What are the symptoms of addison's disease other than low cortisol levels?

Severe symptoms: Patients with true addison's disease have severe symptoms that include: orthostatic hypotension (blood pressure drops when standing leading to lightheadedness), loss of appetite (that can be as extreme as nausea/vomiting), weight loss; weakness, fatigue, darkening of the skin. It may present as a chronic illness, suggesting an underlying cancer, as a result, the diagnosis is missed frequently.