Addison's Disease in Cats: How Common Is It?
By Dr. Zubair Khalid, DVM, MS, PhD ·
Addison's disease is very rare in cats. Only about 40 cases have been documented in the 40 years since the condition was first described in 1983 [1]. That makes it one of the least common endocrine disorders your veterinarian will ever diagnose in a cat. This article is educational and is not a substitute for veterinary diagnosis or treatment.
Quick Answer
- Feline Addison's disease (hypoadrenocorticism) is extremely rare, with roughly 40 published cases over four decades [1].
- It happens when the adrenal glands stop making enough glucocorticoids, mineralocorticoids, or both [2].
- Cats often show vague signs that come and go, such as vomiting, weight loss, weakness, and poor appetite [2][3].
- Diagnosis is confirmed with an ACTH stimulation test, which must be done before starting steroids [1][3].
- Treatment is lifelong but usually successful, and most cats improve once hormone replacement begins [2][1].
What Is Addison's Disease in Cats?
The adrenal glands sit just in front of the kidneys. Each gland has two parts, the cortex and the medulla [4]. The cortex makes three groups of steroid hormones from three separate layers. The outer layer makes mineralocorticoids, which control sodium and potassium balance. The middle layer makes glucocorticoids, which help metabolize nutrients and dampen inflammation. The inner layer makes sex hormones [4]. The medulla releases epinephrine and norepinephrine, which raise heart output, blood pressure, and blood glucose during stress or low blood sugar [4].
Addison's disease, also called hypoadrenocorticism, means the cortex is not producing enough glucocorticoids, mineralocorticoids, or both [2]. When mineralocorticoids are missing, the body loses sodium and holds onto potassium, which disrupts the heart, blood pressure, and fluid balance. When glucocorticoids are missing, cats lose their ability to handle stress and may develop low blood sugar, poor appetite, and lethargy.
Isolated aldosterone (mineralocorticoid) deficiency appears to be very rare, and isolated glucocorticoid deficiency is likely underdiagnosed because it does not cause electrolyte abnormalities on a routine blood panel [2]. That last point matters. A cat can have Addison's disease with completely normal sodium and potassium values, which is one reason the condition is easy to miss.
How Common Is Addison's Disease in Cats?
It is rare. A 2024 review of the veterinary literature found only about 40 documented feline cases since 1983 [1]. A 2025 multicenter study described 41 cats, which is one of the largest groups ever assembled, and it took many hospitals years to collect them [5]. For comparison, Addison's disease is a well-recognized and much more common disorder in dogs [1].
The rarity has real consequences. Most veterinarians will see few or no cases in their career. Cats with the condition often get treated for other problems first, and the diagnosis gets delayed. One review noted that when cats improve on corticosteroids given for another reason, that temporary improvement can push the correct diagnosis even further away [1].
How Rare Is Addison's Disease in Cats Compared With Other Conditions?
If you are searching because your cat has been vomiting or losing weight, Addison's disease is far down the list. Chronic kidney disease in cats is common in older cats and can cause similar signs, including weight loss, poor appetite, and vomiting. Symptoms of kidney disease in my cat overlap with several of the vague signs of Addison's disease, which is exactly why your veterinarian will start with basic blood work and a urinalysis.
Cat Addison's Disease Symptoms: What Owners Notice
The signs are often vague and can wax and wane over days, weeks, or months before diagnosis [2]. Owners frequently describe a cat who "just isn't right." Common findings include:
- Vomiting and diarrhea
- Weight loss
- Poor appetite or hyporexia
- Lethargy and weakness
- Hiding behavior
- Poor growth in young cats
- Episodes of collapse or shock
A 2025 study of 41 cats found a median age of 5.7 years, with a range from 0.2 to 13.8 years. Twenty-three cats (56%) were male and 18 (44%) were female [5]. Cats with low sodium, high potassium, or both were less likely to have a history of vomiting but more likely to be hypothermic, dehydrated, or weak on examination [5].
Some cats present dramatically. One case report described a 4-year-old Ragdoll who came in for generalized seizures caused by severe low blood sugar, with a 12-month history of daily vomiting and fast breathing beforehand [6]. Another report described a 7-week-old kitten who was weak, dehydrated, and hypotensive after surgery, with low sodium and high potassium [7]. These are extreme examples, but they show how widely the condition can present.
If your cat's main sign is vomiting, it helps to know what is ordinary and what is not. Cat vomiting hairballs: how often is too often? covers the everyday end of that spectrum, while persistent vomiting with weight loss belongs in a veterinary exam.
