Cushing's disease in dogs: recognising the signs and managing it well

Cushing's disease (hyperadrenocorticism) happens when the adrenal glands produce too much cortisol. It is most common in middle-aged and older dogs, particularly small breeds like Poodles, Dachshunds and Terriers, though any dog can be affected.

The signs build slowly, which is why owners often miss them at first: increased thirst and urination, a ravenous appetite, a sagging 'pot-bellied' abdomen, thinning skin and hair loss, panting, and reduced energy. Some dogs develop recurrent skin or urinary infections.

There are two main forms. Pituitary-dependent Cushing's (a small benign tumour on the pituitary that over-stimulates the adrenals) accounts for most cases, while adrenal tumours make up the rest. Distinguishing them matters because the treatment and prognosis differ.

Diagnosis is not a single test. A screening blood panel, a urine cortisol:creatinine ratio, and then a low-dose dexamethasone suppression or ACTH stimulation test are typical. Imaging (ultrasound or CT) helps locate the source. Your vet will sequence these rather than run everything at once.

Most pituitary cases are managed medically with trilostane, which blocks cortisol production. It is given daily for life, with monitoring blood tests every few weeks initially and then every few months. With good control, many dogs live a normal lifespan.

Adrenal tumours may be surgical if they are operable and have not spread. Your vet will discuss referral to a specialist surgeon if that is the right path.

Untreated, Cushing's slowly erodes quality of life — skin breaks down, infections recur, muscles weaken. Treated, the changes are often reversible within weeks. If your older dog is drinking and eating far more than usual and losing their shape, ask for bloodwork rather than putting it down to age.