If your body were a streaming service, cortisol would be the subscription you forget you pay foruntil it stops working.
Addison’s disease and Cushing disease sit on opposite ends of the cortisol spectrum: one is “not enough,” the other is “way too much.”
And because cortisol influences everything from blood pressure to blood sugar to how your immune system behaves, the symptoms can look like a
weird mashup of unrelated problems… until the pattern clicks.
In this guide, we’ll break down the real difference between Addison’s disease (primary adrenal insufficiency) and
Cushing disease (a specific cause of Cushing syndrome), including symptoms, causes, diagnosis, treatment, and what daily life often looks like.
You’ll also learn why people mix up “Cushing disease” with “Cushing syndrome,” and how clinicians sort it out without guessing.
The simplest difference: low cortisol vs. high cortisol
Addison’s disease happens when your adrenal glands don’t make enough cortisol (and often not enough aldosterone, too).
Cortisol helps you respond to stress, maintain blood pressure, and keep blood sugar stable. Aldosterone helps regulate salt and water balance.
Cushing disease is different: it’s a form of Cushing syndrome caused by a pituitary gland tumor that makes too much ACTH,
which tells the adrenal glands to produce too much cortisol. In other words, Cushing disease is a specific “upstream” trigger for cortisol overload.
Hormone crash course (no lab coat required)
Your body uses a hormone “text-message chain” called the HPA axis:
- Hypothalamus sends CRH (the “hey, check cortisol” message)
- Pituitary sends ACTH (the “adrenals, make cortisol” message)
- Adrenal glands produce cortisol (the “done!” messageplus lots of side effects)
In Addison’s disease, the adrenal glands can’t deliver the cortisol “done!” message.
In Cushing disease, the pituitary won’t stop texting ACTH, so cortisol keeps pouring out.
Addison’s vs. Cushing: at-a-glance comparison
| Feature | Addison’s disease (Primary adrenal insufficiency) | Cushing disease (Pituitary cause of Cushing syndrome) |
|---|---|---|
| Cortisol level | Too low | Too high |
| Main “source” of problem | Adrenal glands (often autoimmune damage) | Pituitary gland (ACTH-secreting adenoma) |
| Classic body changes | Weight loss, low blood pressure, skin darkening | Central weight gain, rounder face, skin thinning, purple stretch marks |
| Electrolytes | Often low sodium; may have high potassium (due to low aldosterone) | Not a signature feature; can have high blood sugar and other metabolic changes |
| Big risk | Adrenal crisis (medical emergency) | Complications like diabetes, hypertension, infections, fractures, blood clots |
| Typical treatment direction | Replace missing hormones | Remove/stop the cause of excess cortisol |
Symptoms: how they feel in real life
Addison’s disease symptoms (too little cortisol)
Addison’s disease can creep in slowly, which is part of why it’s often misread as stress, stomach issues, depression, or “just getting older.”
Common symptoms include:
- Fatigue and muscle weakness that doesn’t match your sleep or fitness level
- Weight loss and reduced appetite
- Low blood pressure (especially dizziness when standing)
- Salt cravings (your body is basically begging for sodium)
- Nausea, abdominal pain, or intermittent vomiting
- Skin darkening (hyperpigmentation), especially in creases, scars, or gums (more typical in primary Addison’s)
- Low blood sugar can happen, particularly in children but also some adults
A key clue: in primary adrenal insufficiency (Addison’s), aldosterone may also be low. That can lead to dehydration, low sodium, and sometimes high potassium.
Clinicians often notice this pattern in lab results alongside symptoms.
Cushing disease symptoms (too much cortisol)
Cushing disease is a “too much cortisol for too long” scenario. Cortisol affects fat distribution, muscle strength, skin integrity,
mood, blood pressure, and glucose. People may notice:
- Weight gain, especially in the abdomen and upper back (while arms and legs may look thinner)
- Rounder face (“moon face”) and fat pad at the upper back (“buffalo hump”)
- Thin, fragile skin that bruises easily and heals slowly
- Wide pink or purple stretch marks (often on the abdomen, hips, thighs, breasts, or arms)
- Muscle weakness (especially getting up from a chair or climbing stairs)
- High blood pressure and high blood sugar (sometimes new diabetes)
- Mood changes (irritability, anxiety, depression) and sleep disruption
- Menstrual changes, fertility issues, and sometimes increased facial/body hair in women
- Bone loss and fractures with minor trauma
One reason Cushing disease can be tricky is that weight gain, fatigue, and mood changes are common in many conditions.
