Cushing’s disease, also called hyperadrenocorticism, is a hormone disease in which the body has too much of the steroid hormone cortisol in the blood for a long time. The University of Minnesota dermatology handbook describes it as a common hormone (endocrine) disease of dogs [1]. Most natural cases come from a small tumor in the pituitary gland at the base of the brain; a smaller share come from a tumor of an adrenal gland [1]. Long-term steroid medicine can also cause a form of it [1]. Hair loss, thin skin and repeat skin infections are among the signs owners notice most [1].
If your dog’s skin is getting thin, bruises easily or the coat is thinning, see your vet. Other diseases can cause the same signs.
For other reasons dogs lose hair, see hair loss in dogs.
Skin signs of Cushing’s disease
The handbook lists these skin and coat changes in dogs with the disease [1]:
- hair loss on both sides of the body in a matching pattern, usually without redness or itch, that tends to leave the head and lower legs alone;
- thin skin that loses its stretch, so folds may stay put and stretch marks can appear;
- blood vessels on the belly that are easy to see through the thin skin;
- blackheads (comedones), often along the belly;
- darker patches of skin (hyperpigmentation);
- bruising that happens easily;
- wounds that heal slowly, and sores over pressure points such as elbows and hocks;
- fine, dry scale (dry seborrhea);
- bacterial skin infections that keep coming back (pyoderma);
- firm, raised plaques caused by calcium deposits in the skin, often on the neck, belly or groin. For more on this, see calcinosis cutis in dogs.
Less often, demodectic mange or ringworm starts in an adult dog with the disease [1].
Signs beyond the skin
Owners often see their dog drinking and urinating more, eating more, panting at rest and developing a potbelly [1]. Tiredness, muscle weakness and less interest in exercise are also common, because extra cortisol breaks down muscle [1].
Which dogs get it
The natural form is a disease of middle-aged and older dogs, usually over 6 years of age, and most affected dogs are older than 9 [1]. Males and females are affected alike [1]. The handbook names Poodles, Dachshunds, Beagles, Boxers, Boston Terriers and German Shepherds among the breeds seen most often [1]. The form caused by steroid medicine can happen at any age and in any breed [1].
How vets diagnose it
Many other illnesses, such as kidney, liver or thyroid disease and diabetes, cause signs that overlap with Cushing’s disease, so vets check for them first [1]. The diagnosis rests on the dog’s history and signs together with blood and urine tests and special hormone tests [1]. No hormone test is right every time, and dogs with other diseases can test positive [1]. Your vet will explain which tests your dog needs.
Treatment
Your vet will advise on treatment for your dog.
At home, as directed by a vet:
- do not give your dog human or leftover medicines or supplements unless your vet says so;
- do not stop or change any medicine without talking to your vet;
- give any treatment exactly as your vet prescribes;
- go back for any recheck or test your vet books.
When to see your vet
See your vet if your dog has:
- hair loss, thin skin, blackheads or bruising [1];
- darker skin, slow-healing wounds or skin infections that keep returning [1];
- drinking and urinating more, a bigger appetite, a potbelly or panting [1];
- any skin or coat change you are unsure about.
The bottom line
Cushing’s disease is a hormone disease of adult and older dogs that can change the skin and coat. Only a vet can tell it apart from other causes of hair loss and skin change.
This article is for general information only and does not replace advice from your veterinarian. If your dog’s skin or coat is changing, see your vet.
Sources
- Torres SMF. 1.2 Hyperadrenocorticism: Canine. Small and Large Animal Dermatology Handbook, Vol. 2. University of Minnesota, 2025. CC BY 4.0. https://open.lib.umn.edu/animaldermatology2/chapter/hyperadrenocorticism-canine/