13/09/2026
A shaggy coat, muscle loss, laminitis and a raised ACTH level: does that automatically mean Cushing’s?
Equine Cushing’s disease is now known as PPID: Pituitary Pars Intermedia Dysfunction. It affects the intermediate lobe of the pituitary gland.
Normally, glucocorticoids such as cortisol help keep hormone production under control. In horses with PPID, this control is disrupted. The pituitary gland becomes overactive, producing excess ACTH without the normal feedback mechanisms keeping them properly in check. It may also enlarge or develop benign adenomas.
ACTH acts on the adrenal glands, which produce glucocorticoids such as cortisol that normally gives a feedback signal to the pituitary gland to reduce ACTH production.
But here is the crucial point:
A hormone-producing pituitary adenoma can cause persistently raised ACTH levels. However, a raised ACTH result does not prove an adenoma is present – or confirm PPID on its own.
Season, breed, excitement, travelling and severe pain can all influence ACTH levels.
Chronic stress, insulin dysregulation, EMS, pain and other metabolic problems can also cause signs that resemble PPID. When these signs are not caused by PPID, Sanoanimal describes them as ‘pseudo-Cushing’s’ or ‘peripheral Cushing’s’.
If PPID is not the cause, symptoms may improve once the underlying problem is identified and addressed. That is why insulin regulation, diet, management, pain and hormonal factors all deserve a closer look.
Prascend can help horses with confirmed PPID to suppress the symptoms. Chasteberry, also known as agnus castus, is not a proven alternative: in one study, raised ACTH levels fell in just one of 12 horses.
Important note: Never change or stop prescribed medication without speaking to your vet.
Want to understand the bigger picture? Our online course: ‘Equine Cushing’s Syndrome’ explores the underlying causes, diagnostic challenges and practical next steps.
🔗https://shop.sanoanimal.com/product/lecture-equine-cushing-syndrome/
💬 Did you know that raised ACTH does not prove a pituitary adenoma?