Addison's disease (chronic adrenal insufficiency) is a rare and progressive disorder that affects between one and six in every 100,000 people. It affects people of both sexes and
The human body has two adrenal glands, one on top of each kidney. These glands form part of the endocrine system, which works with the nervous system and the immune system to help the body cope with different events and stresses. Addison's disease is caused by the inability of the adrenal glands to make sufficient amounts of regulating hormones.
Adrenaline is the best known of the hormones that are secreted by the adrenal glands in the adrenal medulla (the central part of the gland). The adrenal cortex (the outer part) also produces important hormones, the corticosteroids. They include cortisol, aldosterone and supplementary sex hormones.
In a person with Addison's disease, only the adrenal cortex is affected. The person cannot produce enough glucocorticoid or cortisol and, occasionally, also fails to produce sufficient mineralocorticoid. Levels of aldosterone are nearly always low in people with Addison's disease.