The symptoms of adrenal insufficiency usually begin gradually. Characteristics of the disease are

• chronic, worsening fatigue
• muscle weakness
• loss of appetite
• weight loss

About 50 percent of the time, one will notice

• nausea
• vomiting
• diarrhea

Other symptoms include

• low blood pressure that falls further when standing, causing dizziness or fainting
• skin changes in Addison's disease, with areas of hyperpigmentation, or dark tanning, covering exposed and nonexposed parts of the body; this darkening of the skin is most visible on scars; skin folds; pressure points such as the elbows, knees, knuckles, and toes; lips; and mucous membranes

Addison's disease can cause irritability and depression. Because of salt loss, a craving for salty foods also is common. Hypoglycemia, or low blood glucose, is more severe in children than in adults. In women, menstrual periods may become irregular or stop.

Because the symptoms progress slowly, they are usually ignored until a stressful event like an illness or an accident causes them to become worse. This is called an addisonian crisis, or acute adrenal insufficiency. In most cases, symptoms are severe enough that patients seek medical treatment before a crisis occurs. However, in about 25 percent of patients, symptoms first appear during an addisonian crisis.

Symptoms of an addisonian crisis include

• sudden penetrating pain in the lower back, abdomen, or legs
• severe vomiting and diarrhea
• dehydration
• low blood pressure
• loss of consciousness

Left untreated, an addisonian crisis can be fatal.