Addison's Disease: Understanding Adrenal Insufficiency and Steroid Replacement Therapy

When your body can’t make enough of the hormones that keep you alive, everyday life becomes a balancing act. For people with Addison’s disease, this isn’t theoretical-it’s daily reality. Addison’s disease, or primary adrenal insufficiency, happens when the adrenal glands are damaged and can’t produce enough cortisol and aldosterone. These aren’t optional hormones. Cortisol manages stress, blood sugar, and inflammation. Aldosterone controls salt and water balance. Without them, your body starts shutting down. And if you don’t know what’s wrong, it can kill you.

What Actually Causes Addison’s Disease?

Most cases-80 to 90% in the UK and other developed countries-are caused by the immune system attacking the adrenal glands. It’s an autoimmune mistake: your body turns on itself. This usually shows up as antibodies against 21-hydroxylase, a key enzyme in hormone production. The damage builds slowly. You lose function until 90% of the adrenal cortex is gone before symptoms appear. That’s why most people are diagnosed only after they’re already in crisis.

Decades ago, tuberculosis was the main cause. Today, it’s rare in places like the UK. But in parts of Africa and Asia, TB still accounts for over half of cases. Other rare causes include infections, cancer spreading to the adrenals, or genetic conditions. But if you’re in the UK, US, or Europe and you have adrenal insufficiency, it’s almost certainly autoimmune.

How Do You Know You Have It?

Symptoms creep in quietly. Fatigue. Weight loss. Low blood pressure. Nausea. Cravings for salt. These get written off as stress, depression, or the flu. The average person waits over three years before getting the right diagnosis. Gastroenterologists and GPs are often the first to see them-because the symptoms look like digestive problems.

But there are clues that point to Addison’s. Dark patches of skin, especially on knuckles, elbows, knees, and inside the mouth, are classic. That’s from high ACTH levels stimulating pigment cells. You might also have low sodium, high potassium, low blood sugar, and dizziness when standing up. These aren’t random. They’re the body screaming that it’s out of balance.

The test that confirms it is the ACTH stimulation test. You get a shot of synthetic ACTH, then your cortisol is checked 30 to 60 minutes later. If your cortisol doesn’t jump above 18 mcg/dL, your adrenals aren’t responding. Blood tests will also show high ACTH and low aldosterone. If your ACTH is high but aldosterone is normal, it’s probably not Addison’s-it’s secondary insufficiency, which comes from the pituitary, not the adrenals.

Steroid Replacement: The Lifesaving Routine

There’s no cure. But there is treatment: lifelong steroid replacement. You need two types.

First, glucocorticoids-usually hydrocortisone. This replaces cortisol. Most people take 15 to 25 mg a day, split into two or three doses. The first dose is higher in the morning to mimic your body’s natural rhythm. You might take 10 mg at 8 a.m., 5 mg at noon, and 5 mg at 5 p.m. Some newer options, like Chronocort, are designed to release slowly and mimic natural patterns better, reducing spikes and crashes.

Second, mineralocorticoids-fludrocortisone. This replaces aldosterone. You take 50 to 300 micrograms daily. It helps your kidneys hold onto salt and water. Without it, you get dangerously low blood pressure and high potassium. Your doctor will monitor your sodium, potassium, and blood pressure to adjust the dose.

It’s not just about taking pills. It’s about knowing when to change them.

The Sick Day Rules: When Illness Becomes a Crisis

The biggest danger isn’t missing a dose on a normal day. It’s missing it when you’re sick.

Infection, vomiting, surgery, even a bad cold-these can trigger adrenal crisis. Your body needs up to three times more cortisol just to cope. If you don’t increase your dose, your blood pressure can crash, your blood sugar can drop, and you can go into shock.

The Addison’s Disease Self Help Group has clear rules:

• At the first sign of illness-fever, cough, diarrhea-double or triple your hydrocortisone dose.
• If you can’t keep pills down because of vomiting, you need an injection.
• Always carry an emergency hydrocortisone injection kit. Know how to use it.
• If you’re vomiting, unconscious, or too weak to swallow, give yourself a 100 mg intramuscular shot immediately.

Many people don’t know this. A 2022 study showed 78% of patients had at least one adrenal crisis in five years-even those who took their pills regularly. Why? Because they didn’t adjust during illness.

Medical Alert and Emergency Preparedness

Wearing a medical alert bracelet isn’t optional. It’s mandatory. If you collapse in public, paramedics won’t know you have Addison’s unless you tell them. And if they don’t know, they won’t give you the steroids you need.

In the UK, 92% of patients who wore medical ID and carried emergency kits had 50% lower death rates from crisis. That’s not a small difference. That’s life or death.

You should also carry a steroid card or letter from your endocrinologist. It tells emergency staff exactly what to do. If you’re in hospital for surgery, your dose needs to be adjusted-often to 100 mg IV on the day of the procedure. Dentists need to know too. A simple filling might require an extra 25 mg of hydrocortisone.

The Hidden Costs and the Struggle to Get Care

Hydrocortisone isn’t expensive in theory. But in the US, without insurance, a month’s supply can cost $350 to $500. Even in the UK, some patients ration pills because of prescription charges or delays in renewals. One in four patients admit to cutting doses to make them last.

Finding doctors who understand is another hurdle. Many GPs haven’t seen a case in years. Patients on Reddit say things like, “Finding someone who gets that I need to take extra hydrocortisone at 3 a.m. during a fever is nearly impossible.”

The good news? Patients who complete the Addison’s Self Help Group’s “Sick Day Rules” training cut their crisis frequency by 85%. Education saves lives.

What’s Next for Treatment?

The field is moving. Chronocort, a modified-release hydrocortisone approved in 2023, gives more stable levels with once-daily dosing. Early data shows 37% fewer cortisol spikes and dips than standard tablets. That means fewer mood swings, less fatigue, and better sleep.

Researchers are testing wearable devices that monitor cortisol levels in real time. If they work, they could alert you before a crisis hits-like a glucose monitor for diabetics. One expert predicts these could reduce crisis rates by 60% within five years.

But even with better drugs, the biggest problem remains: awareness. The global prevalence of Addison’s is rising-10 to 14 cases per 100,000 people-and it’s increasing by 15% each year. Why? Because we’re testing for antibodies more often. We’re diagnosing earlier.

Living with Addison’s: A Life of Precision

Addison’s disease isn’t a death sentence. It’s a chronic condition that demands discipline. You can work, travel, raise kids, run marathons. But you have to be the expert on your own body.

You learn to track your symptoms. You know when your sodium is low because you feel weak and dizzy. You know when your fludrocortisone is too high because your ankles swell. You learn to say no to parties when you’re tired. You carry your injection kit everywhere-even to the beach.

The life expectancy gap is real. Studies show people with Addison’s live 3 to 11 years less than average, mostly from heart problems caused by long-term steroid use or sudden crisis. But those who stick to their regimen, know their sick day rules, and get regular monitoring can live full, active lives.

It’s not about being perfect. It’s about being prepared. One missed dose on a normal day? You’ll probably be fine. One missed dose during a fever? That’s when you risk dying.

Frequently Asked Questions