What Is Equine Cushing’s Disease?

Signs, Diagnosis & Management for Horse Owners

Equine Cushing’s Disease, officially known as Pituitary Pars Intermedia Dysfunction (PPID), is one of the most common hormonal conditions affecting older horses and ponies. With early recognition and the right management, horses with PPID can continue to live long, active, and happy lives.

What Causes PPID?

PPID is caused by changes in the pituitary gland, a small structure at the base of the brain that helps regulate hormones. In horses with PPID, part of the pituitary becomes overactive and produces too much of certain hormones — particularly ACTH, which stimulates excess cortisol production (the “stress hormone”).

This hormonal imbalance disrupts the body’s normal function and can lead to a variety of clinical signs.

Common Signs of Equine Cushing’s Disease

PPID can be subtle at first, but some of the most typical signs include:

Long, curly coat that doesn’t shed properly in spring
Muscle wastage, especially along the topline
Weight loss despite a good appetite
Lethargy or lack of energy
Increased drinking and urination
Recurrent laminitis (even in the absence of grass intake)
Recurrent infections (e.g. skin infections or hoof abscesses)
Sweating excessively
Abnormal fat deposits, especially over the eyes or crest

Not all horses show every sign, and early cases may only have one or two mild symptoms.

How Is It Diagnosed?

The most common way to diagnose PPID is via a blood test that measures ACTH levels. This is best done in autumn, when natural ACTH levels are higher, making it easier to spot abnormal results.

Sometimes, further tests are needed, especially if results are borderline or symptoms are unclear.

Can It Be Treated?

Yes. While PPID can’t be cured, it can be effectively managed.

The most common and effective treatment is a daily medication called Pergolide (marketed as Prascend® or Pergoquin®), which helps normalise hormone levels.
Regular blood tests help monitor and adjust treatment over time.
Supportive management — such as careful diet control, routine dental and hoof care, clipping long coats, and managing pain — is just as important.

Is Diet Important?

Absolutely. Horses with PPID often have insulin dysregulation, making them more prone to laminitis. Feeding a low-sugar, low-starch diet is vital.

Avoid rich grass and sugary treats.
Use hay with known sugar content (soaked hay may help).
Feed a balanced vitamin and mineral supplement, especially if on restricted grazing.

Can Young Horses Get PPID?

PPID mostly affects older horses, usually aged 15+, but it can occur in horses as young as 7. Some signs, like laminitis or weight changes, may be mistaken for ageing, so it’s worth investigating if you're unsure.

Final Thoughts

Equine Cushing’s Disease is a long-term condition, but with good management and veterinary support, most horses can continue enjoying life well into their senior years.

If your horse is showing signs of PPID, a simple blood test can provide the answers. Early diagnosis and treatment often lead to better outcomes — and a much happier horse.