Nonhealing corneal ulcers as a manifestation of bullous pemphigoid in a horse

Summary An 18‐year‐old Quarter Horse cross gelding was referred for a 2‐month history of keratitis, conjunctivitis, sloughing of oral mucosa and multifocal areas of crusting and alopecia along the neck, shoulders, withers, back, anus and perineal region. On presentation, there was severe blepharospasm, keratitis and bilateral superficial corneal ulceration. Corneal cytology and biopsy of the right cornea were consistent with necrotising keratitis with no evidence of infectious or neoplastic aetiologies. Histopathological examination of multiple sections of haired skin indicated a subepidermal vesicular dermatitis consistent with a bullous pemphigoid type condition. The gelding was treated with azathioprine and dexamethasone systemically, resulting in improvement in dermatologic and mucocutaneous lesions. Topical administration of cyclosporine and dexamethasone resulted in resolution of corneal ulcerations in 24 days. This report describes the presentation, treatment and possible underlying pathophysiology of a suspected ocular manifestation of a vesiculobullous disease.