Addison’s Disease in Dogs: Emergency Signs, Testing and Life With Treatment

An Addisonian crisis is a sudden, life-threatening drop caused by severe adrenal hormone deficiency. The Merck Veterinary Manual describes it as involving dehydration, low blood pressure, shock, severe vomiting or diarrhea, low blood sugar, and dangerous changes in sodium and potassium. High potassium can slow or disrupt the heart's rhythm.

Go to an emergency clinic right away for any of these:

• Collapse, or a dog who can't stand
• Severe weakness that is getting worse fast
• Repeated vomiting or severe diarrhea
• Marked dehydration
• Pale or abnormal gums along with weakness
• A very slow heartbeat
• A dog who is hard to rouse or acting strangely

These signs don't prove Addison’s. They are emergency signs for any dog, and the clinic will work out the cause. Call ahead if you can, and bring any medication list you have. If your dog is already diagnosed, tell the clinic right away that your dog has Addison’s disease. Our articles on dog vomiting and dog diarrhea cover ordinary cases, but in a dog with possible Addison’s, vomiting can be more serious and needs faster care.

The adrenal glands sit near the kidneys and make two groups of hormones. Cortisol, a glucocorticoid, helps with metabolism, digestion, blood sugar, immune balance and the response to stress. Aldosterone, a mineralocorticoid, helps control sodium, potassium, fluid balance and blood pressure. You may also hear the names adrenal insufficiency or hypoadrenocorticism. They all point to the same problem.

In typical Addison’s, the outer layer of the adrenal gland is damaged and both hormones run short. In atypical Addison’s, cortisol is low but sodium and potassium stay in the usual lab range. Some dogs have a secondary form, caused by too little ACTH signal from the pituitary gland or by stopping long-term steroids suddenly, per the Merck Veterinary Manual.

The most common cause of the natural disease is the immune system damaging adrenal tissue, and AAHA’s 2023 guidelines describe it that way. Less common causes include infection, cancer, and adrenal suppression from treatment. If your dog was treated for Cushing’s disease, your vet may keep this in mind; our Cushing’s disease article covers that condition, which is the opposite problem, too much cortisol.

Any dog of any age or sex can get it. Diagnosis often comes in young or middle-aged dogs, and older dogs can be affected too. A female tendency has been reported, but not consistently. A hereditary link is suspected in some breeds. Standard Poodles, Portuguese Water Dogs, Great Danes, Bearded Collies, West Highland White Terriers and Nova Scotia Duck Tolling Retrievers are reported as overrepresented, and mixed-breed dogs can have it too. Being in one of those breeds is a risk factor, not a prediction.

Possible signs include low energy, poor appetite, weight loss, vomiting, diarrhea, weakness, trembling, dehydration, and more drinking and urinating than usual. Cornell and Merck both describe these signs as vague and nonspecific.

They can come and go. Hormone shortfalls can be partial and variable, and illness or stress can make signs worse, so a dog may seem sick, perk up, then slump again. That pattern is one reason the disease is often missed at first. Cornell lists it among conditions that can mimic stomach trouble, kidney disease, infection, pancreatitis, poisoning, low blood sugar and other hormone problems. In a 2022 owner survey of 308 dogs, reported in Veterinary Record, nearly half were diagnosed after a sudden adrenal crisis.

Here is the plan I'd follow. If your dog has been off, tired or queasy on and off for days or weeks, book a vet visit soon and describe the pattern, including the good days. If the signs ever turn into the emergency list above, skip the appointment and go to the emergency clinic. A list of signs can't diagnose Addison’s, so please don't rule it in or out from a checklist, and don't change any medication on your own. If your dog is a senior, our senior dog care guide covers other age-related changes, though Addison’s isn't limited to older dogs.

Your vet will start with your dog’s history, a physical exam, a blood count, a chemistry panel, electrolytes and usually a urinalysis. Findings that raise suspicion include low sodium, high potassium, a low sodium-to-potassium ratio, low blood sugar, and kidney values that shift with dehydration. Those findings suggest Addison’s. They don't confirm it.

Normal electrolytes don't rule it out. AAHA states that up to 25% to 30% of patients may have normal electrolytes, and that dogs with long-running or on-and-off signs may lack the classic changes. So, if your dog keeps having compatible signs, the vet may still check cortisol.

A resting cortisol level is often the first step. A high result makes Addison’s unlikely. AAHA’s diagnostic guidance says that when resting cortisol is below 2 micrograms per deciliter in a compatible case, an ACTH stimulation test should follow, because a low resting value alone isn't definitive.

The ACTH stimulation test measures cortisol before and after a dose of synthetic ACTH, and the Cornell Animal Health Diagnostic Center describes the protocol. A dog whose adrenal glands have little reserve shows a low or minimal response. Your vet reads the result. X-rays or ultrasound may be used to look for other causes of illness, but they don't replace the hormone test.

If your dog comes in during a crisis, hospital care usually starts with IV fluids. The team also corrects low blood sugar and dangerous electrolyte levels, gives injectable glucocorticoid replacement, treats nausea, offers nutritional support, and monitors blood pressure, electrolytes and heart rhythm, per the Merck Veterinary Manual. Dogs stay until circulation, hydration, electrolytes and blood sugar settle. The hospital team sets every dose, and this page gives none.