The more “signature” featureslike purple stretch marks, easy bruising, muscle weakness, and classic fat redistributionhelp narrow the suspicion.
Causes: where each condition actually starts
What causes Addison’s disease?
Addison’s disease is primary adrenal insufficiency, meaning the adrenal glands themselves are damaged and can’t make enough hormones.
In the United States and other developed countries, the most common cause is autoimmune adrenalitis (your immune system attacks the adrenal cortex).
Less common causes include infections, bleeding into the adrenal glands, cancer spread to the adrenal glands, or certain genetic and rare disorders.
It’s also important to know about secondary adrenal insufficiency, which is not Addison’s disease but can look similar.
Secondary adrenal insufficiency happens when the pituitary doesn’t produce enough ACTH, so the adrenals don’t get the signal to make cortisol.
Another common pathway: stopping long-term steroid medication suddenly. In that situation, the body’s cortisol production can be “asleep,” and it needs time to restart.
What causes Cushing disease?
Cushing syndrome is the umbrella term for chronic cortisol excess, and the most common overall cause is
long-term glucocorticoid medication (like prednisone) used to treat inflammatory or autoimmune conditions.
That’s called iatrogenic Cushing syndrome.
Cushing disease is narrower: it’s Cushing syndrome caused by a pituitary adenoma that makes excess ACTH,
which drives the adrenal glands to overproduce cortisol. Other non-pituitary causes of Cushing syndrome include adrenal tumors
(making cortisol directly) or ectopic ACTH production from tumors elsewhere in the body.
Diagnosis: how clinicians confirm it (and avoid the “Google spiral”)
Testing for Addison’s disease (and adrenal insufficiency)
Providers usually start with a careful symptom review, blood pressure assessment (including standing vs. sitting),
and basic labs (electrolytes and glucose). The key hormone tests often include:
- Morning cortisol (cortisol should be higher in the early morning)
- ACTH level (often high in Addison’s, low/normal in secondary causes)
- ACTH stimulation test (cosyntropin test) to see whether the adrenals can respond
If primary adrenal insufficiency is suspected, clinicians may also check aldosterone and renin,
and sometimes adrenal antibodies, depending on the clinical picture. Imaging (CT or MRI) may be used to look for structural causes.
Testing for Cushing disease (and Cushing syndrome)
Diagnosing cortisol excess requires confirming that cortisol is consistently high when it should be low. Many guidelines recommend one (or more)
of these initial screening tests:
- Late-night salivary cortisol (cortisol should be low late at night)
- 24-hour urinary free cortisol (measures cortisol output over a full day)
- Low-dose dexamethasone suppression test (checks whether cortisol “turns down” when it should)
If Cushing syndrome is confirmed, the next step is figuring out the source. A key fork in the road is the ACTH level:
low ACTH suggests the adrenal glands are overproducing cortisol on their own; high ACTH suggests an ACTH-driven source,
such as a pituitary tumor (Cushing disease) or ectopic ACTH production.
For suspected Cushing disease, imaging like a pituitary MRI may be used. In challenging cases, specialized testing (such as sampling blood from veins
that drain the pituitary) may help confirm the source.
Treatment: replacing what’s missing vs. removing what’s excessive
How Addison’s disease is treated
Addison’s disease is typically managed with lifelong hormone replacement. The goal is to replace what the body isn’t making:
- Glucocorticoid replacement (commonly hydrocortisone, or sometimes prednisone/prednisolone)
- Mineralocorticoid replacement (often fludrocortisone) when aldosterone is low
A major part of living well with Addison’s is learning “stress dosing” conceptsbecause during illness, surgery, or major physical stress, healthy bodies
naturally produce more cortisol. People with Addison’s often need medically guided adjustments during these times.
This is also why clinicians emphasize emergency planning and recognizing warning signs early.
How Cushing disease is treated
Treatment for Cushing syndrome depends on the cause:
- If it’s from steroid medication, clinicians typically aim to reduce or taper the medication safely when possible (never abruptly on your own).
- If it’s Cushing disease from a pituitary adenoma, first-line treatment is often surgery to remove the tumor.
- If surgery isn’t possible or doesn’t fully resolve cortisol excess, additional options may include medications that reduce cortisol production,
radiation therapy, or (in select cases) adrenal surgery.
Even after treatment, recovery can take time. Cortisol affects muscle and bone, metabolism, and moodso rebuilding strength and normal rhythms can be a gradual process.
