Cushing's disease

Cushing's disease, or hyperadrenocorticism, is too much cortisol. It occurs mainly in middle-aged and older dogs; the pituitary form is seen mostly in small breeds and adrenal tumours more often in larger dogs¹. In UK practices roughly 0.2 to 0.3 percent of dogs carried the diagnosis, with the Bichon Frise, Border Terrier and Miniature Schnauzer at the highest odds and the Golden Retriever and Labrador Retriever among the least affected; odds rose with age and with weight above the breed average²³.

The picture is distinctive once you know it: drinking and urinating a lot, a big appetite, a pot belly, panting, muscle wasting, thinning skin and symmetrical hair loss, and repeated skin or urinary infections¹. Because the disease also worsens diabetes, pancreatitis and dental disease, it is worth pursuing rather than accepting as old age.

Testing is a series of blood tests and often an ultrasound. AAHA's 2023 endocrine guidelines set out diagnosis and treatment, which is usually a daily drug that lowers cortisol, with regular monitoring⁴. Dogs on treatment can feel very well for years.

This is general information, not a diagnosis. Your vet knows your dog.

Sources

1. Cushing Syndrome (Hyperadrenocorticism) in Animals. Merck Veterinary Manual. Accessed 2026-09-22.
2. Epidemiology of hyperadrenocorticism among 210,824 dogs attending primary-care veterinary practices in the UK from 2009 to 2014 (O'Neill DG et al.). Journal of Small Animal Practice 57(7):365-373, 2016 (peer reviewed). Accessed 2026-09-22.
3. Frequency and risk factors for naturally occurring Cushing's syndrome in dogs attending UK primary-care practices (Schofield I et al.). Journal of Small Animal Practice 63(4):265-274, 2022 (peer reviewed). Accessed 2026-09-22.
4. 2023 AAHA Selected Endocrinopathies of Dogs and Cats Guidelines. American Animal Hospital Association, Journal of the American Animal Hospital Association 59(3):113-135. Accessed 2026-09-22.