Symptoms of PPID

PPID signs can be extremely varied

Laminitis rings on hoof
Laminitis rings on hoof

Clinical Signs

Horses which are suffering from PPID can show a wide range of clinical signs, all of which are caused by the abnormally high circulating levels of the hormone cortisol.

In addition to laminitis another clinical sign associated with PPID is the development of an abnormal hair coat, ranging from mild changes in coat shedding right through to a full, long, curly, overgrown coat (“hirsuitism”). However, lots of horses with PPID do not develop this symptom.

Another common finding in horses and ponies with PPID is abnormal fat distribution – including abnormal fat bulging above the eyes (“supraorbital fat”) and a pot belly.

Other “classic” indicators of PPID include:

  • Excessive sweating

  • Increased appetite

  • Increased drinking and urination

  • Lethargy / poor performance

  • Repeating episodes of laminitis

  • Recurring infections (eg: sinusitis)

  • Loss of muscle condition, and/or a pot bellied appearance


In some cases, vets may make a diagnosis of PPID based simply on a clinical examination and an appreciation of the medical history of the horse or pony.

In many cases however, your vet will want to take one or more blood samples from your horse in order to measure blood levels of various hormones or markers. The results of these tests can then be compared to “normal” ranges for the horse population, to confirm the presence of absence of the disease.

Although a range of blood tests are available to assist the diagnosis and monitoring of PPID, the most commonly used test is the Resting ACTH test – where a single blood sample is taken to measure the level of the hormone ACTH which is abnormally high in untreated PPID cases. Talk to your vet about how your horse or pony could benefit from this test.