After that, treatment replaces what the adrenal glands can't make, and typical Addison’s generally needs it for life. Two hormone types may be replaced:

• Glucocorticoid replacement covers cortisol. Your vet may choose prednisone, prednisolone or another glucocorticoid.
• Mineralocorticoid replacement covers aldosterone. Options are an injectable called DOCP (desoxycorticosterone pivalate) or an oral medicine such as fludrocortisone. Some dogs get an oral medicine with both kinds of activity.

Injection or tablet is a choice your vet makes for your dog, based on how your dog responds and what the bloodwork shows. Not every dog needs the same combination. Dogs with atypical disease can still need electrolyte checks, because aldosterone deficiency can show up later.

Rechecks matter. A Spanish client handout from the LatinX Veterinary Medical Association says the first recheck is typically 1 to 2 weeks after discharge, and stable dogs may be seen every 4 to 12 months depending on the medication and response. Your vet sets your dog’s actual schedule.

Most of it comes down to routine and to keeping your vet in the loop.

For boarding or a pet sitter, hand over written instructions and your regular vet’s contact details. You can find veterinarians and emergency vets in our directory, and keep an emergency clinic’s number saved before you need it.

Side effects and undertreatment can look alike at first. Too much treatment may show up as changes such as extra thirst or urination. Too little may bring back the original weakness, vomiting or poor appetite. Report either to your vet and let them decide.

The outlook is better than the diagnosis sounds. Cornell reports that stabilized dogs generally have a very good outcome with continued treatment and monitoring, and veterinary reviews describe the long-term prognosis as good to excellent when the disease is found, treated and monitored. The main risks are missed treatment, too little monitoring, trouble during illness or stress, and a crisis that isn't treated quickly.

Two studies put numbers on it. A retrospective study on the PubMed Central archive looked at dogs with spontaneous hypoadrenocorticism, starting with 125 dogs and using 57 for survival analysis. Median survival after diagnosis was 5.6 years (95% confidence interval 4.1 to 7.1 years), and the estimated median age at death was 11.5 years. That describes that group of dogs. It doesn't promise a timeline for yours.

The 2022 owner survey in Veterinary Record asked about 308 dogs. Owners said the disease didn't affect quality of life in 29% of dogs, affected it sometimes in 43%, and affected it most of the time in 15%. These are owner-reported answers, not a treatment trial.

Ask your vet what outlook fits your dog, since age, other health problems and how steadily treatment is given all matter.

Cost depends on where you live, how big your dog is, whether there was an emergency, how long a hospital stay lasts, and which medicines are chosen. Figures below come from two cost-guide websites, accessed in September 2026, and they are estimates, not fee schedules.

Ask the clinic or emergency hospital for a written estimate covering the exam, bloodwork, ACTH test, monitoring, hospitalization and medicines. If the cost of long-term care worries you, our pet insurance article explains how chronic conditions and pre-existing conditions are treated.

Questions worth bringing to the visit:

• Is my dog’s disease typical or atypical?
• Has the ACTH test been done, and what did it show?
• What signs mean the emergency clinic, and what should I tell them?
• Which medicines will my dog take, in what form, and what happens if a dose is missed or vomited?
• When are the rechecks, and what will they cost?
• How do we plan for stress, travel, boarding and grooming?
• What should be on my dog’s medical ID?

The short answers below add to the sections above.

Many treated dogs do well for years. In the 57-dog survival group, the median was 5.6 years after diagnosis, and Cornell describes a very good outcome with continued treatment. Your vet can tell you what to expect for your dog.

You can't tell from signs alone, because they overlap with many illnesses. A vet confirms it with bloodwork and an ACTH stimulation test. Compatible signs that keep coming back are a reason to book a visit.

Give medicine exactly as prescribed, keep up rechecks, and tell your vet before stressful events. Know your emergency plan and keep a medical ID on your dog. Never change doses on your own.

Any dog can get it, with a middle-age pattern and an inconsistently reported tendency in females. Some breeds, including Standard Poodles, Portuguese Water Dogs and Great Danes, are overrepresented, which points to a hereditary contribution in some lines.

No. Addison’s is too little adrenal hormone, and Cushing’s is too much cortisol. Each has its own testing and treatment, and the Cushing’s disease article covers the other one.

If your dog is having an emergency sign today, go to the nearest emergency clinic. If the signs are milder but keep returning, call your vet this week and describe the pattern, including the good days. If your dog already has the diagnosis, write down your vet’s emergency instructions, set up a medical ID, and save your clinic’s and an emergency clinic’s numbers where you can find them fast. You don't have to learn all of this at once, and your vet is your guide on every medication question. I'm glad you're looking out for your dog.

• American Animal Hospital Association: AAHA’s 2023 guidelines
• American Animal Hospital Association: AAHA’s diagnostic guidance
• bvajournals.onlinelibrary.wiley.com: Veterinary Record
• Cornell University College of Veterinary Medicine: Cornell Animal Health Diagnostic Center
• Cornell University College of Veterinary Medicine: Cornell University College of Veterinary Medicine
• latinxvma.org: LatinX Veterinary Medical Association
• Merck Veterinary Manual: Merck Veterinary Manual
• PubMed Central: PubMed Central
• realvetcost.com: Real Vet Cost
• vetcostguide.com: VetCostGuide