Feline acne and results of treatment with mupirocin in an open clinical trial: 25 cases (1994–96)

Clinical and diagnostic parameters, and response to topical mupirocin in 25 cats with feline acne are described. The chin was the most common area affected, but the lower lip, upper lip and the commissure of the lips also frequently had lesions. The most common clinical sign was the presence of crusts, followed by comedones, erythema, alopecia, pruritus and nodules/fistulas. Deep skin scrapings for ectoparasites, cytological examination of superficial skin scrapings, and fungal cultures from the chin were performed on all cats. Dermatophytes were cultured from two cats and Malassezia pachydermatis was cultured ( n  = 2), seen on cytology smears ( n  = 1), or noted on histopathology ( n  = 1). Skin biopsies were obtained from three of the cats and most commonly showed dilatation of sebaceous gland ducts, neutrophilic or pyogranulomatous infiltration of the sebaceous glands, and pyogranulomatous inflammation of the dermis.
All cats were treated with topical 2% mupirocin ointment twice daily for 3 weeks as the sole treatment. Treatment response was excellent in 15 cats and good in nine cats. One cat had a contact reaction to the mupirocin, necessitating stopping treatment. The response to treatment of the six cats with dermatophyte or years involvement was good ( n  = 3) or excellent ( n  = 3).