Last Update: 11/22/2017 10:30:00 AM
Ask The Horse Doctor: Left untreated,Cushing's disease can lead to other problems
Ask the Horse Doctor By Dr. Christina Vittoria
Dear Dr. Vittoria: I think my stallion has Cushing's disease, or as I think they call it now, PPID. This spring he did not shed so we clipped him. His hair is growing in curly. Is there special or better feed for him to eat? He is 23 but can still eat hay and grain. Will I need to have him on medication to help him shed out and be comfortable? - Concerned Mom
Dear Concerned Mom: You are probably guessing right that your stallion has Cushing's disease. The main sign of this disease is excessively curly and fast-growing hair. The fancy term for this symptom is hirsutism. But we almost never use this word because nobody would understand us.
PPID is the abbreviation that stands for Pituitary Pars Intermedia Dysfunction. This describes the specific location in the pituitary gland of the brain that is affected.
Essentially, the disease is from a tumor in the brain that is rarely locally invasive but does produce hormones. These hormones cause the body to release a large amount of steroid. Steroids have a systemic effect that can be detrimental to your horse's health. Many times, these horses have elevated insulin levels, which makes it harder for them to process sugar. When this happens, it puts them at risk for severe laminitis.
The laminitis can be very damaging to the hooves and contribute to severe lameness. If your stallion starts to walk like he is stepping on eggshells, you'll want to call your vet. Many horses will not heal from the laminitis until they have their Cushing's disease corrected.
The elevated steroids also contribute to a diminished immune system. Horses with Cushing's disease will often have a harder time healing. We see more hoof abscesses in these horses, as well as eye ulcers, that do not heal easily. These may be reasons to get your horse tested.
The simplest test is an ACTH level (adrenocorticotropic hormone). This blood test is quite effective at diagnosing and monitoring this disease. Because metabolic conditions can occur with Cushing's disease, vets will also run insulin resistance testing with the ACTH level. Once diagnosed, you can proceed to getting your horse treated.
Unfortunately, there's no cure for Cushing's disease. It is treated by constantly keeping the tumor's function in check. The treatment of choice is Prascend, a daily medication your horse will take for life. It tells the tumor to stop producing steroid.
Once on treatment you will see your horse's coat return to normal. Don't worry about winter, they can still generate a normal winter coat, but they won't look like a hairy mammoth.
Because they are prone to concurrent metabolic diseases, we recommend keeping them on a low starch feed. This will help eliminate any possibility of inflaming the situation if he is borderline laminitic. It sounds like your stallion is exhibiting symptoms of this disease and he should get tested soon.
Christina Vittoria, D.V.M., practices equine, small ruminant, and companion animal medicine at Willow Creek Veterinary Center. Comments offered here are for educational purposes only. Readers should consult their veterinarian before taking action. Have a question for Dr. Vittoria? Send it to firstname.lastname@example.org. Please put ASK THE VET in the subject line.