Steroids are powerful and effective drugs used to treat a variety of medical conditions. Corticosteroids, the most common group of steroids, treat arthritis, asthma, autoimmune diseases, skin conditions and some kinds of cancer. A different group of steroids, anabolic steroids, are rarely used in medicine and are more widely associated with performance enhancement and abuse in competitive athletics and weightlifting.

Arthritis and Asthma

One of the main ways steroids work in the body is to reduce inflammation. This is important in conditions like arthritis, where joint inflammation causes pain, swelling and limited mobility. For arthritis, corticosteroids can be taken as a pill, and the medication then spreads throughout the body 1. They can also be injected directly into an inflamed joint, which keeps most of the medication in the area.

Steroids are also effective for asthma. Corticosteroids reduce inflammation and control the body's immune system, which opens the airways inside the lungs 1. Steroids can be given by an inhaler as part of routine care for asthma to reduce symptoms and help prevent acute attacks. For an acute attack that requires a hospital visit, steroids are generally given as an intravenous injection.

Other Conditions -- From Eczema to Cancer

Inflammation is a key component of so many diseases that steroids have seemingly endless medical applications. The list includes certain skin conditions such as eczema, psoriasis and dermatitis, in which steroid creams and ointments may be applied. Oral steroids may be prescribed for autoimmune diseases, such as lupus, Crohn disease and multiple sclerosis. Corticosteroids are also used to treat various eye diseases and some cancers 1. They can help or prevent reduce nausea associated with chemotherapy and decrease some allergic reactions, such as those caused by blood transfusions.

Anabolic Steroids

Anabolic steroids are used legitimately in medicine to treat conditions such as delayed puberty in boys, low testosterone levels and certain bone and blood disorders. Unfortunately, anabolic steroids are used more commonly among weightlifters and other athletes to enhance performance. With the nonmedical use of anabolic steroids comes the potential for abuse, cardiovascular disease and psychiatric disorders.

Side Effects

Steroids have many potential side effects. Take steroids only as prescribed and see your doctor regularly to look for complications. Possible side effects include weight gain, upset stomach, high blood pressure, increased blood sugar and personality changes. Long-term use can lead to brittle bones, glaucoma, cataracts, thin skin, muscle weakness, liver damage and increased susceptibility to infections. Rarely, an allergic reaction may occur, which could appear as a rash, hives or breathing difficulties.

Warnings and Precautions

If you take more than a small dose of corticosteroids every day, your body may not be able to produce the normal amount of natural corticosteroids. This can cause severe problems if you suddenly stop the medication, and it may require an increased dose during times of stress, such as when you have an infection or injury. If you are taking corticosteroids daily, ask your doctor about this possibility. Daily use may also increase your risk of developing severe chicken pox or measles. Contact your doctor immediately if you have been exposed to these viruses.