Has your horse become depressed and long-haired? It might have PPID.

17. October, 2023

Is your horse’s coat getting more and more shaggy over the years? Is the coat becoming curly? Your horse might possibly have Pituitary Pars Intermedia Dysfunction – commonly abbreviated as PPID and also known as Equine Cushing’s Syndrome.

More than 20% of all horses over 15 years old develop PPID. In the early 1970s, the prevalence of PPID among about 4,000 horses treated by veterinarians was estimated to be between 0.075 percent and 0.15 percent. Some numbers today indicate that about 20% of all older horses, ponies, and donkeys develop the disease. PPID can affect horses and donkeys of all breeds and types, while ponies and Morgan horses are at higher risk. There seems to be an equal risk of PPID in mares, stallions, and geldings.

PPID develops over time and is usually diagnosed in older horses. PPID can be challenging to detect because the disease develops over many years. Therefore, it is usually older horses – between 18-23 years old – that are diagnosed with PPID. Although more and more horses have been diagnosed and treated for PPID in recent years, there is no evidence that there are actually more horses getting PPID. When more cases are detected, it is probably because veterinarians have become better at diagnosing PPID, and more horse owners are aware of the disease, noticing the long and curly coat, for example.


Symptoms of PPID

PPID is a syndrome disease, meaning it consists of a wide range of different symptoms that can vary from horse to horse. This makes it harder to detect the disease, as mentioned, it develops over time. Here is a list of the most common symptoms of PPID:

Long and curly hair:

A common symptom of PPID is long and curly hair that doesn’t shed – initially, the hair may only grow on the lower jaw and other parts of the limbs. Over time, the horse can develop more and more hair, and the color of the coat can change.

Bad mood:

PPID is a disease in the pituitary gland, which is part of the brain. Therefore, the disease affects various substances and hormones. One of them is dopamine. Just like in humans, a lack of dopamine affects the mood in horses, so a symptom of PPID can be that your horse appears depressed.

Sweating problems:

Two-thirds of horses with PPID experience sweating problems – especially over the neck and shoulders.

Weight loss:

Weight loss is common in horses with PPID. In addition to actual weight loss, the horse loses muscle mass, especially in the hindquarters. Weight loss can be a difficult sign for you as a horse owner to notice. This is because weak and stretched abdominal muscles often mean that the belly continues to look round, effectively hiding the weight loss. Even if your horse is losing weight, you may still perceive its appetite as normal or even increased. There is often fat deposition along the crest of the neck, over the tail base, in the sheath of male horses, and above and behind the eyes.

Increased thirst:

Increased thirst and more urination are symptoms in between 33 and 75 percent of horses with PPID.

Bad teeth:

PPID can cause dental problems that can lead to painful chewing, resulting in reduced feed intake, which in turn causes the horse to lose weight.


Fatigue and poor performance often affect horses with PPID, which may become excessively calm and even more pain-tolerant than healthy horses.

Wounds and infections:

Wounds in horses with PPID heal worse than in healthy horses, and the horse can be affected by various infections. This is often an overlooked symptom of PPID.

Chronic laminitis:

Chronic laminitis might be the most serious symptom of PPID. Some research suggests that chronic laminitis affects more than half of all horses with PPID. Chronic laminitis is a painful condition that sometimes leads to hoof abscesses and can become so severe that the horse has to be euthanized.

How the veterinarian diagnoses PPID

In practice, the veterinarian determines if your horse has PPID by examining its coat and checking for a range of other symptoms. The vet can also conduct various clinical tests. However, they are unfortunately not entirely reliable.

How PPID is treated

Treating horses with PPID requires, first and foremost, that you take good care of your horse’s grooming and health. Your veterinarian will also prescribe a prescription medication to help your horse. In the early stages of PPID, where increased hair growth and sweating might be the primary symptoms, it might only be necessary to clip your horse’s coat. Since many affected horses are older, regular grooming and dental correction are important. You should also consider what feed your horse should have. It might need a special diet – preferably not sweet feed with high soluble carbohydrate content – unless, of course, it is the only thing the horse will eat. Since it’s hard to see how much weight the horse is losing and how much muscle mass it’s losing, it might also be necessary to weigh or measure it regularly. One of the worst complications of PPID is, as mentioned, recurrent or chronic laminitis, so regular hoof care is essential to reduce the risk of it getting worse. You should also talk to your vet about medical treatment that can help your horse.

Prognosis for horses with PPID

Once your horse has PPID, it has the disease for life. However, PPID can be effectively managed with a combination of changes in care, grooming, and medication.


Schott, H. C. (2002). Pituitary pars intermedia dysfunction: equine Cushing’s disease. Veterinary Clinics: Equine Practice, 18(2), 237-270.