The side effects and risks of a cortisone injection include:
- Allergy to any of the substances utilised during the procedure, such as the cortisone, dressing, local anaesthetic or antiseptic. This is usually minor and self limiting.
- The cortisone may result in palpitations, hot flushes, insomnia, and mild mood disturbance. This usually resolves within 24 hours and no treatment is necessary.
- Infection. Infection is a rare but serious complication, especially if injected into a joint. Most infections take at least a day or two to manifest, so pain at the injection site after 48 hours is considered to be due to an infection until proven otherwise. Even if not definitively proven, you may be commenced on empirical antibiotic treatment.
- Local bruising.
- Localised skin and subcutaneous fat atrophy (thinning resulting in dimpling)
- Hypopigmentation (whitening of the skin) at the injection site. This most commonly happens in injections of the palm of the hand or sole of the foot.
- Mild increase in blood sugar levels in diabetic patients for several days and may last up to a week.
- Transient increase in pain at the injection site before the cortisone takes effect. Occasionally this may be severe, however usually lasts only 24–48 hours and is treated with a cold pack, paracetamol and anti-inflammatory medication. If this occurs and you are concerned, especially if the pain is not settling despite the above treatment, then please call contact your referring doctor so that they are able to examine, assess and manage you appropriately.
- Cortisone injection administered directly into a tendon has been reported to weaken and damage the collagen fibers, thus carrying a risk of delayed rupture. For this reason, cortisone is only injected around the tissue surrounding a tendon and the tendon is rested for one week.
- An extremely rare complication is avascular necrosis (bone death) which some doctors suspect may rarely occur when cortisone is injected into a joint, though this has not been proven.