context: Steroids (short for corticosteroids) are synthetic drugs that closely resemble cortisol, a hormone that your adrenal glands produce naturally. Corticosteroids are different from the male hormone-related steroid compounds that some athletes use. Steroids work by decreasing inflammation and reducing the activity of the immune system. Steroids are used to treat a variety of inflammatory diseases and conditions. Steroid drugs are available in several forms that vary in how easily they dissolve or how long they stay in the body. Steroids may be given systemically, which means throughout the "system" or body, or locally to the precise place where a problem exists. Systemic steroids can be given either through a vein (intravenously, or IV), into a muscle (intramuscularly), or by mouth (orally). Local steroids can be given as eye drops, ear drops, and skin creams, or by direct injection into joints, bursae (lubricating sacs between certain tendons and the bones beneath them), or around tendons and other soft tissue areas. Injecting steroids into one or two local areas of inflammation allows doctors to deliver a high dose of medication directly to the problem area. When doctors give steroids by mouth or intravenously, they cannot be sure an adequate amount of the steroid will eventually reach the problem area. Steroids are often injected directly into joints to treat conditions such as rheumatoid arthritis, gout, or other inflammatory diseases. Steroids also can be injected into inflamed bursae, or around tendons near the shoulder, elbow, hip, knee, hand, or wrist. The decision to prescribe steroids is always made on an individual basis. Your doctor will consider your age, level of physical activity, and other medications you are taking. Your doctor also will make sure you understand the potential benefits and risks of steroid injections. Steroids should not be injected when there is infection in the area to be injected or elsewhere in the body. If a joint is already severely destroyed, injections are not likely to provide any benefit. If a patient has a potential bleeding problem or is taking anticoagulants (often referred to as blood thinners), steroid injections may cause bleeding at the site. For these patients, injections are given only with great caution. Frequent steroid injections, more often than every three or four months, are not recommended because of the increased risk of weakening tissues in the treated area. Local steroid injections are generally well tolerated and are less likely than other forms of steroid medications to produce serious side effects. Before a joint is injected with a steroid, joint fluid may be removed for testing. Testing the joint fluid is especially important if the diagnosis is uncertain. Steroid injections often reduce joint inflammation, helping preserve joint structure and function. Steroid injections may help avoid the need for oral steroids or increased doses of oral steroids, which could have greater side effects. Steroid injections are one of the most effective ways to decrease pain and improve function, yet they generally do not cure the illness. In rare instances, the following side effects might occur: Infection Allergic reactions Local bleeding Rupture of a tendon Skin discoloration Excessively frequent, repeated injections into the same area can cause the bone, ligaments, and tendons to weaken. Not everyone will develop side effects. How often any side effect occurs varies from patient to patient. If steroid injections are infrequent (less than every three to four months), it is possible that none of the listed side effects will occur. Steroid injections can be added to a treatment program that may already include pain medications, anti-inflammatory drugs, physical therapy, occupational therapy, or supportive devices such as canes and braces. Whether one or more of these treatment methods are used depends on the nature of the problem. For example, in an otherwise healthy individual, tendinitis may be adequately treated with only a local steroid injection. However, in a patient with rheumatoid arthritis, injections are generally a small part of a multifaceted treatment approach.