Topical creams containing corticosteroids like dexamethasone are prescribed for inflammatory or allergic skin conditions, sometimes for arthritic joints. However, even this local application can have systemic effects. A study performed at the veterinary school of Leipzig University found that daily application of 50 grams (just under 2 ounces) of a dexamethasone-containing skin cream caused suppression of the pituitary and adrenal gland within 2 days and caused changes in the white blood cells typical of oral or injected corticosteroids.
For healthy horses, these changes mean a reduced ability to respond to stress and increased risk of infections or developing allergies. Horses with Cushing’s disease or insulin resistance could be at increased risk of laminitis, or experience worsened laminitis. Corticosteroid creams should be used in the smallest amounts and for the shortest period possible. Possible alternatives include aloe-based ointment or cream for topical problems, and Sore-No-More liniment for musculoskeletal problems.