Corticosteroids--potent anti-inflammatory hormones that are made naturally in the body or synthetically (man-made) for use as drugs. They are also called glucocorticoids. The most commonly prescribed drug of this type is prednisone.

Cyclosporine--a strong drug that suppresses the immune system. Originally developed to keep the body's immune system from rejecting transplanted organs, cyclosporine is being used increasingly in autoimmune diseases, including (in rare cases) alopecia areata.

Diabetes--a disease in which the body does not produce or properly use insulin, a hormone that is necessary to convert sugar, starches, and other food into energy.