Cushing's Disease and Skin Problems in Dogs

By Emiel Maddens  ·  Reviewed in consultation with licensed veterinary professionals  ·  Updated June 2026  ·  10 min read

Photo by Anya Prygunova on Unsplash

Cushing's disease, known in veterinary medicine as hyperadrenocorticism, is one of the most common endocrine disorders in middle-aged and older dogs. The condition occurs when the adrenal glands produce excessive amounts of cortisol, a stress hormone that, in normal quantities, regulates metabolism, immune function, and inflammation. When cortisol levels remain chronically elevated, virtually every organ system suffers, but the skin is often the first and most visibly affected tissue.

Many dog owners initially bring their pet to the veterinarian for what appears to be a stubborn skin problem, only to discover that the real culprit is a hormonal imbalance. Hair that falls out and never regrows, skin that tears like tissue paper, and infections that return within days of finishing antibiotics are all red flags that point beyond ordinary dermatitis. Understanding the connection between Cushing's disease and skin health is essential for recognizing this condition early and pursuing effective treatment.

This guide explains how excess cortisol damages canine skin, what the characteristic dermatological signs look like, how veterinarians diagnose and treat the condition, and what you can do at home to support your dog's skin while the underlying hormonal disorder is brought under control.

How Cushing's Disease Develops in Dogs

Hyperadrenocorticism in dogs takes three primary forms. Pituitary-dependent Cushing's disease accounts for roughly 80 to 85 percent of cases and arises when a small, typically benign tumor in the pituitary gland secretes excessive adrenocorticotropic hormone (ACTH). This hormone signals the adrenal glands to ramp up cortisol production far beyond what the body needs. Adrenal-dependent Cushing's disease, representing about 15 to 20 percent of cases, occurs when a tumor grows directly on one of the adrenal glands and autonomously produces cortisol independent of ACTH signaling.

Iatrogenic Cushing's Syndrome

A third form, iatrogenic Cushing's syndrome, develops when dogs receive corticosteroid medications such as prednisone, dexamethasone, or topical steroid preparations for prolonged periods. The external steroids mimic the effects of endogenous cortisol, creating the same spectrum of clinical signs. This form is fully reversible when the exogenous steroids are gradually tapered and discontinued under veterinary supervision.

Certain breeds face heightened risk for naturally occurring Cushing's disease. Poodles, Dachshunds, Boston Terriers, Boxers, and Beagles are overrepresented in clinical studies. Most dogs are diagnosed between 6 and 12 years of age, though the condition can develop earlier in predisposed breeds. Because cortisol affects nearly every tissue, the signs are often diffuse and can masquerade as normal aging for months before the true diagnosis is reached.

Why Excess Cortisol Destroys Skin Health

Cortisol is a powerful catabolic hormone. At normal physiological levels it helps regulate glucose metabolism and suppress excessive inflammation. At chronically elevated levels, however, cortisol breaks down collagen and elastin, the structural proteins that give skin its strength and elasticity. The dermis becomes progressively thinner, blood vessels lose their support scaffolding and become fragile, and the epidermis loses its barrier integrity.

Hair Follicle Arrest

Cortisol also directly inhibits the hair growth cycle. Hair follicles are pushed into a prolonged resting phase called telogen and are unable to re-enter the active growth phase (anagen). The result is progressive, often symmetrical hair loss that typically begins on the flanks and trunk and spares the head and extremities. Once follicles enter this cortisol-induced arrest, hair will not regrow until cortisol levels are normalized.

Immune Suppression and Secondary Infections

Perhaps the most clinically significant dermatological consequence of elevated cortisol is immune suppression. Cortisol dampens the activity of neutrophils, macrophages, and lymphocytes, the white blood cells responsible for fighting bacterial and fungal invaders. Dogs with Cushing's disease are predisposed to recurrent superficial bacterial pyoderma, Malassezia yeast dermatitis, and even demodectic mange, because the immune system can no longer keep commensal organisms in check.

Cortisol also stimulates the sebaceous glands to produce more oil while simultaneously impairing the turnover of surface skin cells. This combination creates an environment that favors microbial overgrowth. Many Cushing's patients develop a greasy coat, follicular plugging (comedones), and a distinctive musty odor from concurrent yeast colonization.

Symmetrical hair loss on the trunk is one of the most recognizable skin signs of Cushing's disease in dogs.

Photo by Alexander Mass on Unsplash

Recognizing Cushing's-Related Skin Changes

Symmetrical Alopecia

The most recognizable skin sign of Cushing's disease is bilateral symmetrical alopecia. Hair loss typically begins on the flanks, abdomen, and perineal region and gradually spreads to the chest and back. The head and distal limbs are usually the last areas affected. Unlike allergic hair loss, Cushing's alopecia is not itchy in itself, though secondary infections can introduce pruritus.

