🐶 Cushing’s Disease in Dogs – A Vet’s Complete 2025 Guide to Diagnosis and Treatment

By Dr Duncan Houston, BVSc

🧠 What Is Cushing’s Disease (Hyperadrenocorticism)?

Cushing’s disease—also known as hyperadrenocorticism—is a hormonal disorder caused by the overproduction of cortisol in dogs. Cortisol is a vital hormone that helps regulate metabolism, immune response, blood pressure, and more. However, too much of it causes significant health issues. 🧬💥

This condition is most often seen in middle-aged to older dogs, and if left untreated, it can drastically affect their quality of life. Fortunately, with timely diagnosis and proper management, dogs with Cushing’s can continue to live happy and active lives. 🐾❤️

🏥 Causes of Cushing’s Disease

Cushing’s disease arises from different types of abnormalities in the body’s hormone-regulating glands:

• Pituitary-Dependent Cushing’s Disease 🧠 – The most common form (85–90% of cases). A benign tumor in the pituitary gland causes overproduction of adrenocorticotropic hormone (ACTH), which stimulates the adrenal glands to produce excess cortisol.
• Adrenal-Dependent Cushing’s Disease ⚖️ – Caused by a tumor in one of the adrenal glands, located near the kidneys. These tumors may be benign or malignant.

Both forms result in excess cortisol, but identifying the exact cause helps determine the right treatment plan. 🩺

🔍 Clinical Signs of Cushing’s Disease in Dogs

Dogs with Cushing’s often exhibit a wide range of signs, many of which develop gradually. Watch for these common symptoms:

• 🚰 Increased thirst and urination
• 🍗 Ravenous appetite
• 🍩 Pot-bellied appearance (abdominal enlargement)
• 🐾 Hair thinning or hair loss
• 💤 Lethargy or decreased activity
• 🐶 Panting without exertion
• 🔁 Recurring skin or ear infections

Because these signs overlap with other diseases, diagnosing Cushing’s can be tricky, especially in the early stages. 🧩

🧪 Diagnosing Cushing’s Disease

A multi-step process involving blood tests and imaging is often needed. Here are the primary diagnostic tools:

📋 Initial Tests

• Complete Blood Count (CBC)
• Biochemistry Panel
• Urinalysis

These tests help identify general health trends and rule out other diseases. Common findings in dogs with Cushing’s may include elevated liver enzymes, dilute urine, and high cholesterol. 🧾

💉 Hormone-Specific Tests

• ACTH Stimulation Test – A blood test before and after administering ACTH hormone. Helps confirm cortisol overproduction.
• Low-Dose Dexamethasone Suppression Test (LDDST) – Monitors how your dog’s cortisol levels respond over 8 hours after receiving a steroid injection.
• High-Dose Dexamethasone Suppression Test (HDDST) – Differentiates between pituitary and adrenal causes when needed.
• Endogenous ACTH Assay – Measures ACTH levels to help locate the root cause (pituitary vs adrenal).

🖥️ Imaging Studies

• Abdominal Ultrasound – To examine adrenal glands for tumors or enlargement
• X-rays or CT Scans – Help evaluate internal organs or identify tumors

Confirming a diagnosis often requires combining hormone testing with imaging for the most accurate results. 🎯

💊 Treatment Options for Cushing’s Disease

Treatment depends on the underlying cause. Here are the most common approaches: 🔬

1. 🧪 Medication (Medical Management)

Most cases, especially pituitary-dependent, are treated with medication to reduce cortisol levels:

• Trilostane (Vetoryl®) – The most commonly prescribed drug. It inhibits cortisol production and is administered daily. 🐶💊
• Mitotane (Lysodren®) – An older drug that destroys adrenal tissue to reduce hormone levels. It’s more aggressive and requires close monitoring. 🔥

2. 🔪 Surgery

• Adrenalectomy – Surgical removal of an adrenal tumor in adrenal-dependent cases. This is major surgery and is typically performed by a specialist. 🏥

3. 🚫 Radiation Therapy

Used in rare cases of pituitary macroadenomas (larger tumors). This may shrink the tumor and alleviate neurological symptoms. 🧲

📅 Monitoring and Long-Term Care

Dogs receiving treatment for Cushing’s require lifelong monitoring. Regular bloodwork and hormone testing are essential to adjust medication doses and watch for side effects. 📈

Typical Follow-Up Schedule:

• ACTH stimulation test every 2–4 weeks during initial treatment 🔄
• Every 3–6 months thereafter to ensure stable control ✅
• Periodic blood pressure checks and urinalysis 🩸

📲 Ask A Vet: Support for Cushing's Disease

Caring for a dog with Cushing’s can feel overwhelming, but with professional guidance and a consistent care routine, your dog can live a vibrant life. 🐕✨

Need help managing medications or test results? Download the Ask A Vet App or visit AskAVet.com for expert advice, reminders, and support from licensed veterinarians—available when you need it. 📱🩺

✅ Key Takeaways

• Cushing’s disease is caused by excess cortisol production 🧠
• Symptoms include thirst, appetite, hair loss, and weight gain 🚰🍖
• Diagnosis requires multiple tests and imaging 📋🧪
• Treatment includes daily medication or surgery 💊🏥
• Long-term monitoring is essential for success 📆🔬

🐾 Final Thoughts from Dr Duncan Houston

Cushing’s disease is complex, but highly manageable. With the right diagnosis, treatment plan, and support, most dogs go on to enjoy many more years of happy, healthy life. 🐶❤️

For all your pet care needs, from Cushing’s disease to routine wellness, the Ask A Vet App is your go-to resource for 2025 and beyond. Tap into expert care today at AskAVet.com. 🐾📲