Addison’s disease is a rare condition in which your adrenal glands, two small glands that sit on top of your kidneys, stop producing enough of the hormones your body needs to regulate blood pressure, metabolism, and fluid balance. It affects roughly 100 to 140 out of every million people in developed countries. The condition is treatable with daily hormone replacement, but it requires lifelong management and carries the risk of a potentially life-threatening emergency called an adrenal crisis.
What Your Adrenal Glands Actually Do
Your adrenal glands produce two hormones that are central to Addison’s disease: cortisol and aldosterone. Cortisol helps your body break down fats, proteins, and carbohydrates. It regulates blood pressure, controls inflammation, and shapes how your immune system responds to threats. Your body also ramps up cortisol production during physical stress, like illness, injury, or surgery, to keep you functioning under pressure.
Aldosterone controls the balance of sodium and potassium in your blood. When aldosterone drops, your kidneys lose too much sodium and retain too much potassium. That leads to dehydration, low blood pressure, and disrupted signals in your muscles and heart. In Addison’s disease, both hormones decline because the outer layer of the adrenal gland, where they’re made, is progressively destroyed.
What Causes the Damage
In developed countries, 70% to 90% of Addison’s cases are caused by your own immune system attacking the adrenal glands. This autoimmune destruction happens gradually, often over months or years, and symptoms don’t appear until about 90% of the gland’s hormone-producing tissue is gone. Why the immune system targets the adrenal glands isn’t fully understood, but the process tends to cluster with other autoimmune conditions.
In developing nations, the picture is different. Infections, particularly tuberculosis, account for 39% to 51% of cases. In India, tuberculosis is the cause in nearly half of all adrenal failure. Other infectious causes exist but are far less common. Rarely, Addison’s can also result from bleeding into the adrenal glands, cancer that spreads to the adrenals, or genetic conditions that affect adrenal development.
How It Feels: Symptoms to Recognize
Addison’s disease develops slowly, which makes early symptoms easy to dismiss. Fatigue is usually the first thing people notice, a deep, persistent tiredness that doesn’t improve with rest. Weight loss follows, along with reduced appetite, nausea, and occasional vomiting. Many people experience dizziness when standing up, caused by blood pressure that drops too low.
One distinctive sign is skin darkening, especially in areas exposed to friction or sun: knuckles, elbows, knees, scars, lips, and the inside of the cheeks. This happens because when cortisol drops, your brain floods the bloodstream with a signaling hormone called ACTH in an attempt to wake up the adrenal glands. ACTH shares a chemical ancestor with the hormone that triggers pigment production in your skin, so high ACTH levels cause melanin to build up. This darkening can be subtle in people with lighter skin and easy to overlook in people with darker skin.
Other common symptoms include salt cravings (your body’s way of compensating for sodium loss), muscle or joint pain, irritability, depression, and low blood sugar. Women may notice a loss of body hair or changes in their menstrual cycle.
How Addison’s Is Diagnosed
Diagnosis typically starts with blood tests checking cortisol and ACTH levels. In Addison’s disease, cortisol is low while ACTH is abnormally high, because the brain keeps sending signals that the adrenal glands can’t answer. Blood tests also often reveal low sodium and high potassium.
The key confirmatory test is the ACTH stimulation test. You receive an injection of synthetic ACTH, and your cortisol level is measured 30 to 60 minutes later. Historically, a normal response was defined as a cortisol level reaching 18 micrograms per deciliter or higher. More recent research using modern, more precise lab assays has suggested the threshold should be closer to 14 to 15 micrograms per deciliter, which reduces the number of false positive results. If your cortisol fails to rise adequately after the injection, it confirms your adrenal glands aren’t responding.
Once adrenal insufficiency is confirmed, your doctor will typically check for antibodies against the adrenal glands to determine whether the cause is autoimmune. Imaging of the adrenal glands can help identify other causes, like tuberculosis or tumors.
Daily Treatment and Hormone Replacement
Treatment replaces the hormones your adrenal glands no longer make. The standard daily dose of hydrocortisone (a synthetic form of cortisol) is 15 to 25 mg, taken in divided doses throughout the day to mimic your body’s natural rhythm. Cortisol production normally peaks in the early morning and tapers off at night, so you’ll typically take a larger dose when you wake up and a smaller dose later in the day.
Because Addison’s disease also knocks out aldosterone production, most people take a second medication, fludrocortisone, to keep sodium and potassium in balance. Your doctor adjusts this dose based on blood pressure readings and lab work tracking your electrolyte levels.
With consistent treatment, most people with Addison’s disease live normal, active lives. But the medication must be taken every day without exception. Missing doses or failing to adjust them during illness can trigger a dangerous drop in cortisol.
Adrenal Crisis: The Emergency to Prepare For
An adrenal crisis happens when your body’s cortisol demand spikes, during a stomach bug, a high fever, surgery, or severe emotional stress, and your medication dose isn’t enough to cover the gap. It can also occur if you miss your medication entirely or can’t keep pills down due to vomiting.
Early signs include severe weakness, nausea, vomiting, abdominal pain, dizziness, and confusion. Blood pressure drops, sometimes to a systolic reading below 100 mm Hg. Without treatment, it can progress to circulatory collapse, loss of consciousness, and death. Fever can climb as high as 105°F. In children, an adrenal crisis may show up as severe low blood sugar with seizures.
Emergency treatment involves an injection of hydrocortisone and intravenous fluids. People with Addison’s disease are advised to carry an emergency injection kit and wear a medical alert bracelet at all times. Family members and close friends should know how to administer the injection if the person is too sick to do it themselves.
Adjusting Medication During Illness
The concept behind “sick day rules” is straightforward: when your body is under stress, it needs more cortisol than your standard daily dose provides. For a minor illness with fever, most endocrinologists recommend doubling or tripling your hydrocortisone dose for the duration of the illness. If you’re vomiting and can’t absorb oral medication, you’ll need to use your emergency injection.
Before any surgery or dental procedure, your medical team needs to know about your Addison’s disease so they can give you extra cortisol coverage. Even procedures done under local anesthesia can trigger enough stress to require a dose adjustment. Planning ahead for these situations is one of the most important parts of living with this condition.
Linked Autoimmune Conditions
When Addison’s disease has an autoimmune cause, it frequently appears alongside other autoimmune conditions. This clustering is called autoimmune polyendocrine syndrome, and it comes in two forms.
Type 1 is rarer and typically appears in childhood. It combines Addison’s disease with underactive parathyroid glands and chronic fungal infections of the skin and mucous membranes. Type 2, also called Schmidt’s syndrome, is more common and pairs Addison’s with type 1 diabetes, autoimmune thyroid disease, or both. Other conditions that may tag along in either type include vitiligo (patches of lost skin pigment), pernicious anemia (inability to absorb vitamin B12), and alopecia (hair loss).
If you’re diagnosed with Addison’s disease, your doctor will likely screen for thyroid problems and diabetes periodically, even if you don’t have symptoms yet. Catching these conditions early makes them far easier to manage.