The Facts

• Older horses are more likely to develop Cushing's disease than young ones. The syndrome is more common in ponies than in full-size horses, and it is often missed or misdiagnosed because of the vague and patchy symptoms. Cushing's is not fatal on its own, but side effects like laminitis (acid in the feet) and infection can be deadly.
  
  

Causes

• Equine Cushing's occurs when a horse has a pituitary tumor. The pituitary gland regulates a horse's endocrine system, including its adrenal gland, and therefore regulates the productivity and release of the adrenal hormone cortisol. A tumor in this gland disrupts its ability to regulate cortisol in the body.
  
  

Symptoms

• According to EquiSearch, Cushingoid horses are most easily identified by their coarse, wavy coats. Their long hair fails to shed during the summer and is most evident on a horse's face and ears. Other symptoms include thirst, excessive urination, a pot-bellied appearance and loss of muscle mass. Horses with Cushing's have compromised immune systems and are more vulnerable to infection.
  
  

Treatments

• Treatments for Cushing's include both drugs and lifestyle management. Cushing's drugs seek to control both the pituitary and adrenal glands to control cortisol release and relieve the symptoms of the disease. Owners are advised to keep horses clipped and exercised, to relieve physical symptoms, and to feed the horse low-acid foods.
  
  

Research in the UK

• Some of the most important Cushing's research is currently done in the UK. According to Web.UKOnline.co.uk, the Royal Veterinary College in the UK is spearheading tests on the Cushing's drug Trilostane. This drug blocks the adrenal gland to control cortisol release and treat Cushing's. In a test of Cushingoid horses, Trilostane improved symptoms over a space of 30 days. Proponents in the UK hope to push this new drug as an alternative to standard Cushing's medications.