- Autoimmune damage: The most common cause of Addison's disease in the United States; the immune system attacks the adrenal cortex. It often occurs alongside other autoimmune conditions such as thyroid disease (hypothyroidism) and type 1 diabetes.
- Stopping long-term steroid therapy: The most common cause overall. Prolonged prednisone or other glucocorticoid treatment suppresses the body's own cortisol production, which needs time to recover after tapering.
- Pituitary disease: Tumors, surgery, or radiation affecting the pituitary reduce the signal (ACTH) that drives cortisol production.
- Other causes: Infections, bleeding into the glands, and certain cancers or medications can damage adrenal tissue.
- Profound fatigue and weakness: The most consistent feature.
- Weight loss and poor appetite: Often with nausea or abdominal discomfort.
- Low blood pressure and dizziness on standing: Especially when aldosterone is deficient.
- Salt craving: A classic clue in primary adrenal insufficiency.
- Darkening of the skin: Bronzing of skin creases, scars, and gums occurs in Addison's disease.
- Low blood sugar and low mood: Cortisol helps maintain both.
- Muscle and joint aches: Diffuse soreness without swelling is common and often mistaken for overexertion or arthritis.
- Loss of body hair and reduced libido: More noticeable in women, who depend on the adrenal glands for a share of their androgen production.
- Glucocorticoid replacement: Hydrocortisone taken in divided daily doses, or sometimes prednisone once daily, replaces cortisol.
- Mineralocorticoid replacement: Fludrocortisone replaces aldosterone in primary adrenal insufficiency, maintaining blood pressure and salt balance.
- Sick-day rules: Doses must be increased during fever, significant illness, or surgery, because the body cannot raise cortisol on its own. Patients should carry a steroid emergency card and wear medical identification.
- Hydration and heat awareness: Florida heat increases salt and fluid losses, so staying hydrated matters, particularly with aldosterone deficiency.
- Adrenal crisis: A sudden, dangerous shortfall of cortisol triggered by infection, injury, surgery, vomiting, or missed doses — the most serious complication and the reason sick-day education is emphasized at every visit.
- Low sodium and dehydration: Without enough aldosterone, salt and water are lost in the urine, producing weakness, lightheadedness, and low blood pressure.
- Associated autoimmune disease: Addison's disease frequently occurs alongside autoimmune thyroid disease, type 1 diabetes, and vitamin B12 deficiency, so periodic screening is part of long-term follow-up.
- Effects of imperfect replacement: Too little cortisol leaves persistent fatigue and low blood pressure, while consistently high doses over years contribute to weight gain, higher blood sugar, and bone loss (osteoporosis) — which is why doses are reviewed and adjusted rather than set once and forgotten.