The slowly progressive loss of cortisol and aldosterone secretion usually produces a chronic, steadily worsening fatigue, a loss of appetite, and some weight loss. Blood pressure is low and falls further when a person is standing, producing lightheadedness. Nausea, sometimes with vomiting, and diarrhea are common. The muscles are weak and often go into spasm. There are often emotional changes, particularly irritability and depression. Because of salt loss, a craving for salty foods is common. Finally, the increase in ACTH due to the loss of cortisol will usually produce a darkening of the skin that may look like an inappropriate tan on a person who feels very sick. Unfortunately, the slowly progressive chronic symptoms are usually missed or ignored until a sudden event like a flu virus, an accident, or the need for surgery suddenly precipitates a dramatic change for the worse because of the deficient response from the adrenals to one of these stresses. This is referred to as an Addisonian crisis and is a medical emergency.