Retrospective case-study analysis was performed at the “Serviço de Dermatologia" of the "Hospital Veterinário" of the "Universidade de São Paulo" using clinical records of cats presented to this institution. The sole purpose of the research was to determine the occurrence of feline skin diseases diagnosed at a specialized department of the veterinary teaching hospital for educational aims, among which are: therapeutic essays and upcoming research.

During a nine-year period extending from 1999 to 2007, a total of 1236 cats with skin diseases were presented to the institution. Among the specimen understudied, only 33% showed breed patterns, Persians (18.5%) and Siamese (12%) were overrepresented. There was no significant difference regarding sexual distribution, however, cats between the ages of 73 and 120 months were presented more frequently (20.9%) to the hospital. The distribution among other age groups was "less than 6 months," as follows: 9.8%, "6 to 12 months": 15.7%, "13 to 36 months": 18.2%, "37 to 72 months": 19.2%, and 16% "over 120 months". Only 20 of the cats could not have their ages determined by their owners.

As far as skin diseases are concerned, allergic dermatitis was the most commonly observed problem, as it was diagnosed in 288 patients (24%) (flea bite hypersensitivity--151/52.4%, non-defined allergic dermatitis--100/34.7%, food hypersensitivity--19/6.5%, and atopy--18/6.2%). Fungal ear and skin diseases were seen in 264 cases (21%) (dermatophytosis--197/74.6%, otomycosis--45/2%, cryptococcosis--10/3.8%, sporotrichosis--9/3.4%, mycetomas--2/0.7%, Malassezia dermatitis--1/0.4%). Parasitic ear and skin diseases were diagnosed in 209 (17%) cases (notoedric mange--79/37.8%, otoacariasis--45/25.3%, pediculosis--5/2.4%, flea infestation as main complaint--5/2.4%, and demodicosis--2/0.9%). Cutaneous neoplasms were seen in 147 cases (12%). Seborrheic and keratinization disorders were seen in 87 patients (7%) (ceruminous otitis--46/52.9%, acne--15/17.2%, seborrhea--14/16%, tail gland hyperplasia--12/13.8%). Bacterial ear and skin diseases were seen in 61 cases (5%) (bacterial otitis--44/72.1%, pyoderma--11/18%, abscesses--4/6.5%, pyotraumatic dermatitis--11/1.6%, mycobacteriosis 1/1.6%). Psychogenic dermatitis represented in 37 cases (3%). Eosinophilic granuloma complex (EGC) was observed in 34 cases (2.7%) (association of EGC presentations--17/50%, eosinophilic plaque--10/29.4%, indolent ulcer--5/14.7%, eosinophilic granuloma--2/5.9%).

Other less frequently diagnosed skin diseases included: pigmentary abnormalities (3/0.2%), claw diseases (2/0.2%), immunomediated skin diseases others than allergic ones (8/0.6%), environmental skin diseases (24/1.9%) and finally other dermatoses classified as miscellaneous skin diseases (72/5%).