Hirsutism in the older horse

Hirsutism is commonly encountered in older horses and ponies with Equine Cushing's Disease (ECD). The condition results from hypertrophy, hyperplasia, or adenoma of the pars intermedia of the pituitary gland which secrete abnormally high levels of proopiomelanocortin (POMC) and POMC-derived peptides such as adrenocorticotropin (ACTH) and α-melanocytestimulating-hormone (α-MSH). Although, ECD clinical signs are often typical, reaching a definitive diagnosis is frequently difficult in particular during the early stage of the disease. Currently, the most sensitive and specific tests for ECD diagnosis are Overnight Dexamethasone Suppression Test (ODST) and basal plasma ACTH concentration. However, both tests show a marked seasonal variation which may lead to a false diagnosis of ECD if testing is conducted during the Fall. Medical therapy with cyproheptadine or pergolide is fairly effective at controlling clinical manifestation of ECD including laminitis. A combination of careful health management, preventative medicine and medical therapy of ECD can significantly improve comfort and life expectancy of affected horses and ponies ...