Prednisone is a corticosteroid (cortisone-like medicine or steroid). It works on the immune system to help relieve swelling, redness, itching, and allergic reactions. This medicine is available only with your doctor's prescription. Learn about the side effects of prednisone, from common to rare, for consumers and healthcare professionals. Overview: Prednisone is used to treat a variety of inflammatory, autoimmune, and hormonal conditions. It works by suppressing the body’s immune response and reducing inflammation. Common side. Prednisone is a prescription medicine used to treat acute asthma, arthritis, allergic reactions, respiratory illness, and many other conditions. Learn about dosage, side effects, warnings, and more. Prednisone is a glucocorticoid medication mostly used to suppress the immune system and decrease inflammation in conditions such as asthma, COPD, and rheumatologic diseases. [3] Corticosteroid medicines include cortisone, hydrocortisone and prednisone, among others. They help treat rashes, inflammatory bowel disease, asthma and several other conditions. But corticosteroids also may have serious side effects. Prednisone is used to treat allergic disorders, ulcerative colitis, psoriasis and arthritis. Learn about side effects, interactions and indications. Prednisone is in a class of medications called corticosteroids. It works to treat patients with low levels of corticosteroids by replacing steroids that are normally produced naturally by the body. Prednisone is a steroid medication that treats a wide range of health conditions including asthma, allergic reactions, arthritis and inflammatory bowel disease.