Signs That Point Toward an Emergency
Weakness, collapse, a slow or irregular heartbeat, or a cat who cannot stand are emergencies. These can reflect severe electrolyte imbalances or low blood sugar, and they need immediate care.
Causes and Risk Factors
Primary hypoadrenocorticism means the problem starts in the adrenal glands themselves. In one cat, post-mortem examination found lymphoplasmacytic adrenalitis, an inflammation of the adrenal gland, with a T-cell rich lymphocytic infiltrate. That pattern supports an autoimmune cause, where the body's immune system attacks the adrenal tissue [8].
Secondary hypoadrenocorticism would mean the pituitary gland is not sending enough ACTH to tell the adrenals to work. Both forms lead to the same shortage of hormones.
Breed may play a small role. One review noted that British Shorthair cats may be overrepresented among affected cats, so clinicians should be especially alert when that breed shows compatible signs [3]. Age and sex do not narrow things down much, since cases have been reported from very young kittens to older adults, in both males and females [5].
A low sodium to potassium ratio is a classic clue, but it is uncommon in cats and can appear with other conditions. These include severe kidney disease, cardiovascular disease, cavitary effusion, and certain gastrointestinal diseases [9]. One case report described a 1-year-old Maine Coon with severe electrolyte abnormalities and a Tritrichomonas foetus infection. ACTH stimulation testing ruled out hypoadrenocorticism, and the electrolytes normalized after antiprotozoal treatment [9]. In other words, a bad sodium to potassium ratio does not prove Addison's disease. It starts a conversation.
How Is Feline Hypoadrenocorticism Diagnosed?
Diagnosis depends on history, physical examination, and screening laboratory tests such as a complete blood count, chemistry panel, and urinalysis [2]. Confirmation requires adrenal function testing with an ACTH stimulation test [2][1].
Step 1: Screening Tests
Your veterinarian will look for low sodium, high potassium, low blood sugar, and other clues. Remember that some cats with Addison's disease have normal sodium and potassium, so normal electrolytes do not rule it out [2][5].
Step 2: Baseline Cortisol
In clinically stable cats, a baseline cortisol measurement may be used as an initial screening tool [3]. There is a catch. No feline-specific cutoff has been validated, so the commonly used threshold of greater than 2 µg/dL (greater than 55 nmol/L) to rule out hypoadrenocorticism should be interpreted with caution in cats, because it may be less reliable than in dogs [3].
Step 3: ACTH Stimulation Test
This is the definitive test. A low resting cortisol with an inadequate or absent response to synthetic ACTH is diagnostic [1]. Published protocols vary, and most use three time-limited blood samples [1]. That can be hard on a sick or stressed cat, so your veterinarian will decide how to balance the testing protocol against your cat's comfort and condition.
Timing matters a great deal. The ACTH stimulation test should be performed before any glucocorticoid treatment starts, because steroids interfere with the results [3].
A Simple Comparison
| Feature | Addison's Disease in Dogs | Addison's Disease in Cats |
|---|---|---|
| How common | Well-recognized, more common [1] | Very rare, about 40 cases in 40 years [1] |
| Typical signs | Often clear, including weakness and vomiting | Vague and waxing and waning [2][1] |
| Electrolyte changes | Common | Present in many but not all cats [5] |
| Baseline cortisol screening | Reliable in dogs | Less reliable, no validated feline cutoff [3] |
| Definitive test | ACTH stimulation test [2] | ACTH stimulation test [2][1] |
Treatment Options
Treatment is highly successful but often lifelong [2]. It has two parts, replacing glucocorticoids and replacing mineralocorticoids when they are deficient.
Glucocorticoid replacement is usually given as oral prednisolone. Cats generally require higher maintenance doses than dogs, and your veterinarian will calculate the dose based on your cat's weight, test results, and response to treatment [3]. Mineralocorticoid replacement may be given as an injection such as desoxycorticosterone pivalate or as an oral medication, depending on your cat and your veterinarian's plan.
During a crisis, treatment starts with intravenous fluids, corticosteroids, and close monitoring. One 7-week-old kitten was treated with IV fluids, corticosteroids, and subcutaneous desoxycorticosterone pivalate, and was doing well three months later on a decreasing glucocorticoid dose [7].
Doses are never one-size-fits-all. Your veterinarian sets the dose and adjusts it over time based on your cat's clinical signs and electrolyte values.
Recovery, Outlook, and Long-Term Management
Most cats improve once hormone replacement begins, and many return to a normal life. The catch is that treatment usually continues for life, and monitoring never really stops.
