Cytologic examination of pustule contents may provide a tentative diagnosis based on the presence of individual to rafts of immature and free-floating (acantholytic) keratinocytes, in addition to intact neutrophils and occasional eosinophils (
See Figure 5, Cytologic preparation showing neutrophils and large rounded (acantholytic) keratinocytes). However, histopathologic examination of skin biopsy tissues (ie, intact pustule when possible) is required for definitive diagnosis.
TREATMENT
The treatment protocol requires immunosuppressive therapy. Although treatment for canine pemphigus foliaceus often requires multidrug protocols, administration of corticosteroids alone may be successful in cats. The author prefers treatment with dexamethasone in cats (0.22 mg/kg q24h at a tapering dose) as the initial corticosteroid choice. When combination therapy is instituted, chlorambucil (2 mg/m2 q48h) or cyclosporine (5 mg/kg q24h) may be added.
In general, secondary bacterial infections are a less significant concern in cats than they are in dogs. However, when bacteria are present in cytologic preparations, infections must be controlled with oral antibiotics and topical antiseptic bathing in the induction treatment phase. Cases complicated by previous antibiotic administration may require exudate culture and sensitivity testing for selection of appropriate medication.
PROGNOSIS
Prognosis for feline pemphigus foliaceus is fair to good. As with dogs, affected cats benefit most from aggressive initial treatment that induces remission, followed by maintenance therapy for long-term control of the disease.
ALEXANDER WERNER, VMD, DACVD, is owner of Animal Dermatology Center in Studio City, California. In addition to clinical practice and presenting lectures throughout North America, he has published numerous articles and book chapters on dermatology. Dr. Werner is coeditor of the latest edition of Blackwell’s Five-Minute Veterinary Consult: Small Animal Dermatology as well as editor for the next edition and coeditor of the most recent clinical companion. Dr. Werner received his VMD from University of Pennsylvania and completed his dermatology residency at University of California, Davis.