Cushing’s disease in dogs

Cushing’s syndrome happens when your dog’s body makes too much of a hormone called cortisol. This hormone usually helps your dog respond to stress, controls his weight, fights infections, and keeps his blood sugar levels in check but when there is too much, or too little of it, problems occur.

Cushing’s, which is also known as hypercortisolism and hyperadrenocorticism, can be tricky for a vet to diagnose, because it has the same symptoms as other conditions. It can look similar to diabetes so it is important to take your dog to the vet if he is suddenly eating or drinking a lot.

Cushing’s mostly affects middle-aged and older dogs, and the warning signs may be harder to spot in the beginning.

Cushing’s symptoms to look out for

  • Your dog is gaining weight
  • Your dog is always hungry; eats everything in sight, and even digs for food in the garbage
  • Drinks a lot more water than usual
  • Pees more often; housebroken dogs may even have indoor accidents
  • Loses hair on his tail or in a symmetrical pattern on his body
  • Develops a pot belly
  • Has thinning skin
  • Seems very tired and inactive
  • Pants a lot
  • Is prone to skin infections

Types of Cushing’s Syndrome

Many animals can get this condition. People can get it too. There are two major types that affect dogs:

  •  Pituitary dependent. This form is the most common, affecting about 80% to 90% of the animals who have Cushing’s. It happens when there’s a tumour in a pea-sized gland called the pituitary at the base of the brain.
  •  Adrenal dependent. This type comes from a tumour in one of the glands that sit on top of the kidneys. These are called adrenal glands. About 15% of diagnosed dogs will have this type.

Another kind, called iatrogenic Cushing’s syndrome, happens after a dog has taken steroids for a long time.

How it is diagnosed

There’s no method that’s 100% accurate for diagnosing Cushing’s so your vet will do a few tests to see what may be causing your pet’s symptoms, and to rule out other health problems.

Your vet will test your dog’s blood and their pee. These exams can detect diluted urine, urinary tract infections or problems with a group of enzymes mostly found in the liver and bones called alkaline phosphatase. All of these are common in animals with Cushing’s. If the results show signs of the condition, your vet will follow up with hormone screening tests, such as:

  •  ACTH stimulation test. It measures how well the adrenal glands work in response to a hormone called ACTH that usually prompts them to make cortisol. The vet will take blood samples before and after your dog gets a shot of ACTH to see how the hormone affected them.
  •  Low dose dexamethasone suppression (LDDS) test looks at how your dog’s body works with a man-made version of cortisol, called dexamethasone.
  • Blood samples before and after they get a shot of the hormone help the vet see what’s going on.

If it seems like your dog could have Cushing’s, your vet might want to do an ultrasound scan of his belly. This imaging test will help to identify if there’s a tumour on the adrenal glands. That could affect the kind of treatment they need.


If Cushing’s syndrome comes from a tumour on your pet’s adrenal glands, the vet might be able to remove it with surgery, which will cure him of the problem. But if the tumour has spread to other parts of their body or they have other health problems, surgery may not be an option.

Usually, a dog can live an active, normal life on medication, though they’ll need it for the rest of their life. Drugs are best for dogs with Cushing’s syndrome caused by the pituitary gland or for those with a tumour on their adrenal gland that can’t be removed with surgery.

Your dog will need regular check-ups and blood tests to make sure their treatment is working.

If your pet has iatrogenic Cushing’s syndrome, your vet can try to gradually stop giving them steroids. But the original condition they were treating will probably come back.

The most important thing you can do is to follow your dog’s treatment plan. Keep a close watch on their behaviour and symptoms, and give them the right medication doses at the right times. You and your vet can work together to help them live a happy, healthy life.


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