by Carrie MacMillan, Yale University

Credit: Unsplash/CC0 Public Domain

If you're an athlete prone to overuse injuries or if you have a chronic condition like arthritis, chances are you've had a cortisone injection—or at least discussed the treatment with your medical provider.

Cortisone injections are most commonly delivered to joints, including those in the hip, knee, shoulder, spine, or wrist, to tamp down inflammation and pain—with the goal of getting people back to their everyday activities.

"We use cortisone injections to reduce inflammation in any number of settings, though we probably use them for osteoarthritis and tendonitis more than anything else," says Andrea Halim, MD, a Yale Medicine orthopedic surgeon.

Although the name might give it away, many people may not realize that cortisone is a type of corticosteroid, the strongest class of drugs available for reducing inflammation. Corticosteroids can be administered intravenously, orally, topically (as eye drops or skin cream), or by injection.

So, how do you know if a cortisone shot is right for you? How long might relief last? How often can you receive injections? Below, Dr. Halim answers these questions and more.

What are corticosteroids?

Corticosteroids are a group of steroid hormones naturally produced by the adrenal glands. They include cortisone and cortisol (among many other types of hormones), which have anti-inflammatory properties. Synthetic versions of corticosteroids, including hydrocortisone and methylprednisolone, are often used as medications, including as injectables, to reduce inflammation and pain.

What conditions are cortisone shots used to treat?

Cortisone shots can treat a variety of injuries and conditions that cause pain and swelling, including autoimmune diseases, in which the body's immune system mistakenly attacks healthy cells.

Some of the most common conditions treated with cortisone injections include osteoarthritis (when people develop pain and inflammation in their joints), lower back pain (from spinal stenosis or ruptured disks), carpal tunnel syndrome (when nerves in the wrist become compressed or pinched), bursitis (when the fluid sacs that normally act as a cushion between bones, muscles, and skin become inflamed and painful), and tendonitis (when tendons around bones and muscles become inflamed).

It's important to note that cortisone injections are not typically the first line of treatment. Your medical provider may suggest other medications, lifestyle changes, or physical therapy first before addressing pain with a cortisone shot.

How do cortisone shots work?

When cortisone is injected directly into the site of inflammation (often a tendon or joint), the medication suppresses various elements of the immune system, calming inflammation and decreasing pain.

While the injection is useful in reducing pain, it typically doesn't cure the underlying problem that is causing the inflammation, Dr. Halim points out.

"For example, injecting cortisone into an arthritic joint may temporarily ease discomfort related to the joint irritation, but it does not regenerate the patient's damaged cartilage," she says. "In some cases, however, when the problem is caused by a temporary increase in inflammation, a steroid shot can reverse that process and cure the patient's pain. A good example is de Quervain's tenosynovitis [a painful condition in the tendons of the wrist], which is most commonly associated with hormone changes or overuse. A single steroid shot can very commonly resolve the condition permanently."

What is it like to get a cortisone shot?

Cortisone injections are given in your doctor's office and don't require any special preparation. But if you take blood thinners, you might need to stop taking them for a few days before the shot as they can increase bruising and bleeding risks. You should never stop taking blood thinners without the approval of your prescribing physician, adds Dr. Halim.

Your provider will clean the injection site and possibly apply an anesthetic spray to numb the area. Many cortisone injections also include a numbing medication, such as lidocaine, to help make the shot more comfortable.

"How the injection feels depends on where you're getting it. Many injections are not painful or only have a few seconds of discomfort," Dr. Halim says. "However, injections into the sensitive tissues of the palm or the soles of the feet may be more uncomfortable than when they are given into larger joints. The lidocaine kicks in immediately, but the steroid usually takes several days to work."

What are the side effects of cortisone injections?

Allergic reactions are rare, Dr. Halim says. But, as with any treatment, there can be side effects, which for cortisone injections include facial flushing and headaches. There can also be fat necrosis, which is like a divot in the skin, and hypopigmentation [an area of pale skin] at the injection site, Dr. Halim explains.

"You can also get temporary elevations in blood sugar. Typically, that's for about a week," she says.

"There is a risk of injuring a tendon with repeated injections, which is why we are careful about how often we do them," Dr. Halim says. "I space them out at least three months. And if I'm injecting around a tendon, I don't do more than three for any one tendon."

Another possible risk is infection. "This can happen if you don't use a good sterile technique and don't make sure the skin is clean before giving the injection," Dr. Halim says. "It is important to note that if you have surgery on that area too soon after an injection, there is an increased risk of a surgical site infection, because the steroid suppresses the immune system. Most total joint surgeons will not do surgery within two months of a cortisone injection to that joint."

Overall, cortisone injections carry fewer risks than oral steroids, adds Dr. Halim. Those, if used in the long term, can cause osteoporosis, diabetes, and weight gain. "Cortisone injections do not cause the same systemic problems and will not cause weight gain," she says.

Can cortisone injections cure your condition? How long do they last?

In some cases, one or several cortisone shots can cure a condition, particularly those that affect the hand and wrist, Dr. Halim says. "But for conditions that affect the knees, shoulders, and hips, a cortisone injection will make the pain better for a period of time, but is seldom curative," she says.

It's therefore important for patients to ask their doctor how long the injection will offer relief, she adds.

"In terms of how long injections last, I find it varies. For people with trigger finger [when a finger gets stuck in a bent position] or carpal tunnel, it may provide six months of relief," Dr. Halim says. "Some people tell me shots for thumb base arthritis helped for a year, while others say it only helped for two or three weeks. Overall, injections carry a low-risk profile and can be helpful in improving symptoms or at least delaying surgery. And with repeated injections over several years, some people will never need surgery."

How often can you get cortisone injections?

Depending on the condition being treated and where the injection is given, you may receive injections as frequently as every month. For other conditions, doctors may advise that you only receive a few injections within one year.

"Professional athletes sometimes get injections throughout their season, but this should only be done with careful consideration and discussions with an orthopedic sports specialist and an athletic trainer," she says.

But for the weekend warriors or those who want to type, knit, or play a piano pain-free, constant injections are likely not needed.

Provided by Yale University