Thin, Fragile Skin

Dermal atrophy is a hallmark of chronic cortisol excess. The skin becomes visibly thin, sometimes to the point where underlying blood vessels are easily seen through the surface. Bruising occurs with minimal trauma, and wounds heal slowly. In severe cases the skin can tear during routine handling, grooming, or even from the adhesive of a bandage.

Calcinosis Cutis

Calcinosis cutis refers to the deposition of calcium salts within the skin. It appears as firm, white-to-yellowish plaques or nodules, often on the dorsal neck, groin, and axillae. These lesions can ulcerate, become secondarily infected, and cause significant discomfort. Calcinosis cutis is strongly associated with Cushing's disease and iatrogenic steroid use, making it an important diagnostic clue.

Comedones and Hyperpigmentation

Comedones, or blackheads, develop when hair follicles become plugged with keratin and sebum under the influence of excess cortisol. They commonly appear on the ventral abdomen. Hyperpigmentation, a darkening of the skin, often accompanies chronic inflammation and hormonal disruption and tends to be most prominent in areas of hair loss.

Pot-Bellied Appearance

While not strictly a skin finding, the pot-bellied appearance seen in many Cushing's patients contributes to the overall clinical picture. Cortisol redistributes fat to the abdomen, weakens abdominal muscles, and enlarges the liver (hepatomegaly), all of which combine to produce a pendulous, distended belly that stretches the already-thinned abdominal skin.

Diagnosing Cushing's Disease: The Testing Pathway

Diagnosing hyperadrenocorticism requires a combination of clinical suspicion, routine laboratory work, and specific endocrine testing. Routine bloodwork often reveals elevated alkaline phosphatase (ALP), a stress leukogram with neutrophilia and lymphopenia, elevated cholesterol, and dilute urine with a specific gravity below 1.020. These findings are suggestive but not definitive.

ACTH Stimulation Test

The ACTH stimulation test measures the adrenal glands' response to synthetic ACTH. A baseline cortisol sample is drawn, synthetic ACTH is administered intravenously, and a post-stimulation sample is collected one hour later. An exaggerated cortisol response supports a diagnosis of Cushing's disease. This test is especially useful for monitoring treatment response and is the preferred screening test for iatrogenic Cushing's.

Low-Dose Dexamethasone Suppression Test

The low-dose dexamethasone suppression test (LDDS) is considered the most sensitive screening test for naturally occurring Cushing's. A baseline cortisol level is drawn, a low dose of dexamethasone is administered, and cortisol levels are measured at four and eight hours. In a healthy dog, dexamethasone suppresses cortisol production. In a Cushing's patient, cortisol remains elevated because the normal feedback mechanism is disrupted.

Abdominal Ultrasound

Abdominal ultrasound plays a critical role in differentiating pituitary-dependent from adrenal-dependent disease. Bilateral adrenal enlargement suggests pituitary-dependent Cushing's, while a unilateral adrenal mass with atrophy of the opposite gland points to an adrenal tumor. Ultrasound also evaluates the liver, which is commonly enlarged in Cushing's patients.

Treating Cushing's Disease and Restoring Skin Health

Trilostane Therapy

Trilostane (Vetoryl) is the most commonly prescribed medication for pituitary-dependent Cushing's disease. It works by inhibiting an enzyme called 3-beta-hydroxysteroid dehydrogenase, which is essential for cortisol synthesis in the adrenal glands. By reducing cortisol production, trilostane allows the skin to begin healing. Most dogs show improvement in energy and water intake within the first few weeks, but skin and coat changes take longer, often three to six months, to become fully apparent.

Surgical Options

For adrenal-dependent Cushing's disease, surgical removal of the affected adrenal gland (adrenalectomy) can be curative if the tumor has not metastasized. Pituitary surgery (transsphenoidal hypophysectomy) is available at select referral centers and can cure pituitary-dependent disease, though it carries significant anesthetic and surgical risks and requires lifelong hormone replacement.

Managing Secondary Skin Infections

While the underlying cortisol excess is being treated, secondary skin infections must be addressed concurrently. Bacterial pyoderma typically requires systemic antibiotics guided by culture and sensitivity testing, because chronic steroid exposure increases the risk of resistant organisms. Topical antiseptic therapy with chlorhexidine-based sprays or shampoos can help reduce bacterial and yeast loads on the skin surface between systemic treatments.

Skin Recovery Timeline

Once cortisol levels normalize, the skin begins a gradual recovery process. Hair regrowth is usually the slowest change, often taking four to eight months. Some dogs experience a temporary worsening of coat appearance as old telogen hairs are shed before new anagen hairs emerge. Calcinosis cutis lesions may soften and slowly resorb over several months, though severe deposits sometimes require surgical debridement.

