DOGS · OWNER EDUCATION
Addison’s Disease: Too Little Cortisol
A plain-language guide to a hormone shortage that can cause recurring stomach upset and weakness, including Addisonian crises and lifelong care.
THE SHORT VERSION
What matters for your animal?
Start with the warning signs and when-to-contact sections if your animal is unwell. The same outward change can have several causes, so this guide helps you prepare questions rather than identify a diagnosis on your own.
What is this condition?
Addison’s disease, or hypoadrenocorticism, means the adrenal glands do not supply enough essential hormones. Cortisol supports energy use and the response to stress. Aldosterone helps regulate salt, water balance and blood pressure. Dogs may lack cortisol alone or both hormones. Unlike Cushing’s, this is a shortage—not an excess—of cortisol.
Addison's disease is a shortage of adrenal hormones, and its signs may fluctuate or resemble digestive illness. A crisis can affect circulation and internal balance, requiring emergency stabilization. Long-term replacement and monitoring address a different task: keeping the animal stable between episodes. Ask for written instructions about illness, stress, missed medication, and when the usual daily plan needs veterinary reassessment.
Hormones are chemical signals that help coordinate functions such as energy use, stress responses, water balance, and reproduction. A shortage or excess may affect several body systems at once, which is why a hormone disorder can resemble other illnesses. Routine bloodwork may show effects of the disorder without confirming its cause. More specific testing may be needed, and illness or medication can influence some results. Monitoring follows both how the animal feels and what the appropriate tests show.
Digestive signs describe what the animal is doing, rather than a single disease. The problem may be in the digestive tract itself or may reflect pain, metabolic illness, toxins, or another body-wide condition. Fluid loss and reduced food intake can become important complications even before the exact cause is confirmed. The investigation considers the timeline, diet, access to foreign material, stool output, and other signs. This helps distinguish a problem that may respond to medical support from one that needs urgent intervention.
Which species does this guide cover?
The species listed above are the focus of this guide, rather than a complete list of every animal that can develop this condition. Causes, testing and treatment may differ between species and individual patients.
Why can it happen?
- The immune system often damages the adrenal glands. This is not caused by an owner failing to keep a dog calm.
- Less commonly, problems with hormone signals or medication effects cause cortisol deficiency. Suddenly stopping long-term steroids or excessive suppression during Cushing’s treatment can be dangerous.
- Dogs of any breed or age can be affected. This article explains canine care; other species need their own veterinary assessment.
What might an owner notice?
- Poor appetite, vomiting, diarrhea, tiredness, weight loss, shaking or weakness.
- A dog may seem better for a while and then become ill again. These signs also occur with many digestive and other diseases.
- Some dogs have normal sodium and potassium results, sometimes called ‘atypical’ Addison’s. Normal electrolytes do not rule it out.
How is the problem investigated?
Bloodwork and urine testing check hydration, organ function and electrolytes such as sodium and potassium. An electrolyte pattern can raise suspicion but cannot confirm the disease. A resting cortisol test can help rule Addison’s out. A low result alone does not prove it; many dogs with a low resting cortisol do not have Addison’s. Confirmation usually requires an adrenocorticotropic hormone (ACTH) stimulation test: blood is sampled before and after a hormone signal to see whether the adrenal glands can make cortisol. Tell the clinic about all medicines, especially steroids, because they can affect testing. An unstable dog needs urgent treatment, not a delay while an owner tries to interpret results.
Blood-cell testing and a chemistry profile provide complementary information. Cell counts can help assess anemia, inflammation, and platelets; chemistry measurements help assess organs and internal balance. Results are interpreted against the species, examination, hydration, medication history, and previous values. A value just outside the reference interval is not automatically the cause of illness. Trends can be more useful than one result, particularly when the aim is to monitor a chronic problem or check that treatment remains safe.
What might treatment involve?
An Addisonian crisis is a hospital emergency. Treatment may include intravenous fluids, steroid replacement and correction of dangerous electrolyte or blood-sugar changes. Long-term care replaces missing hormones. A daily prescribed steroid replaces cortisol. Dogs needing salt-balance hormone replacement may receive desoxycorticosterone pivalate (DOCP) injections or an oral alternative such as fludrocortisone. Treatment is usually lifelong. The veterinarian tailors doses and injection intervals using the dog’s condition and repeat blood tests.
