The problem may be due to a disorder of the adrenal glands themselves or inadequate secretion of ACTH by the pituitary gland. Most cases of Addison's disease are caused by the gradual destruction of the adrenal cortex, the outer layer of the adrenal gland, by the body's own immune system. Other less common causes are tuberculosis, chronic infections including fungal infections, cancer cells spreading from other parts of the body, amyloidosis and surgical removal of the adrenal glands. The symptoms usually occur gradually. Chronic, worsening fatigue and muscle weakness, loss of appetite, and weight loss are characteristic of the disease.
Blood pressure falls causing dizziness or fainting.
It can also cause irritability and depression. Left untreated, it can be fatal. A diagnosis of Addison's disease is made by biochemical laboratory tests. The aim of these tests is to determine whether there are insufficient levels of cortisol and then to establish a cause. The ACTH Stimulation test is the most specific tests for diagnosing Addison's disease.