Eosinophilic keratitis in cats

Feline eosinophilic keratitis is a chronic, proliferative inflammation of the cornea. Pathogenesis: The exact pathogenesis is still unknown, it may involve infection with FHV-1 (Feline herpesvirus-1). Clinical presentation: The disease is usually unilateral and appears more often in young and middle-aged castrated males. First symptom is perilimbal corneal vascularisation. As the disease progresses irregular, white-pink plaques appear on the dorsotemporal or ventronasal quadrant of the cornea. The lesions are usually covered with corneal epithelium, ulceration is seen only 25% of the cases. Diagnosis: Clinical presentation is typical for the disease. Corneal scraping can ver-ify the diagnosis. Detection of one eosinophil or mast cell in cytology is diagnostic. Treatment: Treatment usually consists of topical corticosteroids (0.1% dexametha-son- or prednisolon-acetate) and cyclosporine. Some cats develop adverse reac-tion to topical treatment. In these cases, systemic medication is necessary. Oral megestrol acetate is an effective treatment for eosinophilic keratitis but there are potential side effects, such as diabetes mellitus, pyometra and mammary gland tumour. Therefore, megestrol acetate is only used if topical treatment cannot be maintained. As the role of herpesvirus in the disease is still unclear, additional treat-ment with famciclovir is recommended. Initial response to the therapy usually good but over time recurrence rate is more than 50%