Cyclosporine as an alternative treatment for feline eosinophilic keratitis

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This chronic disease involving plaque formation on the cornea is a hypersensitivity reaction to an unknown stimulus. The most common treatment is corticosteroids. However, eosinophilic keratitis is possibly linked with feline herpesvirus infection, and corticosteroid therapy can exacerbate the infection. A study in Veterinary Ophthalmology investigated whether cyclosporine, which has immunosuppressive effects, is a good alternative therapy. From 1997 to 2007, the researchers identified 35 cats at Long Island Veterinary Specialists in which eosinophilic keratitis was diagnosed based on cytologic examination of the corneal lesions. Seven cats had bilateral disease. All of the cats had stromal corneal infiltration and superficial vascularization, and 12 cats had corneal ulcers. Twenty-six of the cats received 1.5% topical cyclosporine twice a day, and the other nine, which had more severe disease, received the cyclosporine three times a day. Cats that displayed or developed one or more clinical signs of herpesviral infection were concurrently treated with antivirals or topical antibiotics, or both.

After three weeks of therapy, signs of improvement were seen in 31 of the 35 cats (88.6%). During a follow-up period of at least five months, lesions recurred in seven of these 31 cats. These recurrences resulted from the owners discontinuing treatment. No systemic side effects were seen in any of the cats, but two cats developed blepharitis, and one cat was uncomfortable with the treatment, so the researchers switched the topical base from corn oil to mineral oil. The researchers concluded that 1.5% cyclosporine is effective in controlling eosinophilic keratitis in most cats with the condition. But because the disease is chronic and can only be controlled and not cured, long-term or possibly lifelong therapy is necessary.

Spiess AK, Sapienza JS, Mayordomo A. Treatment of proliferative feline eosinophilic keratitis with topical 1.5% cyclosporine: 35 cases. Vet Ophthalmol 2009;12(2):132-137.

Link to abstract: http://www3.interscience.wiley.com/journal/122232209/abstract