a predictable timeline, and it resolves on its own. The real value of understanding the flare is not that you will feel it less, but that you will not spend those two or three days convinced the injection damaged your joint or that you need to rush to the emergency room. Save your concern for the warning signs that genuinely warrant it: fever, worsening redness, progressive swelling that does not plateau, or new mechanical symptoms like buckling or sudden weakness.