Steroids are potent anti-inflammatory chemical that are normally produced by the body. They are commonly injected in orthopedic conditions. A steroid injection usually contains a mixture of a synthetic steroid and a local anesthetic. There are several types of injectable steroid and they have similar effects but vary in strength, onset, and duration of action. These anti-inflammatory steroids are different from the anabolic steroids that may be abused for body-building and performance enhancement. They also have much less systemic effect than prescription oral steroids which is frequently feared and asked about by patients.
The injection usually take effect within a few days, sometimes up to a week. The benefits can be temporary or last for many weeks. For some conditions, one injection may be enough to completely resolve the problem, while in some cases, repeat injections may be required. If an injection fails to provide complete or satisfactory relief but does show an improvement for a certain period of time, it helps confirm the suspected condition and set the stage for the following step. It also does not burn any bridges. If the suspected condition can be treated with an injection, it is always worth it to try.
There is no set rule as to how many injections a person can get, yet it is popular to limit the number of injections. I usually do not give more than three consecutive injections into the same area in one period. Sometimes, injecting one area can resolve that particular problem but unmask another in a nearby area. This is not uncommon in shoulder problems. Two injections into two different locations of the same joint/area count as individual injections. A common example is a bursa injection and a tendon sheath injection in the same shoulder.
Steroid injections are very safe but, like any other treatment, can have side effects. The most common side effect is a flare reaction. This happens when the steroid crystallizes in the injected area. When this happens, an episode of worsening pain may last one or two days before the injection shows any beneficial effect. Flares resolve spontaneously and can be treated with ice, anti-inflammatories, and immobilization. Flare reactions can be confused with infections. If a flare reaction does not improve after 2-3 days, it should be evaluated on an urgent basis.
Another side effect, especially in patients with darker skin, is skin discoloration at the injection site. The discoloration of the skin can be permanent.
In diabetic patients, a transient increase in blood glucose can happen and usually lasts 5 days. Close monitoring of blood sugar is advisable following a steroid injection.