Getting a corticosteroid injection

Local steroid injections can be used quickly and effectively to treat symptoms of pain and inflammation in or around joints, tendons and soft tissue. Many people receive these injections daily across the UK with good results, but it is important to appreciate that its effects are temporary, it has its limitations and, as with all drugs, some people can have side effects.

If you have been recommended a steroid injection and want to find out more read on.

What is a cortisone injection?

Corticosteroids, commonly referred to as cortisone, are man-made drugs similar to a naturally occurring hormone we make in our adrenal glands. This group of steroids is different to the anabolic steroids commonly associated with athletic performance or bodybuilding.

Corticosteroids work by decreasing inflammation and, if used in appropriate doses, can reduce the activity of the immune system which is why it is commonly used to treat conditions like rheumatoid arthritis, asthma and eczema, to name a few.

They can be given as an oral medication, an inhaler (asthma treatment), a nasal spray, such as for hay fever, or a topical cream.

Why inject a corticosteroid?

Administering a cortisone injection into an area of inflammation allows direct delivery of the drug to the problem area. It ensures the majority of the medication reaches the area of concern and reduces the likelihood of systemic effects, which is not the case if you take it by mouth or into a vein (intravenous).

Common musculoskeletal reasons for getting a steroid injection include:

• Joint injection - pain relief from arthritis symptoms.
• Peritendinous injection - to address inflammation inside or around a tendon (e.g. trigger finger).
• Perineural injections - to reduce the inflammation and sensitivity of painful nerves e.g. carpal tunnel syndrome.
• Intramuscular injection - injection into a muscle to address pain in another unreachable part of the body e.g. back pain.
• Bursa injection - to treat bursitis and reduce the chances of recurrence.

What are the side effects of a cortisone injection?

Side effects of a steroid injection depend on which drug is used, the composition, how much is given and to which body part. In most cases, no side-effect is experienced apart from bruising at the site of the injection. Other possible side effects include:

Allergic reaction - Although it is very rare you can develop an allergic reaction to any of the constituents of a steroid injection. This is ironic given that one treatment for an allergic reaction is corticosteroid medication.

Infection - A rare but noteworthy complication occurring in roughly 1:10000. If the area remains painful beyond the first 2 days (the window for an expected steroid flare), becomes red, hot, swollen or you feel unwell see your doctor urgently.

Worsening pain at the injection site  - a steroid flare affects about 20% of patients within the first 24 - 48 hours of injection and can last for 2 days. Apply ice over the area and take over-the-counter pain medication to counter.

Skin changes - Steroids can cause thinning, itchiness, dryness and loss of contour due to fat atrophy. 1.3 - 4% will develop temporary skin discolouration (hypopigmentation) anywhere up to 4 months after injection and this can last up to 3 years. This is particularly common when stronger steroid preparations are injected close to the surface of the skin.

Rise in blood sugar - If you have diabetes you can still have a steroid injection but you should monitor your blood sugar level closely over the next couple of days and adjust your medication accordingly. Speak to your doctor if you have any concerns.

Raised blood pressure - This is more common if you already have raised blood pressure. If you have hypertension monitor your blood pressure over the next couple of days after getting a cortisone shot and if you have any concerns contact your GP.

Facial flushing - More likely to be experienced by females, facial flushes can start soon after a steroid injection and usually stop spontaneously after a couple of days.

Changes to your period - Your menstrual cycle can be temporarily disrupted but is normally back to normal by the next cycle. A corticosteroid injection can also cause post-menopausal bleeding so don't be alarmed if this happens. If you get bleeding that is heavy or fails to stop 2 weeks after injection, arrange to see your doctor.

Tendon rupture - Cortisone injections can weaken tendons putting them at risk of rupture. This is one reason why we may limit the number of injections you can have to one area.

Most side effects occur rarely and when they do tend to be mild. Your doctor will have weighed up the benefits of having an injection over the risks before recommending it. If you have any concerns, before or after injection, speak to your doctor.

Preparing for your corticosteroid injection

If you are on blood thinners you will need to stop taking them for a couple of days before your cortisone shot to reduce your risk of bleeding or bruising. Check with your GP or specialist beforehand to make sure it is safe to do so. 

Some dietary supplements also have a blood-thinning effect. Ask your doctor what medications and supplements you should avoid before your cortisone injection.

Tell your doctor if you have had a temperature in the week before your procedure.

Arrange to have your steroid injection at least 2 weeks before, or delay it for more than 2 weeks, after any vaccination.

Ideally, come with someone who can take you home or give you moral support.

You will be asked to expose the problem area so, dress appropriately.

What should I expect after a cortisone shot?

After your cortisone injection, you should:

• Protect the injected area for a day or two: for instance, if you received a shot in your shoulder, avoid heavy lifting. If you received a shot in your knee, try to avoid excessive walking for 48 hours.
• Apply ice to the site as needed to relieve pain. Do not use heat pads.
• Don't use a bathtub or hot tub for two days. It's OK to shower.
• Watch for signs of infection, including increasing pain, redness and swelling that lasts beyond the first 48 hours.
• Ideally, avoid driving on the day of your injection. If you are involved in an accident, even if you are not at fault, the onus will be on you to prove that you had control of the vehicle at the time.

When should you not get a steroid injection?

• If there is an infection in the area to be injected or you have an active infection elsewhere in the body. This includes if you are currently unwell with a systemic illness like a cold or flu.
• If there is broken skin over the site to be injected.
• If you are within 2 weeks of having a vaccination.
• If the joint to be injected has a prosthesis (e.g. total knee replacement).
• If you have a fracture/broken bone at the site of the injection.
• If you've had several injections with short-lived improvement.
• Having a tendency to bleed or taking blood thinners does not stop you from having an injection but you must make your doctor aware of this beforehand as it will affect how you get treated.

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