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
Understanding supports better veterinary conversations.
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.
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.
Which animals can be affected?
Risk factors, examination findings and management can 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.
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.
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.
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 emergency veterinary care if you notice:
SEEK EMERGENCY VETERINARY 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.
Sources behind this guide
Cornell University: Addison’s diseasePrimary veterinary or veterinary-university guidance ↗American Animal Hospital Association: canine Addison’s overviewPrimary veterinary or veterinary-university guidance ↗American Animal Hospital Association: diagnostic testingPrimary veterinary or veterinary-university guidance ↗American Animal Hospital Association: hormone replacement and monitoringPrimary veterinary or veterinary-university guidance ↗Content last reviewed: August 30, 2026. Review status: veterinary-informed; independent veterinarian review not yet completed.