Cushing’s Disease (PPID) in Horses 2025: Vet‑Approved Diagnosis, Treatment & Management

By Dr Duncan Houston BVSc 🩺

Pituitary Pars Intermedia Dysfunction (PPID), also known as equine Cushing’s disease, is the most common endocrine disorder in senior horses. With up to 20–30% affected by age 15–20, understanding the latest diagnostics, treatments, dietary strategies, and long‑term care has never been more important :contentReference[oaicite:3]{index=3}. This guide gives you evidence‑based, veterinarian clarity and practical tips for 2025 and beyond.

1. What Is PPID? 🧬

PPID results from overactivity and enlargement of the pars intermedia region of the pituitary gland, leading to excess ACTH and downstream hormonal imbalances. In the absence of inhibitory dopamine control, this causes widespread metabolic and immune dysregulation :contentReference[oaicite:4]{index=4}.

2. Who’s at Risk & Prevalence 📊

Primarily affects older equids—most diagnosed around age 19, though younger horses (10–15 years) may also develop it; prevalence reaches ~21% in horses over age 15 :contentReference[oaicite:5]{index=5}. Ponies and Morgans appear predisposed.

3. Early vs Advanced Clinical Signs

It’s crucial to distinguish subtle, early indicators from more obvious signs:

Early (Dimension 2 signs) include:

• Poor performance, lethargy, muscle weakness, acute laminitis, weight loss :contentReference[oaicite:6]{index=6}

Advanced (Dimension 3 signs):

• Hypertrichosis (long, curly coat), delayed shedding, “laminitic episodes”, abnormal fat distribution—supraorbital or tailhead fat pads :contentReference[oaicite:7]{index=7}

4. Metabolic Overlap & Insulin Dysregulation

PPID frequently coexists with Equine Metabolic Syndrome (EMS). Both carry laminitis risk. Horses with both PPID and insulin dysregulation produce excess insulin post-eating :contentReference[oaicite:8]{index=8}.

5. Diagnostic Testing 🧪

1. Baseline plasma ACTH: Season-adjusted, autumn is ideal, but stress can skew results :contentReference[oaicite:9]{index=9}.
2. TRH stimulation: Greater sensitivity—best for early disease :contentReference[oaicite:10]{index=10}.
3. Oral sugar / fasting insulin tests: Assess insulin dysregulation :contentReference[oaicite:11]{index=11}.
4. Follow-up testing: Repeat ACTH and insulin bi-annually :contentReference[oaicite:12]{index=12}.

6. Treatment Approach

🔹 Pergolide (Prascend®)

A dopamine agonist, first-line therapy. Effective in 65–85% of cases. Reduces ACTH, normalises hair coat, hydration, energy, laminitis risk :contentReference[oaicite:13]{index=13}.

Start low and adjust every 30 days with ACTH rechecks. Retest every 6–12 months :contentReference[oaicite:14]{index=14}.

Side effects: doxy appetite for 40%, initial colic or mood change—managed with slow ramp-up :contentReference[oaicite:15]{index=15}.

🔹 Adjuncts

• Cyproheptadine: Enhances dopamine effects—used when pergolide alone is unsuccessful :contentReference[oaicite:16]{index=16}.
• Insulin-sensitizing diets: Low NSC, soaked hay, ration balancers, trace minerals, vit E, B‑vitamins :contentReference[oaicite:17]{index=17}.
• Regular exercise: Enhance insulin response for non-laminitic horses :contentReference[oaicite:18]{index=18}.
• SGLT2 inhibitors: Under research—EMG 2024 suggests potential future therapies :contentReference[oaicite:19]{index=19}.

7. Research & Advancements

• UMN Genetic Study (April 2025): Investigating genetic markers predicting pergolide response :contentReference[oaicite:20]{index=20}.
• Texas A&M (Jan 2025): PPID and fertility – poor reproductive outcomes in affected mares :contentReference[oaicite:21]{index=21}.
• RVC Quality-of-Life Study: Developing QoL scoring tools for PPID horses :contentReference[oaicite:22]{index=22}.
• Pergolide reduces postprandial insulin in PPID with ID, per Melbourne research :contentReference[oaicite:23]{index=23}.

8. Managing Laminitis Risk

Laminitis is a severe PPID complication. Pergolide + diet + exercise reduces risk. Limit sugar/starch, soak hay 8–12 hrs, provide turnout/exercise routines :contentReference[oaicite:24]{index=24}.

9. Supportive Care Essentials

• Dental floating annually; older horses often have dental wear :contentReference[oaicite:25]{index=25}.
• Hoof care every 6–8 weeks to prevent laminitis.
• Infections: treat skin, sinus, hoof abscesses aggressively due to immune suppression :contentReference[oaicite:26]{index=26}.
• Hydration and electrolytes—monitor polydipsia/polyuria.
• Grooming: clip long coats; clean facial folds
• Monitor for neurologic signs–rare; consult vet immediately :contentReference[oaicite:27]{index=27}.

10. Frequency of Vet Visits & Monitoring

• Initial follow-up in 30 days then every 6–12 months—twice yearly is ideal :contentReference[oaicite:28]{index=28}.
• Monitor body condition, coat, eating, hoof health monthly.
• Re-test ACTH during autumn peak for accuracy :contentReference[oaicite:29]{index=29}.

11. Ask A Vet Support & Brand Integration 📲

Ask A Vet ensures full support for PPID management:

• 📲 Telehealth monitoring of symptoms and lab results
• 📦 Pergolide dosing tools with reminders and side‑effect tracking
• 🥕 Diet consults for low‑NSC/insulin control regimens
• 🎓 Trainer access for rehabilitation, fitness, weight loss
• 🧠 Educational resources: UV & enrichment by Purrz; medication tracking

12. Summary Table

Final Thoughts 🧡

PPID is a lifelong condition, but with early diagnosis, effective medication, dietary adjustments, and consistent monitoring, horses can enjoy quality lives into their late 20s and beyond. 2025 brings new insights in genetics and laminitis prevention—but the fundamentals remain best veterinary care. Trust your vet, stay vigilant, and lean on support systems like Ask A Vet to guide your journey.

For expert PPID support tailored to your horse, download the Ask A Vet app or visit AskAVet.com to connect with veterinary professionals, nutrition plans, medication reminders, and more. 🌟🐴

Disclaimer: This educational guide does not replace personalized veterinary care. Always consult your vet for specific medical decisions.