Fluid treatment is tailored to the cause of fluid loss, circulation, electrolytes, and organ function. Drinking some water does not prove that an animal has corrected a significant deficit. Conversely, giving more fluid is not always safer, especially when certain heart or kidney problems are present. The team may need to monitor body weight, urine output, breathing, and blood values while providing support. Home fluid administration should only follow a specific veterinary plan with practical instruction and a reassessment schedule.
This is an overview, not a prescription or a recommendation for a specific individual animal.
What can owners do at home?
Keep medication and appointment records; arrange refills before supplies run out. Ask for a written stress-dose plan for illness, boarding, travel or surgery. Some dogs need a temporary prescribed steroid increase; do not invent the adjustment yourself. Ask what to do if a dose is missed or vomited, and keep emergency contact information with the medication list. Monitor appetite, energy, stool, weight, thirst and urination. Report changes even when the dog initially seems well after treatment.
Avoid actions that could make care less safe.
- Do not stop replacement hormones because the dog looks better, skip monitoring or change doses without the veterinary plan.
- Do not try to treat a crisis with food, salt, sports drinks or leftover medicines.
- Do not wait for every textbook sign to appear before seeking help.
What can the longer-term outlook involve?
After stabilization, many dogs do very well with consistent replacement hormones and monitoring. A crisis is serious, but a diagnosis does not automatically mean a poor long-term quality of life.
A recheck is not simply a repeat of the first appointment. It assesses whether the original problem is improving, whether complications are appearing, and whether the treatment remains appropriate. The useful measures may include comfort, function, intake, body weight, examination findings, or selected tests. Ask which changes are expected before the visit and which should trigger an earlier call. Improvement in one sign does not always mean that every part of the disease has resolved.
Can risk be reduced?
Most naturally occurring cases cannot be prevented. Reliable treatment and an individualized illness/stress plan help reduce future crises.
When should you arrange care?
- Arrange evaluation for recurring stomach upset, unexplained weight loss or weakness.
- For a diagnosed dog, call promptly about reduced appetite, vomiting, diarrhea, unusual tiredness or difficulty giving medication.
Seek urgent veterinary advice if you notice:
DO NOT DELAY URGENT CARE- Sudden collapse, inability to stand, profound weakness or reduced responsiveness.
- Severe or repeated vomiting or diarrhea with weakness or dehydration can be an Addisonian crisis. Go to an emergency hospital; tell staff about Addison’s or possible steroid/cortisol-lowering medication exposure.
What information helps the care team?
Write down when changes started, what makes them better or worse, actual food and water intake, and all medicines and supplements. Short videos and a medication-label photo can help describe changes that may not appear during the appointment.
How should you understand the tests?
Ask what each proposed test is intended to answer. Some tests identify a cause; others assess severity, organ function or treatment safety. Results are interpreted with the examination and history. A normal result does not exclude every problem, and an abnormal result does not always explain every sign.
Questions to ask before leaving
- What is confirmed, and which other explanations are still being considered?
- What changes should we expect with the proposed plan, and when should we reassess if they do not occur?
- Which observations should I record, and which changes mean I should call sooner?
- What medicine or home-care problems should I report, and what are the instructions for a missed dose or suspected side effect?
- When is the recheck, what will it assess, and whom should I contact after hours?
A care plan may be adjusted as results or the response become clearer. Keep the written instructions and tell the team if cost, handling or administration difficulty makes the plan hard to follow.
Sources behind this guide
Cornell University: Addison’s diseaseVeterinary, university or animal-health guidance ↗American Animal Hospital Association: canine Addison’s overviewVeterinary, university or animal-health guidance ↗American Animal Hospital Association: diagnostic testingVeterinary, university or animal-health guidance ↗American Animal Hospital Association: hormone replacement and monitoringVeterinary, university or animal-health guidance ↗Content last reviewed: August 30, 2026. Review status: veterinary-informed; independent veterinarian review not yet completed.