An atypical case of equine eosinophilic keratoconjunctivitis

Summary This case report describes an unusual presentation of eosinophilic keratoconjunctivitis (EK) in a horse. A 6‐year‐old Warmblood gelding was presented for acute blepharospasm and pruritus of the left eye. Topical antibiotics and/or corticoid treatments had been applied without success. The ophthalmic examination revealed a large granulomatous mass at the central part of the dorsal corneal limbus. This mass had a haemorrhagic appearance, and multiple caseous deposits were visible on the surface. Cytology and culture exams were performed under topical anaesthesia. Cytology revealed significant eosinophilic and neutrophilic inflammatory infiltrates. Bacteriology and mycology cultures were negative. A keratoconjunctivectomy was performed under sedation and topical anaesthesia, and the sample was submitted for histology. A rapid improvement in clinical signs was observed. The histopathological analysis revealed abundant degenerative and necrotic tissue, strongly eosinophilic, also extending into the corneal stroma with adjacent areas of collagenous necrosis. The proliferative nature of the lesion was linked to the intensity of the inflammatory reaction. There were no visible pathogens. One year later, no signs of recurrence were observed. This case report describes a necrotic and proliferative form of EK in a horse with a successful surgical outcome.