Most side effects from a cortisone shot are MILD and short-lived. The common ones are a few days of extra pain at the injection site, a red or flushed face, and a rise in blood sugar if you have diabetes.
The serious ones are rare. The one that needs same-day attention is infection: a joint that gets hotter, redder and more painful after the first couple of days, especially with a fever.
The bigger risks come from REPEATED shots into the same area. That’s why most people are limited to about three a year, spaced at least three months apart.
What’s normal in the first few days
- A pain flare: the area can hurt more for a day or two, sometimes a few days, before it starts to settle. Somewhere between about 1 in 5 and 1 in 3 people notice this. It doesn’t mean the shot has failed
- Numbness then soreness: if a numbing medicine was mixed in, the area may feel great for a few hours, then ache again once it wears off. The steroid itself takes a few days to start working
- A flushed face: warm, red cheeks for a day or several days. It’s harmless and passes on its own
- Bruising or a little swelling where the needle went in
- Trouble sleeping or feeling a bit wired for a night or two. This is less common and settles quickly
For a flare, use ice wrapped in a cloth for 15 to 20 minutes at a time, rest the area for a day or two, and take the painkillers you normally tolerate. See how long a cortisone shot lasts.
If you have diabetes
- Expect your blood sugar to rise: usually in the first one to three days
- Check more often: for about five days after the shot, or longer if your readings stay high
- Have a plan ready: ask your diabetes team beforehand what to do if your numbers climb
- Watch for: strong thirst, passing a lot of urine, or feeling sick and unusually tired. Call your diabetes team if these appear
This matters for shoulder shots in particular, because frozen shoulder is more common in people with diabetes. See frozen shoulder and diabetes.
Skin changes
- Lighter skin: a pale patch around the injection site. It’s more noticeable on darker skin and can be permanent
- Thinner skin or a small dent: the fat under the skin can shrink, leaving a slight dip. This is more likely when the shot is close to the surface, and with repeated shots
- They’re not dangerous, but tell whoever gives your next shot, as it may change where or how they inject
One shot is usually gentle. It’s the third and fourth in the same spot that deserve a harder look.
Why repeated shots are limited
- Tendons can weaken: steroid can soften tendon tissue. Repeated shots near a tendon, such as around the Achilles or the rotator cuff, raise the risk of it tearing. Many doctors avoid injecting right into a tendon for this reason
- Cartilage may thin: in a trial of knee arthritis, shots every three months for two years led to slightly more cartilage loss than salt water, with no better pain relief. See cortisone shot in the knee
- Bone can thin with frequent shots over time
- The usual limit: at least three months between shots, and no more than about three a year in one area. Your doctor may set a different limit. Use theirs
If you need a shot every few months to keep going, that’s a sign to look at the bigger plan: strengthening, load changes, or a surgical opinion. The Cleveland Clinic has a plain summary of the general limits.
Infection: rare but urgent
- It’s uncommon. The skin is cleaned and the needle is sterile
- The timing differs from a flare: a flare peaks in the first day or two and then eases. Infection usually gets WORSE after that, not better
- The signs: the area becomes hot, red, swollen and more painful, often with a fever, chills or feeling generally unwell
Before your next shot
- Tell your doctor about diabetes, blood thinners, any infection or a planned operation. Many surgeons prefer a gap between a joint injection and a joint replacement
- Ask how many you’ve had in that area, and when
- Ask what the plan is if this one wears off
Call your doctor today if
- The area is getting hotter, redder or more swollen after the first two days
- You have a fever or chills, or feel unwell
- Your blood sugar is very high and not coming down, or you feel sick, very thirsty and drowsy
- You feel a sudden snap or pop near the injection site, followed by weakness. This can be a tendon tearing
Get it checked if
- The pain flare lasts longer than about a week
- You notice a dent or pale patch in the skin
- The shot made no difference after two weeks
- You’re being offered shots more often than every three months
A sore few days is normal. Getting worse after that is not.