After a cortisone shot in the shoulder, most people feel numb for a few hours from the local anesthetic mixed into the injection. The pain may then come back, and in some people it flares for 24 to 48 hours before the steroid starts to work. Relief usually begins within 2 to 7 days. When it helps, it often lasts several weeks to a few months. Use that easier window to move and strengthen the shoulder.
A cortisone shot (corticosteroid injection) is commonly used for shoulder bursitis, rotator cuff tendinopathy, frozen shoulder (adhesive capsulitis) and shoulder arthritis. The response varies from months of easier movement to little change.
Key takeaways
- Numbness first: the local anesthetic usually wears off within a few hours.
- Possible short flare: some people have more pain for 24 to 48 hours, which usually settles on its own.
- Relief timing: easing usually starts within 2 to 7 days and, when the shot works, often lasts weeks to a few months.
- Diabetes: blood sugar often runs higher for a few days after the injection.
- Limits: doctors usually cap shots into one shoulder, often at about three or four a year, spaced at least 6 weeks apart.
- The window: the weeks of lower pain are a good time for the exercises that build the shoulder’s tolerance to load.
What the injection is and why it is used
Cortisone is a synthetic version of a hormone your body already makes. Injected into or around the shoulder, it calms inflammation in the tissue it reaches. Common targets are the bursa under the bony tip of the shoulder (subacromial bursa), the main shoulder joint and the small joint at the top of the shoulder (AC joint).
The usual reason for a shot is pain blocking sleep, work or exercise. The steroid does not repair a torn tendon or change the shape of an arthritic joint.
Day by day: the first week
- Day 0, the first few hours: the shoulder may feel numb and easy. As the anesthetic fades, the old pain often returns. Keep the arm moving gently and skip heavy lifting.
- Days 1 to 2: this is when a flare can happen. A “cortisone flare” means more pain than before the shot, thought to come from steroid crystals irritating the tissue. It usually settles within 48 hours. A cold pack for 10 to 15 minutes at a time often helps.
- Days 1 to 5, if you have diabetes: blood sugar often rises within a day of the shot and typically settles within about 3 to 5 days. Check more often than usual.
- Days 3 to 7: the steroid usually starts to take effect. Many doctors advise no heavy lifting, hard overhead work or sport for the first few days to a week. Gentle movement is usually fine.
Weeks 2 to 6
- Weeks 2 to 3: the effect is usually close to its peak. Start or restart your exercise program at a level that leaves the shoulder no worse the next morning.
- Weeks 3 to 6: add a little resistance or a few repetitions each week.
How long the effect lasts, and how to use the window
For most people who respond, relief lasts somewhere between a few weeks and a few months. When it wears off, the pain can return if the tendon or joint still cannot handle everyday load.
That is why the lower-pain weeks matter. Common goals are regaining range, strengthening the rotator cuff and shoulder blade muscles, and changing the loads that set the pain off. Build up slowly: less pain does not mean the tendon is already stronger. A physical therapist can set your starting level and progress it.
The shot turns the pain down. The exercise is what changes how the shoulder copes with load.
How many injections are usually considered
Most doctors limit cortisone shots into one shoulder to about three or four a year, at least 6 weeks apart and often 3 months apart. Repeated steroid near tendons is linked with tendon weakening and with thinning of the skin at the site.
If the first shot did nothing, a repeat of the same shot is less likely to help, and doctors often look again at the diagnosis. If pain returns quickly after each shot, the usual next steps are a structured rehab program, imaging or a surgical opinion.
Is this normal?
- More pain the day after than before: this can be a cortisone flare and usually settles within 48 hours. Pain that keeps rising with heat, redness or fever is different.
- A flushed face or a few poor nights of sleep: common for a day or two and usually harmless.
- Higher blood sugar readings: expected for a few days in people with diabetes. Readings that stay high beyond about 5 days, or go well above your target, need a call to your care team.
- Relief that faded after a few weeks: common. The shoulder may still need time and exercise to build tolerance.
Call your local emergency number or go to the emergency department if
- Signs of a serious allergic reaction: swelling of the face, lips or throat, or trouble breathing after the injection.
- Chest symptoms: chest pain or pressure, breathlessness or sweating along with shoulder or arm pain, especially on the left. These can come from the heart.
See a doctor today if
- Signs of infection: the shoulder becomes hot, red or swollen, or pain keeps rising after the first 48 hours. Infection is rare but needs same-day care.
- Fever: a temperature of 100.4°F (38°C) or higher, or chills, in the days after the shot.
- Severe new pain: pain much worse than anything before the injection that pain relief does not touch.
- Blood sugar out of range: if you have diabetes and readings stay above the range your care team set, or you feel very thirsty, drowsy or unwell.
Get it checked soon if
- No change after 2 weeks: the shot may not have reached the painful tissue, or the pain may come from somewhere else, such as the neck.
- New weakness: difficulty lifting the arm, or a sudden pop followed by loss of strength.
- Tingling down the arm: symptoms past the elbow often point to the neck.
More on this area: injections for neck and shoulder pain.
A cortisone shot buys time. Spend it on movement and strength.
Written by Louise Yow, Neck & Shoulder Physio.