Owners should expect regular veterinary rechecks during treatment, typically every two to four weeks initially, then every three to six months once the dog is stable. ACTH stimulation testing is used to monitor cortisol levels and adjust trilostane dosing as needed.

Home Care for Dogs with Cushing's Skin Problems

Supporting your dog's skin at home is an important complement to medical treatment. Gentle bathing with a veterinary-recommended antiseptic shampoo every one to two weeks helps reduce surface bacteria and yeast, clear comedones, and soothe irritated skin. Allow the shampoo to remain in contact with the skin for at least ten minutes before rinsing to maximize antimicrobial contact time.

Protecting Fragile Skin

Dogs with Cushing's-related dermal atrophy are prone to skin tears, so take precautions to minimize trauma. Use soft bedding, avoid rough play, and handle your dog gently during grooming. If your dog wears a harness, ensure it fits loosely and does not rub against thinned skin. Consider placing a light t-shirt over areas prone to contact injuries.

Nutrition and Supplements

While no diet cures Cushing's disease, feeding a high-quality, moderate-protein diet supports overall health during treatment. Omega-3 fatty acid supplementation (fish oil) may help reduce skin inflammation and support barrier function. Discuss appropriate dosing with your veterinarian, as the optimal dose depends on your dog's size and concurrent medications.

Monitor your dog's skin closely and photograph any new lesions, areas of hair loss, or changes in existing calcinosis cutis plaques. These photos provide valuable information for your veterinarian at recheck appointments and help track the trajectory of skin healing over time.

Cushing's Disease and Skin Problems in Dogs FAQ

Q: What are the first skin signs of Cushing's disease in dogs?

The earliest skin signs are usually symmetrical hair loss on the flanks and trunk, a thinning coat that fails to regrow after clipping, and recurrent skin infections that respond to antibiotics but return quickly. Many owners also notice increased skin oiliness and a pot-bellied appearance developing over the same time frame.

Q: Can Cushing's disease in dogs be cured?

Adrenal tumors can sometimes be cured with surgical removal if they have not spread. Pituitary-dependent Cushing's disease is more commonly managed medically with trilostane, which controls cortisol levels effectively but requires lifelong treatment and monitoring. Iatrogenic Cushing's resolves when the causative steroid medication is properly tapered.

Q: How long does it take for a dog's skin to improve after starting Cushing's treatment?

Most dogs show improvement in energy and thirst within the first two to four weeks of trilostane therapy. Skin improvements are slower, with reduced infection frequency often noticed within one to two months and hair regrowth typically beginning at three to six months. Full coat recovery can take six to twelve months.

Q: Is calcinosis cutis painful for dogs?

Calcinosis cutis can be uncomfortable, especially when the hard calcium deposits crack the overlying skin or become secondarily infected. Dogs may show sensitivity when the affected areas are touched. As Cushing's treatment normalizes cortisol levels, the deposits gradually soften and often resorb, though large or ulcerated lesions sometimes require surgical removal.

Q: Can I use over-the-counter skin products on my dog with Cushing's disease?

Avoid using human skin products, as many contain fragrances, alcohols, or ingredients that can irritate already-compromised canine skin. Veterinary-formulated topical antiseptics like chlorhexidine sprays are safe and effective for managing surface infections. Always consult your veterinarian before adding any topical product to your dog's care routine, especially given the fragility of Cushing's-affected skin.

Sources

Behrend EN, Kooistra HS, Nelson R, et al. Diagnosis of spontaneous canine hyperadrenocorticism: 2012 ACVIM consensus statement. Journal of Veterinary Internal Medicine. 2013;27(6):1292-1304.

Ramsey IK. Trilostane in dogs. Veterinary Clinics of North America: Small Animal Practice. 2010;40(2):269-283.

Zur G, White SD. Hyperadrenocorticism in 10 dogs with skin lesions as the only presenting complaint. Journal of the American Animal Hospital Association. 2011;47(6):419-427.

Beco L, Fontaine J, Bergvall K, Favrot C. Comparison of skin scraping and hair plucks for detecting Demodex mites in canine demodicosis, a multicentre, prospective study. Veterinary Dermatology. 2007;18(5):381.

Feldman EC, Nelson RW. Canine and Feline Endocrinology and Reproduction. 4th ed. St. Louis: Elsevier Saunders; 2015.

Related Reading

• Calcinosis Cutis in Dogs, a detailed look at calcium deposits under the skin and their connection to cortisol excess
• Dogs with Multiple Skin Conditions, how to manage overlapping dermatological problems in complex cases
• Chlorhexidine for Dogs, a complete guide to using topical antiseptics for canine skin infections
• Medicated Dog Shampoo Guide, choosing the right therapeutic shampoo for your dog's specific skin condition

Emiel Maddens

Founder of Vetified. Develops topical antifungal and antimicrobial formulations for companion animals. Vetified products are listed on DailyMed and manufactured through FDA-registered facilities in the United States.