Systemic granulomatous disease (SGD), also known as equine sarcoidosis (ES), is a systemic inflammatory disease of horses. It is characterized by exfoliative dermatitis, severe wasting, and granulomatous inflammation of multiple organ systems. It is considered to be uncommon in horse populations and is thought to be similar to sarcoidosis in humans, however SGD is much more severe in horses than for humans.

The onset of SGD in horses can be insidious or explosive, and usually is slowly progressive. Clinical signs observed in horses with SGD varies depending on the internal organ affected, which can include the lungs, lymph nodes, gastrointestinal tract, kidneys, bones, central nervous system, spleen, and liver.

SGD can occur as generalized, partially generalized or localized with the later being the most common occurrence in horses. SGD presents itself in three forms: (1)scaling and crusting form, (2) nodular form, and (3) the localized form in which hyperkeratotic, crusted, alopecic plaques are found on the limbs of the horse.

The preferred treatment is for horses with SGD is the administration of corticosteroids, preferably oral prednisolone over dexamethasone.