A retrospective study showed that, while remission rates were high, immunosuppressive therapy rarely cured the dermatologic disorder.
The autoimmune disorder feline pemphigus foliaceus (PF) typically causes dermatologic lesions on the face, ears, and paws. Immunosuppressive therapy, including glucocorticoids, cyclosporine, and chlorambucil, is commonly used to treat the disorder, and typically remission is observed with treatment.
Because the majority of existing literature focuses on PF treatment by veterinary specialists, researchers retrospectively studied disease outcome for cats treated in primary care practices. Their findings were recently published in Journal of Small Animal Practice.
Diagnosis and Clinical Signs
Forty-three cases of histologically confirmed feline PF were identified via email surveys from Veterinary Information Network members. Cases occurred in the United States, Canada, United Kingdom, Italy, Australia, and New Zealand. Most cases were domestic shorthair cats, all were spayed or neutered, and the median age of PF onset was 6 years.
Most cats were diagnosed within 2 months of first exhibiting clinical signs consistent with PF. The most common dermatologic lesion sites were the ears, haired areas of the face, and nail beds. Bilaterally symmetric crusts were most common, although paronychia, erosions, and alopecia were each reported in over half of the cats. Approximately half of the cats were also lethargic and/or pruritic. All dermatophyte cultures and tests were negative.
Treatment and Outcome
Eighty-eight percent of the 43 cats received systemic antibiotic treatment before being administered immunosuppressive therapies. Thirty-one cats received glucocorticoid therapy alone, while 11 received a combination of glucocorticoids and cyclosporine. Prednisolone was the most commonly prescribed glucocorticoid with a median dose of 2.2 mg/kg/day, and most cats received the oral rather than injectable form. The median dose of cyclosporine was 7 mg/kg/day.
Follow-up information was available for 40 cats. Of these, PF went into remission for 90% that were treated with glucocorticoids alone and for 73% receiving combination therapy. Use of a higher prednisolone dose offered no additional therapeutic benefit compared with lower doses. Also, use of cyclosporine did not significantly affect disease remission outcome. PF relapsed in 73% of cats after initial remission, necessitating continued or altered treatment. Maintenance therapy was continued for 28 cats, 18 of which received altered treatment regimens consisting of the addition or removal of glucocorticoids and/or cyclosporine.
Disease outcome information, available for 38 cats, was as follows:
Eleven cats experienced 1 or more glucocorticoid-related adverse effects, including polyuria and polydipsia, corneal ulceration, diabetes mellitus, hepatotoxicity, and intestinal hemorrhage. Adverse effects were more frequent with administration of injectable than oral glucocorticoids.
While remission rate was high for cats treated for PF in primary practice, relapse was also common. Also, approximately 25% of cats developed adverse effects from long-term immunosuppressive therapy.
Dr. Stilwell received her DVM from Auburn University, followed by a MS in fisheries and aquatic sciences and a PhD in veterinary medical sciences from the University of Florida. She provides freelance medical writing and aquatic veterinary consulting services through her business, Seastar Communications and Consulting.