Addison's disease, also known as primary adrenal insufficiency and hypocortisolism, is a long-term endocrine disorder in which the adrenal glands do not produce enough steroid hormones. Symptoms generally come on slowly and may include abdominal pain, weakness, and weight loss. Darkening of the skin in certain areas may also occur. Under certain circumstances, an adrenal crisis may occur with low blood pressure, vomiting, lower back pain, and loss of consciousness. An adrenal crisis can be triggered by stress, such as from an injury, surgery, or infection. Addison's disease, also known as primary adrenal insufficiency and hypocortisolism, is a long-term endocrine disorder in which the adrenal glands do not produce enough steroid hormones. Symptoms generally come on slowly and may include abdominal pain, weakness, and weight loss. Darkening of the skin in certain areas may also occur. Under certain circumstances, an adrenal crisis may occur with low blood pressure, vomiting, lower back pain, and loss of consciousness. An adrenal crisis can be triggered by stress, such as from an injury, surgery, or infection. Addison's disease arises from problems with the adrenal gland such that not enough of the steroid hormone cortisol and possibly aldosterone are produced, most often due to damage by the body's own immune system in the developed world and tuberculosis in the developing world. Other causes include certain medications, sepsis, and bleeding into both adrenal glands. Secondary adrenal insufficiency is caused by not enough adrenocorticotropic hormone (ACTH) (produced by the pituitary gland) or CRH (produced by the hypothalamus). Despite this distinction, adrenal crises can happen in all forms of adrenal insufficiency. Addison's disease is generally diagnosed by blood tests, urine tests, and medical imaging. Treatment involves replacing the absent hormones. This involves taking a corticosteroid such as hydrocortisone and fludrocortisone. These medications are usually taken by mouth. Lifelong, continuous steroid replacement therapy is required, with regular follow-up treatment and monitoring for other health problems. A high-salt diet may also be useful in some people. If symptoms worsen, an injection of corticosteroid is recommended and people should carry a dose with them. Often, large amounts of intravenous fluids with the sugar dextrose are also required. Without treatment, an adrenal crisis can result in death. Addison's disease affects about 0.9 to 1.4 per 10,000 people in the developed world. It occurs most frequently in middle-aged females. Secondary adrenal insufficiency is more common. Long-term outcomes with treatment are typically good. It is named after Thomas Addison, a graduate of the University of Edinburgh Medical School, who first described the condition in 1855. The adjective 'addisonian' is used to describe features of the condition, as well as people with Addison's disease.