Addison's disease is a hormone deficiency (not enough hormone) caused by damage to the outer layer of the adrenal gland (the part known as the adrenal cortex).

The adrenal glands are small hormone-secreting organs located on top of each kidney. They consist of the outer portion (called the cortex) and the inner portion (called the medulla). The cortex produces 3 types of hormones: glucocorticoid hormones, mineralocorticoid hormones, and sex hormones.

• The glucocorticoid hormones (such as cortisol) maintain glucose (sugar) control, suppress (decrease) immune response, and help the body respond to stress.
• The mineralocorticoid hormones (such as aldosterone) regulate sodium and potassium balance.
• The sex hormones, androgens (male) and estrogens (female) affect sexual development and reproduction.

Addison's disease results from damage to the adrenal cortex. The damage causes decreased production of the hormones produced by the cortex. This damage may be caused by the following:

• The immune system mistakenly attacking the gland (autoimmune disease)
• Infections such as tuberculosis, HIV, or fungal infections
• Hemorrhage, blood loss
• Tumors
• Use of blood-thinning drugs (anticoagulants)

Risk factors for the autoimmune type of Addison's disease include other autoimmune diseases:

• Type I diabetes
• Hypoparathyroidism
• Hypopituitarism
• Pernicious anemia
• Testicular dysfunction
• Graves' disease
• Chronic thyroiditis
• Dermatis herpetiformis
• Vitiligo
• Myasthenia gravis

These may be caused by certain genetic defects.

• Extreme weakness
• Fatigue
• Unintentional weight loss
• Nausea and vomiting
• Chronic diarrhea
• Loss of appetite
• Darkening of the skin - patchy skin color
  • Unnaturally dark color in some locations
  • Paleness may also occur
• Mouth lesions on the inside of a cheek (buccal mucosa) - pigmentation
• Slow, sluggish movement
• Changes in blood pressure or heart rate
• Salt craving

• Blood pressure is low.
• Cortisol level is low.
• Serum sodium is low.
• A potassium test may show increased potassium.
• An abdominal x-ray may show adrenal calcification.
• An abdominal CT scan may show adrenal calcification, enlargement or atrophy.
• Sex hormone levels will probably remain normal, because these hormones are also made by the ovaries or testes (and in larger amounts).

• Renin
• Potassium test
• Cortisol, urine
• CO2
• Aldosterone
• ACTH
• 24 hour urinary aldosterone excretion rate
• 17-ketosteroids
• 17-hydroxycorticosteroids
• Cortrosyn stimulation test (Cortrosyn is a man-made form of part of the ACTH hormone)
• Blood eosinophil count (a special white blood cell)