A cortisone injection, which delivers a potent corticosteroid medication, is a common anti-inflammatory treatment used to manage pain in joints, tendons, or bursae. When seeking relief, patients are often surprised and concerned to find their pain temporarily increases instead of decreases immediately following the procedure. This initial worsening of discomfort is a recognized, though not universal, phenomenon that can be attributed to several distinct factors related to both the medication’s composition and the mechanics of the injection itself.
Understanding Post-Injection Flare
The most frequent explanation for worsening pain is a temporary reaction known as a post-injection flare, a localized inflammatory event triggered by the corticosteroid drug itself, distinct from any physical trauma caused by the needle. Many corticosteroid preparations are formulated as a suspension of microcrystals for slow, sustained release. These microscopic crystals can irritate the synovium (the lining of the joint or bursa) before they fully dissolve and begin their anti-inflammatory action. This irritation prompts a brief, localized immune system response, leading to increased pain, warmth, and swelling at the injection site. Symptoms of a flare typically begin within a few hours to 24 hours after the procedure.
Factors Related to the Injection Procedure
Cortisone injections are almost always mixed with a local anesthetic, such as lidocaine, which provides immediate but short-lived numbness and pain relief. The initial relief can lead to a rebound effect when the anesthetic wears off, which usually happens within a few hours. Once the numbing agent dissipates, the patient may feel the original pain return, compounded by minor irritation from the injection process itself.
The physical act of inserting the needle can cause minor trauma, or micro-damage, to the surrounding soft tissues, muscle, or joint capsule, resulting in temporary soreness. For injections into confined spaces like a joint capsule or bursa, the introduction of a fluid volume—comprising both the corticosteroid and the anesthetic—can momentarily increase pressure. This volume effect stretches the surrounding tissues, which can exacerbate existing pain until the fluid is absorbed by the body. These mechanical irritations contribute to the overall feeling of increased pain in the hours immediately following the procedure.
Recognizing Signs of Serious Complication
While a temporary increase in pain is common, certain signs indicate a serious complication requiring immediate medical evaluation. The most concerning risk is a joint infection, known as septic arthritis, which is a rare but severe complication. Signs of infection include rapidly escalating pain that far exceeds the expected flare, significant and spreading redness, pronounced swelling and warmth at the injection site, and systemic symptoms. Systemic signs like fever, chills, or a general feeling of being unwell are red flags that necessitate urgent medical attention.
Another complication is nerve injury, which may manifest as sharp, shooting, or electrical pain that radiates away from the injection site. This type of pain, especially when accompanied by new numbness or muscle weakness, should be reported to a physician promptly.
In extremely rare cases, an allergic reaction to one of the components of the injection can occur. Severe allergic reactions involve symptoms like difficulty breathing, swelling of the face or throat, or a widespread rash. These symptoms constitute a medical emergency.
Expected Recovery Timeline and Self-Care
A post-injection flare is typically short-lived, with symptoms peaking within the first 24 hours and resolving within 48 to 72 hours. Applying ice packs to the injection site for 15 to 20 minutes several times a day can help reduce localized inflammation and swelling. Resting the affected joint is advisable for the first 24 to 48 hours to minimize mechanical stress. Patients should avoid strenuous activities, heavy lifting, or high-impact exercise during this initial recovery phase. The full therapeutic benefit of the corticosteroid usually begins to take effect after the flare subsides, typically within three to seven days of the injection.