Expect regular veterinary visits with blood work to check sodium, potassium, and glucose. Your veterinarian may adjust doses based on those results and on how your cat is acting at home. Keep a simple log of appetite, energy, vomiting, and any episodes of weakness. That record is genuinely useful at appointments.
Some cats have other conditions alongside Addison's disease, which can complicate management. One cat was diagnosed with primary hypoadrenocorticism along with exocrine pancreatic insufficiency, cobalamin deficiency, and chronic enteropathy, and later developed diabetes mellitus [8]. That is an unusually complex case, but it shows why ongoing monitoring matters.
One more point about long-term care. A kitten treated for hypoadrenocorticism was doing well after three months, and the owners, concerned about frequent visits and medication cost, chose to extend the mineralocorticoid dose interval with close monitoring of clinical status and electrolytes [7]. Cost and visit frequency are fair things to discuss openly with your veterinarian. Never change a dosing schedule on your own.
Prevention
There is no known way to prevent Addison's disease in cats. The suspected autoimmune mechanism means there is no diet, supplement, or lifestyle change that lowers the risk [8].
What you can do is pay attention. If your cat has repeated vomiting, weight loss, or episodes of weakness that come and go, ask your veterinarian whether adrenal function testing is worth considering. Early diagnosis prevents a crisis. Also tell your veterinarian about every medication and supplement your cat receives, since steroids can interfere with the ACTH stimulation test [3].
Limitations and When to Contact a Veterinarian
Feline Addison's disease is rare, and no article can tell you whether your individual cat has it. Your cat needs a veterinarian who can examine them, run tests, and interpret the results in context.
Contact your veterinarian the same day if your cat:
- Vomits repeatedly or cannot keep food or water down
- Stops eating for more than 24 hours
- Seems weak, wobbly, or unusually quiet
- Has diarrhea that lasts more than a day
Go to an emergency clinic now if your cat:
- Collapses or cannot stand
- Has a seizure
- Breathes fast at rest or has a racing or irregular heartbeat
- Is unresponsive or barely responsive
Schedule a routine visit if your cat has slow, unexplained weight loss, intermittent vomiting over weeks, or a pattern of good days and bad days. Bring notes about when signs started and how often they occur. That history helps your veterinarian decide which tests to run first.
Frequently Asked Questions
Can a cat survive Addison's disease?
Yes. Treatment is highly successful, though it is usually lifelong [2]. With consistent medication and monitoring, most cats improve and return to a good quality of life.
Does Addison's disease in cats always cause abnormal electrolytes?
No. Some cats have normal sodium and potassium values, which is part of why the condition is underdiagnosed [2][5]. A normal electrolyte panel does not rule it out.
Is Addison's disease in cats the same as in dogs?
No. The underlying hormone shortage is similar, but the disease is far more common and better recognized in dogs [1]. Cats also tend to have vaguer signs and less reliable baseline cortisol screening [1][3].
Can a low sodium to potassium ratio alone confirm Addison's disease?
No. That ratio can also drop with severe kidney disease, heart disease, cavitary effusion, and some gastrointestinal diseases, including infections [9]. Confirmation requires an ACTH stimulation test [2][1].
Can kittens get Addison's disease?
Yes, though it is rare at any age. Cases have been reported in kittens as young as 7 weeks [7], and the age range in one case series ran from 0.2 to 13.8 years [5].
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References
- Hypoadrenocorticism in cats: a 40-year update. Journal of feline medicine and surgery, 2024.
- Addison Disease (Hypoadrenocorticism) in Animals - Endocrine System. Merck Veterinary Manual.
- Feline hypoadrenocorticism: Emerging insights into clinical features, diagnosis, and treatment. Schweizer Archiv fur Tierheilkunde, 2026.
- Disorders of the Adrenal Glands in Cats - Cat Owners. Merck Veterinary Manual.
- Clinical findings, treatment, and outcomes in cats with naturally occurring hypoadrenocorticism: 41 cases. Journal of veterinary internal medicine, 2025.
- Successful treatment of atypical hypoadrenocorticism in a cat presenting with hypoglycaemic seizures. JFMS open reports, 2025.
- Transient Hypoadrenocorticism in a 7-Week-Old Kitten. Journal of the American Animal Hospital Association, 2025.
- Histopathological evaluation of the adrenal glands in a cat with primary hypoadrenocorticism and multiple endocrine disease. JFMS open reports, 2022.
- Hypoadrenocorticism-like syndrome in a cat with Tritrichomonas foetus infection: a case report. The Journal of small animal practice, 2026.