rare disorder defined by destruction of the outer layer of the adrenal glands (adrenal gland), the hormone-producing organs located just above the kidneys (kidney).

The adrenal cortex produces numerous hormones called corticosteroids, which are involved in important functions of the body such as regulation of metabolism, blood pressure, and sodium and potassium levels. Damage to the cortex disrupts the production of two of these hormones, cortisol and aldosterone, leading to a variety of symptoms, including weakness, darkening of the skin and mucous membranes, poor appetite, weight loss, low blood pressure, gastrointestinal upset, and craving for salt or salty foods. Ninety percent of the cortex usually is destroyed before these symptoms become apparent.

In the mid-19th century when the English physician Thomas Addison first described the clinical features of the disease, the destruction of the adrenal cortex was attributed to tuberculosis. Today, worldwide, tuberculosis is still a cause of the disease; in developed countries, however, about 70 percent of cases result from an autoimmune reaction, an inappropriate attack by the immune system (immune system disorder) against, in this case, the adrenal glands. Addison disease also can be caused by fungal infections, cancer, or hemorrhage. Thus, the onset of the disease can be gradual or abrupt.

Replacement therapy (therapeutics) with cortisol (hydrocortisone) and fluorohydrocortisone (as a substitute for aldosterone) will control the symptoms of the disease, but the treatment must be continued throughout life.