Urgent red flags: when it’s not a “wait-and-see” situation
Addison’s disease: An adrenal crisis is a medical emergency. Symptoms can include severe weakness, confusion,
significant vomiting/diarrhea, dehydration, very low blood pressure, or faintingespecially during infection, injury, or after missing steroid doses.
Emergency treatment typically involves prompt hydrocortisone and IV fluids in a hospital setting.
Cushing disease: Cortisol excess can raise the risk of serious complications (like infections, blood clots, uncontrolled diabetes, and fractures).
Seek urgent care for severe infection symptoms, sudden shortness of breath or chest pain, signs of stroke, or severe high blood sugar symptoms.
Common mix-ups (and how to keep them straight)
- “Cushing disease” vs “Cushing syndrome”: Cushing syndrome is the umbrella. Cushing disease is specifically pituitary ACTH overproduction.
-
Addison’s disease vs secondary adrenal insufficiency: Addison’s is primary adrenal failure. Secondary forms often involve the pituitary or steroid withdrawal
and may not have the same aldosterone-related electrolyte pattern. - “I’m tired, so it must be cortisol.” Fatigue shows up everywhere. The diagnosis depends on patterns, labs, and targeted testingnot vibes, not viral videos.
What “living with it” often feels like (500-word experience section)
People’s experiences with Addison’s disease and Cushing disease are often less like a dramatic TV diagnosis and more like a slow-burn mystery novel:
lots of chapters where nothing makes sense, followed by one page where everything suddenly does.
With Addison’s disease, a common story is months (or years) of feeling “off.” Someone may describe being exhausted after normal activities,
skipping meals because they’re not hungry, losing weight without trying, and getting dizzy when standing up. Friends might say, “Maybe you’re just stressed,”
and the person starts to believe ituntil symptoms ramp up. Some people remember the salt cravings as oddly specific:
they suddenly want pickles, chips, or salty broths like it’s their full-time job. Others notice skin changes that are easy to miss day-to-day:
darkening around knuckles, scars, gums, or skin creases. Many describe relief when the diagnosis finally has a name, and frustration that it took so long
because the symptoms looked “too general” at first.
After diagnosis, the learning curve can feel real. People often talk about how they had to become organized overnightcarrying medication,
understanding sick-day planning from their care team, and paying attention to early signs of dehydration or illness.
The goal isn’t to live in fear; it’s to live with a plan. Many say that once they find the right replacement dosing schedule,
their energy becomes more predictable and they feel like themselves againjust with better calendar skills.
With Cushing disease, experiences frequently center on changes that feel unfairly visible. People might gain weight in the abdomen and face
while arms and legs seem to thin, which can be emotionally tough because it doesn’t match “normal” weight gain patterns.
Others describe skin that bruises easily, stretch marks that appear quickly, and muscle weakness that makes stairs feel like a personal attack.
Because these changes can overlap with other conditions, some people report feeling dismisseduntil the combination of symptoms (and testing) points clearly to hypercortisolism.
Treatment can be a turning point but not always an instant fix. Patients often describe surgery (when a pituitary tumor is involved) as both hopeful and intimidating.
Recovery can include a period where the body needs time to reset its hormone signaling, and people may feel fatigued or emotionally “out of sync” during that transition.
Many find it validating to learn that the mood changes, sleep issues, and concentration problems were part of cortisol’s influencenot personal weakness.
Over time, small wins matter: blood pressure improves, glucose stabilizes, strength returns, and the face shape gradually changes.
A theme you hear a lot is patience: rebuilding after cortisol overload is often measured in months, not days.
Across both conditions, a shared experience is this: once people understand the physiologywhat cortisol does and why extremes cause specific patternsthey feel more empowered.
They’re better able to describe symptoms clearly, recognize red flags, and work with endocrinology teams using real data instead of guesswork.
In short, the body stops feeling like a confusing black box and starts acting more like a system with rules (annoying rules, surebut rules).
Conclusion
Addison’s disease and Cushing disease are both cortisol disorders, but they’re opposites in hormone output and often opposites in physical presentation.
Addison’s disease is primarily about hormone deficiency (replace what’s missing and prevent adrenal crisis).
Cushing disease is about hormone excess driven by a pituitary source (confirm cortisol overload, identify the cause, and treat the driver).
If you suspect either condition, the best next step is targeted medical evaluation. These aren’t diagnoses you can “power through,”
but they are conditions where accurate testing and evidence-based treatment can dramatically improve quality of life.
