Addison's Disease — or primary adrenal insufficiency — occurs when the adrenal glands fail to produce adequate levels of cortisol and aldosterone. These hormones regulate metabolism, blood pressure, immune function, and the body's response to stress.
In most cases the cause is autoimmune: the immune system mistakenly attacks and destroys adrenal tissue. Diagnosis is often delayed by years because the symptoms — fatigue, weight loss, low blood pressure, skin darkening — overlap with dozens of other conditions.
There is no cure. Those diagnosed manage the disease through daily hormone replacement therapy and constant vigilance against adrenal crisis, a life-threatening emergency that can be triggered by illness, injury, or stress.