Causes
The causes differ by type:- 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.
Symptoms
Symptoms build gradually and are easy to attribute to other things:- 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.
Diagnosis
Diagnosis rests on demonstrating low cortisol. An early-morning cortisol level is a common first step, and an ACTH stimulation test — measuring the adrenal response to a synthetic pituitary signal — confirms the diagnosis. The ACTH level itself distinguishes primary from secondary disease, and blood tests may show low sodium and high potassium in Addison's disease. Adrenal antibodies or imaging identify the underlying cause. Timing matters, because cortisol is naturally highest in the morning and lowest at night; a level drawn in the afternoon can be misleading. It is equally important to tell your physician about any recent steroid use — including inhaled, injected, and topical preparations, which are easy to forget — since these both suppress the body's own production and interfere with test results. When symptoms are strongly suggestive and the patient is unwell, treatment is started before testing is complete rather than delayed.Treatment
Treatment replaces the missing hormones and prepares patients for stress:- 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.
Complications
Most problems arise when replacement is interrupted, or when doses are not increased at the moments the body most needs cortisol:- 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.
When to Seek Immediate Care
Adrenal crisis — severe vomiting, dehydration, confusion, or collapse with very low blood pressure — is life-threatening and requires emergency treatment with injectable hydrocortisone and IV fluids. Call 911 if these symptoms occur. With daily replacement therapy and good sick-day education, people with adrenal insufficiency live full, active lives. The internal-medicine team at Zimmer Medical Group coordinates testing, treatment, and endocrinology care for adrenal disorders.Living Safely With Adrenal Insufficiency
Once diagnosed, adrenal insufficiency is managed with a few tablets a day, and nearly every serious problem comes from the days when those tablets are not enough. The habits below are what separate an uneventful life from a hospital admission.
Taking hydrocortisone the way the body would make it
Hydrocortisone is split so that the largest dose is taken on waking and the last no later than mid-afternoon, mimicking the natural rhythm and protecting sleep. Prednisone once each morning is an alternative when a single daily dose is easier to keep to. Doses are set by symptoms and blood pressure rather than by a blood test, and persistent tiredness on a stable dose is more often untreated hypothyroidism or poor sleep than a need for more cortisol.
Sick-day rules that actually get used
The daily dose is doubled or tripled during any fever, significant infection, or injury, and returned to normal a day or two after recovery. Vomiting that prevents tablets from staying down is the signal for the injection: every patient keeps an emergency hydrocortisone injection kit at home and in travel luggage, and a household member is shown how to give it. Surgery needs a written plan with the anesthesiologist. Our traveling with a chronic condition article covers keeping the kit accessible on the road.
Heat, salt, and Florida
In primary disease the missing aldosterone is replaced with fludrocortisone, and the dose is judged by standing blood pressure, salt craving, and potassium. Summer here raises salt and water losses enough that some people need extra salt, more fluid, or a small fludrocortisone adjustment during the hottest months, and orthostatic hypotension returning is the usual sign. A hurricane medicine kit includes a month of tablets and the injection.
The order of treatment when thyroid disease is also present
Autoimmune adrenal disease often arrives with Hashimoto's thyroiditis, type 1 diabetes, or vitamin B12 deficiency, and one detail matters: when both adrenal and thyroid failure are found, cortisol is replaced before levothyroxine is started, because thyroid hormone speeds cortisol breakdown and can provoke a crisis. Over-replacement contributes to osteoporosis, so bone density is checked.
Adrenal fatigue is not this
Tiredness with normal cortisol testing is not a mild form of adrenal insufficiency, and taking steroid or "adrenal support" supplements for it can suppress the glands and create the real condition; our adrenal fatigue versus adrenal insufficiency article explains the difference. Our endocrine team manages replacement and the yearly review. The NIDDK and MedlinePlus publish patient guidance on daily management and emergencies.
If you have adrenal insufficiency and no emergency injection kit, or have never been shown how to use one, schedule a visit.