Pituitary pars intermedia dysfunction (PPID), also known as equine Cushing’s disease, is a common endocrine disorder in aging horses, with prevalence increasing significantly after age 15. It results from degeneration of neurons controlling the pituitary gland, causing excessive hormone production, particularly ACTH and cortisol, which disrupts metabolic balance. Classic signs include delayed shedding, long wavy haircoat, lethargy, muscle loss, fat deposits, and laminitis. Diagnosis relies on hormone testing, primarily baseline ACTH (best from June to December) and TRH stimulation tests (January to June). Early diagnosis is crucial to prevent severe complications such as exercise intolerance, infections, and laminitis, which is linked to insulin dysregulation seen in about 30% of PPID cases.

While there is no cure for PPID, lifelong management with medications like pergolide (Prascend) can help control symptoms. Practical care includes body clipping, dietary adjustments to reduce sugar and starch intake, parasite control, and regular farrier care to prevent laminitis. PPID can coexist with equine metabolic syndrome (EMS), increasing laminitis risk. Owners should work closely with veterinarians to monitor hormone levels, adjust treatments, and manage overall health to maintain quality of life for affected horses.