Macroscopic, cytological and bacteriological evaluation of anal sac content in normal dogs and in dogs with selected dermatological diseases

Abstract

Macroscopic and cytological aspects of anal sac content were evaluated in 40 normal dogs and 10 dogs each with pyoderma, Malassezia dermatitis associated with atopic dermatitis and uncomplicated atopic dermatitis. Bacteria isolated from anal sacs were compared with those from abdominal skin and hair in 20 normal dogs and 10 dogs with pyoderma. There was no difference between the groups in anal sac dimension, or in the colour, consistency or presence of granules in their content. Extracellular bacteria were found in higher numbers in diseased animals, whereas intracellular bacteria were observed in 40% of dogs with pyoderma and in only 2.5% of normal dogs. Malassezia spp. were present in 15.7% of dogs, with no difference between groups. Neutrophils were observed in 12.5% of normal dogs, 30% of dogs with Malassezia dermatitis with underlying atopic dermatitis and in 70 and 80% of dogs with pyoderma and uncomplicated atopic dermatitis, respectively. Seven bacterial species were isolated from anal sacs, with no difference between normal dogs and dogs with pyoderma. In five normal animals and in four dogs with pyoderma the same bacterial strains were isolated from anal sacs and from abdominal skin and hair.

Perianal pruritus in dogs with skin disease

“…As previously reported, we confirmed that anal sac content can be very variable in colour and consistency. Likewise, no significant correlation was found between anal sac impaction, colour or content consistency and the presence or absence or perianal pruritus in dogs without anal sac disease.…”

“…The anal region was wiped with a paper cloth, prior to squeezing the other sac. The anal sac was evaluated for impaction and for its content, colour (cream, beige, brown or dark brown) and consistency [liquid (watery), fluid with granulations, viscous (syrupy), viscous with granulations, pasty or dense] as previously described …”

Reproducibility of a semiquantitative method to assess cutaneous cytology

“…The results obtained in this study cannot be compared with the results of other studies, because a different scale and classification was used. In addition, criteria for reproducibility were not mentioned in other studies 9,10,15 . To the authors’ knowledge, intra‐observer reproducibility and interobserver reproducibility for evaluation of cytological samples of more than two investigators have not been studied.…”

Comparison of anal sac cytological findings and behaviour in clinically normal dogs and those affected with anal sac disease

“…Recently, three published studies evaluated anal sac cytology in normal dogs and in dogs with specific skin disease, but did not evaluate dogs with ASD 7–9 . These studies indicate that the anal sacs of clinically normal dogs have a wide variation of cytological findings, including the presence of inflammation and intracellular bacteria 7–9 . Nelson and Couto’s Small Animal Internal Medicine text offers guidance in diagnosis of anal sacculitis based on physical and rectal examination 10 .…”