Dermatology Challenge: Self-mutilation and over-grooming in a Siamese cat


Dermatology Challenge: Self-mutilation and over-grooming in a Siamese cat

Feb 01, 2005

A 2-year-old intact male Siamese cat was presented to the University of Wisconsin School of Veterinary Medicine's Dermatology Service for evaluation of self-mutilation and psychogenic licking of the forelimbs and abdomen. The owner reported that the problem had started shortly after she had gotten married and moved into her husband's apartment a year ago. The owner also said that the cat was emotional and bonded to her, which the cat expressed by grooming excessively in the husband's apartment and inappropriately urinating on the husband's dirty laundry. Before the move, the cat had lived in an old apartment building in the city. The only differences between the two apartments were that the old apartment had radiator heat and the new one had forced air heat and that the cat was now living with two other cats and a dog. The owner did not report any overt aggressive behavior among the animals or hiding on the patient's part. The owner had sought help from previous veterinarians for the behavior problems. Previous therapies included paroxetine hydrochloride (1 mg/kg once a day) for three months and feline pheromones (Feliway—Ceva Santé Animale) for one month, to which no responses had been noted; the cat had continued to over-groom. The cat had not received glucocorticoids before presentation, and it was not reported to have vomited hair or to have been constipated. All of the animals in the household were receiving a monthly spot-on for flea control, and none of them were reported to have any skin disease.

Clinical signs and differential diagnoses

1. The skin of the cats distal forelimb. Note the area of hair loss, erythema, and erosion indicating self-utilation. 2. The cats ventral abdomen. Note the hair loss.
The physical and dermatologic examinations revealed bilaterally symmetrical areas of matted hair and exudative eroded skin on the distal extremities and noninflammatory hair loss on the ventral abdomen (Figures 1 & 2).

It was difficult to determine whether the cat was over-grooming because of behavior problems or experiencing pruritus resulting in over-grooming. The fact that the clinical signs appeared after the cat moved into a new home and joined an established group of animals suggested that the problem was purely behavioral. However, pruritic cats often present with over-grooming as an owner complaint. The three major causes of pruritus in cats are parasites, allergies, and infections. Psychogenic skin diseases are rare and difficult to diagnose. So it was necessary to consider pruritus as the primary problem to work up.

Flea, lice, and Cheyletiella species infestations were unlikely because none of the other animals had clinical signs and all of them were receiving flea preventives monthly. And because the cat had been receiving prophylactic flea control before the onset of clinical signs and continued receiving it throughout the diagnostic period, flea allergy dermatitis was considered unlikely. Also, flea allergy dermatitis may have accounted for the hair loss on the abdomen but would not have explained the lesions on the forelimbs. Demodex gatoi infestation was a possible differential diagnosis even though the other cats appeared normal. Dermatophytosis and bacterial and yeast infections were additional differential diagnoses. Atopic dermatitis and food allergy were also considered as possible underlying triggers. The differential diagnoses for the inappropriate urination included cystitis, bladder stones, feline lower urinary tract disease, and behavioral causes.