Addison’s disease is a rare condition where your adrenal glands stop producing enough of the hormones your body needs to function normally. It affects roughly 100 to 140 out of every million people in developed countries. The adrenal glands, small organs sitting on top of each kidney, are responsible for making cortisol (your body’s stress and energy-regulation hormone), aldosterone (which controls salt and water balance), and certain sex hormones. When these glands are damaged or destroyed, the resulting hormone shortfall touches nearly every system in your body.
What Happens in the Adrenal Glands
The outer layer of each adrenal gland, called the cortex, is the production site for three key hormones. Cortisol helps regulate blood sugar, blood pressure, metabolism, and your immune response. Aldosterone tells your kidneys how much sodium to keep and how much potassium to release, which directly controls fluid balance and blood pressure. Androgens contribute to energy, mood, and muscle maintenance.
In Addison’s disease, the cortex on both adrenal glands is gradually destroyed. By the time symptoms appear, roughly 90% of the cortex is already gone. Without enough cortisol, your body can’t respond properly to physical stress, illness, or even routine demands like digesting food. Without aldosterone, sodium escapes through your urine faster than it should, pulling water with it. That’s why dehydration, low blood pressure, and intense salt cravings are hallmark features of the disease.
Why the Adrenal Glands Break Down
In most cases in developed countries, the immune system mistakenly attacks the adrenal cortex. This autoimmune destruction is the dominant cause and often occurs alongside other autoimmune conditions like thyroid disease or type 1 diabetes. Worldwide, tuberculosis remains a significant cause, particularly in regions where TB is still common. Less frequently, fungal infections, cancer that has spread to the adrenal glands, bleeding into the glands, or genetic conditions can be responsible.
Symptoms and Early Warning Signs
Addison’s disease tends to develop slowly, and early symptoms are easy to dismiss. Fatigue, muscle weakness, and a vague sense of being unwell are often the first things people notice. Weight loss, decreased appetite, nausea, and occasional vomiting or diarrhea follow. Many people develop low blood pressure that gets worse when standing up, causing lightheadedness. Joint and muscle pain, headaches, mood changes, and depression are also common.
One of the most distinctive signs is skin darkening, especially in areas exposed to friction or sunlight: knuckles, elbows, knees, skin folds, scars, lips, and the inside of the cheeks. This happens because of a chain reaction in the brain. When cortisol drops, the pituitary gland ramps up production of a signaling hormone called ACTH to try to stimulate the adrenal glands. A pigment-stimulating molecule is released alongside ACTH, which activates the cells responsible for skin color. This darkening often appears months or even years before other symptoms become obvious, making it a potentially early diagnostic clue.
Salt cravings deserve special mention. Because aldosterone is low, your body loses sodium rapidly. You may find yourself craving salty foods in a way that feels urgent and unusual. This isn’t a preference; it’s your body signaling a genuine electrolyte deficit.
How Addison’s Disease Is Diagnosed
Diagnosis typically involves a blood test called the ACTH stimulation test. You’re given a synthetic version of ACTH, the hormone that normally tells the adrenal glands to produce cortisol. Your cortisol levels are then measured 30 to 60 minutes later. Historically, a cortisol response below 18 micrograms per deciliter was considered diagnostic, but newer, more precise lab methods have pushed that cutoff down to around 14 to 15 micrograms per deciliter, depending on the specific assay used. A low cortisol response paired with high ACTH levels in the blood confirms that the problem originates in the adrenal glands themselves rather than in the brain’s signaling system.
Additional blood work typically reveals low sodium, high potassium, and sometimes low blood sugar. Antibody testing can help confirm an autoimmune cause. Imaging of the adrenal glands is occasionally used to look for structural damage, infection, or tumors.
Daily Hormone Replacement
Treatment replaces the hormones your adrenal glands no longer make. For cortisol, the standard approach is 15 to 25 milligrams of hydrocortisone daily, split into two or three doses to roughly mimic the body’s natural rhythm of higher cortisol in the morning and lower levels in the evening. Getting the dose right matters: too little leaves you fatigued and vulnerable, while too much over time can lead to weight gain, bone thinning, and other side effects of excess cortisol.
For aldosterone replacement, a synthetic version called fludrocortisone is taken once daily. Your doctor adjusts the dose based on blood pressure readings and a blood marker called plasma renin activity, which reflects how well your body is retaining sodium. Some people also benefit from a higher-sodium diet, though the exact amount should be tailored to your individual needs.
This hormone replacement is lifelong. Missing doses or running out of medication can be dangerous, so most people with Addison’s disease learn to keep extra supplies at home, at work, and while traveling.
Sick Day Rules and Stress Dosing
A healthy body naturally produces extra cortisol during illness, injury, or emotional stress. Your replacement dose doesn’t adjust automatically, so you need to increase it yourself when your body is under strain. These guidelines are called “sick day rules,” and learning them is one of the most important parts of managing Addison’s disease.
For a fever above 100.4°F (38°C), the standard recommendation is to double your daily hydrocortisone dose. If your fever rises above 102.2°F (39°C), triple it. This higher dose is typically maintained for two to three days during a minor illness and longer for more serious ones. Significant emotional stress, like a bereavement or a major exam, may call for an extra 10 milligrams of hydrocortisone to help your body cope. If you’re vomiting and can’t keep oral medication down, you need an emergency injection.
Adrenal Crisis
The most dangerous complication of Addison’s disease is adrenal crisis, a sudden, severe cortisol deficiency that can be life-threatening. Triggers include infections, surgery, injuries, vomiting that prevents you from absorbing oral medication, or simply forgetting to take your replacement hormones. Symptoms escalate quickly: severe weakness, confusion, abdominal pain, vomiting, dangerously low blood pressure, and sometimes loss of consciousness.
Adrenal crisis requires emergency treatment with an injection of 100 milligrams of hydrocortisone, given into a muscle or vein. Most people with Addison’s disease carry an emergency injection kit and wear a medical alert bracelet or card so that paramedics and emergency departments can act fast. Family members and close friends are encouraged to learn how to administer the injection in case the person is too ill to do it themselves.
Living With Addison’s Disease
With consistent hormone replacement, most people with Addison’s disease lead full, active lives. The daily routine of taking medication at the right times becomes second nature. Exercise is not only safe but encouraged, though you may need a small extra dose of hydrocortisone before unusually strenuous activity. Travel requires some planning: carrying extra medication, keeping an emergency kit accessible, and knowing how to reach medical care at your destination.
Regular follow-up appointments help fine-tune your doses over time. Weight changes, blood pressure shifts, and how you feel day-to-day all provide clues about whether your replacement is on target. Many people report that finding the right dose balance takes some patience, and adjustments are normal, especially during the first year after diagnosis.