Cheyletiella infestation in the dog: observations on diagnostic methods and clinical signs.

The aims of this study were to evaluate the ability of diagnostic methods to detect naturally occurring Cheyletiella infestation in dogs, and to quantify and relate the number of mites and eggs present to clinical signs. Privately owned dogs with skin problems were eligible for inclusion in the study. Four diagnostic tests were performed on each dog in the following order: tape impression, hair plucking, skin scraping and vacuum cleaning. Dogs with positive test results for Cheyletiella infestation in at least one of the tests under evaluation were included in the study (n=27). The severity of pruritus and scaling was graded on a four-point fixed scale. The diagnostic findings in vacuum cleaning samples provided a semiquantitative measure of the grade of infestation. The vacuum cleaning test gave a positive test result in all dogs and was significantly more efficient than the other tests evaluated (P<0.01). The number of diagnostic findings varied considerably among the different vacuum samples. No significant relationship between the number of diagnostic findings and severity of clinical signs was detected.

Evaluation of a commercially available enzyme-linked immunosorbent assay for the detection of allergen-specific IgE antibodies in dogs.

Twenty-eight atopic dogs, 22 pruritic, non-atopic dogs and 10 healthy dogs were ELISA tested. For calculations of diagnostic specificity and sensitivity, positive ELISA test results in non-atopic dogs were considered false positive results. The absence of any positive results in the atopic dogs was considered false negative results. The atopic dogs were tested both with ELISA and an intradermal test, utilising allergen extracts from the same manufacturer, to determine the frequency of positive allergen reactions in the ELISA test compared with the intradermal test. The Prausnitz-Küstner test was performed to evaluate the significance of a positive ELISA test result. Based on cross-tabulations with clinically defined atopic dermatitis, the ELISA test showed a sensitivity of 53.6% and a specificity of 84.4%. The correlation between the ELISA and the intradermal test was poor. Positive Prausnitz-Küstner tests were not obtained using sera from dogs that were intradermal test negative for the tested allergens, even though sera had high levels of IgE as measured by the ELISA. These findings question the significance of a positive ELISA test result and indicate that the test is not measuring functional allergen-specific IgE.

Oral eosinophilic granuloma in three cavalier King Charles spaniels.

Oral eosinophilic granuloma is a rare and enigmatic disease in dogs. The clinical, haematological, cytological and histopathological features of three unrelated Cavalier King Charles spaniels with oral ulcers are presented. The disease was characterised by granuloma or plaque formation in the oral cavity. Common clinical signs were clearing the throat, swallowing problems, coughing during and after meals, reduced appetite and difficulty in eating. Haematological findings were not specific. Cytology was considered easier to perform than tissue biopsy due to friability of the tissue, but could not be used to confirm a granuloma diagnosis. The diagnosis of oral eosinophilic granuloma was verified histopathologically in each case. Response to glucocorticoid therapy varied, from complete remission to lack of any visible effect, leading to a guarded prognosis. The aetiology of the disease was not determined; however, the gross and microscopic morphologies of the lesions, their location and the response to corticosteroid therapy was suggestive of hypersensitivity.