Anal sacculitis refers to inflammation and\/or infection of 1 or both anal sacs. It is a common non-neoplastic anal sac disease in dogs with a heterogenous presentation. Although few studies exist regarding this disease, there has been an increased interest in the past few years. This brief review discusses what is known about the factors related to the development of anal sacculitis and treatment of the condition, with a focus on the recent literature. Anal sacculitis is typically considered secondary to an underlying condition, but so far little evidence exists for a connection between anal sacculitis and conditions other than allergic skin disease or atopic dermatitis. Further research is needed to help elucidate risk factors for this disease. Localized treatment of anal sacculitis with flushing and infusion appears to be an effective alternative to the use of systemic antibiotics. While most dogs respond well to this treatment, disease may recur if treatment is not adequate and potential underlying factors are not identified and addressed.<\/p>\n
Take-Home Points<\/b><\/p>\n Most carnivores have paired, spherical pouch-like sacs bilateral to the anus with a single duct opening to lateral margins of the anal sphincter, termed anal sacs. These sacs serve as receptacles for the secretions of the apocrine and sebaceous glands, which line their walls and are thought to play a role in scent communication.1<\/sup> Anal sac contents are secreted passively during defecation but can also be actively expressed when a dog experiences fear. Problems arise when the anal sac contents are not evacuated normally and begin to build up, resulting in discomfort.2<\/sup> Non-neoplastic anal sac disease (NASD) can include anal sac impaction (anal sac overfilling), anal sacculitis (inflammation with or without infection), and anal sac abscessation (rupture of the anal sac, leading to cellulitis and deep infection of surrounding tissue).2,3<\/sup> These conditions are typically considered to exist on a continuum and are common in dogs, with a reported incidence ranging from 4.4% to 15.7% in primary care practices.2-4<\/sup><\/span><\/p>\n Anal sacculitis accounts for approximately 12% of all NASDs.4<\/sup> Several factors, including allergic skin disease, breed, stool quality, diet type and changes, obesity, and other perianal skin diseases, are suggested to play a role in the development of anal sacculitis.3-7<\/sup> However, few studies investigating the etiology of anal sacculitis exist.<\/span><\/p>\n In 2 retrospective studies, allergic skin disease\u2014s<\/span>pecifically atopic dermatitis caused by food and\/or environmental triggers\u2014was identified as the most common comorbidity for dogs with anal sacculitis.5,7<\/sup> This is consistent with the view that allergic skin disease can lead to perianal inflammation, contributing to anal sac duct stenosis, impaction, and ultimately anal sacculitis.4<\/sup> However, due to the retrospective nature of these studies, while a relationship is <\/span>suggested, true causation is not confirmed. Interestingly, a recent study using bacterial 16S rRNA gene sequencing found that there was a significant difference in the bacterial microbiota between the anal sacs of healthy and untreated atopic dogs as well as between treated and untreated atopic dogs.8<\/sup> This indicates that atopic dogs experience anal sac dysbiosis, which may predispose them to the development of anal sacculitis.8<\/sup><\/span><\/p>\n Breed may also play a role in the development of anal sacculitis. In a study investigating the development of NASD, a strong predisposition was found for spaniel and brachycephalic breeds.4<\/sup> This predisposition may not directly translate to anal sacculitis predisposition specifically. Two retrospective studies focusing on anal sacculitis found German shepherds and Labrador retrievers to be the 2 most highly represented breeds; these breeds were the most represented by narrow margins, and true risk has not been established.5,7 <\/sup>At this time, it is uncertain how much a role breed plays in the development of anal sacculitis; in the authors\u2019 experience, it can occur in a wide variety of breeds.<\/span><\/p>\n One study identified a history of diarrhea prior to the development of clinical signs of anal sacculitis in 75% of cases.6<\/sup> Of these dogs, 75% were fed either all-meat diets or diets containing chop bones and had a history of either poor stool quality or rectal impaction.6<\/sup> In contrast, a more recent retrospective study found that only 20.6% of dogs with anal sacculitis had poor stool quality.5<\/sup> This difference may be explained by the fact that most dogs in the second study were fed commercially available dog food. However, the latter study was performed at a <\/span>dermatology referral practice, where there was a delay between onset of signs related to anal sacculitis and presentation to the clinic, meaning some cases of poor <\/span>stool quality prior to development of anal sacculitis may not have been captured.5<\/sup> While stool quality may be <\/span>involved in the development of anal sacculitis for some individuals, it is not a consistent finding.<\/span><\/p>\n Obesity has also been reported to be implicated in the development of anal sacculitis.2<\/sup> However, a large retrospective study of dogs in the United Kingdom found no association between obesity and NASD.4<\/sup> When dogs are evaluated for obesity, a body condition score (BCS) ranging from 1 to 9, with an ideal of 4 to 5, is commonly used.9<\/sup> Looking specifically at anal sacculitis, a retrospective study of dogs in Sweden found that 63.6% had an ideal BCS of 5 and 36.3% were slightly overweight with a BCS of 6.7<\/sup> All dogs were scored at either a 5 or 6.7<\/sup> In a retrospective study on dogs with anal sacculitis in the United States, 45.2% had an ideal BCS of 4 or 5.5<\/sup> The remaining 54.8% of dogs were overweight with a BCS of greater than 6, and 9.7% were obese with a BCS of 8 or 9.5<\/sup> Based on these results, it is still uncertain how much of a role obesity plays in the development of anal sacculitis, although it may be less than previously thought.<\/span><\/p>\n Clinical signs associated with anal sacculitis include scooting, licking\/chewing the perianal region, blood in the stool, and\/or leaking anal sacs.5<\/sup> Affected animals may present with 1 or a combination of these clinical signs. On rectal examination, the anal sac wall may be diffusely thickened and there may be hemorrhagic to purulent discharge present upon anal sac expression.5,6<\/sup> Cytologic findings from the material of clinically normal and affected canine anal sacs are reported to be highly variable.10-13<\/sup> Although controversial, the presence of moderate to large numbers of erythrocytes with or without moderate to large numbers of inflammatory cells and coccoid and\/or\u00a0 <\/span>rods or yeast on cytology may be used to support the diagnosis of anal sacculitis when combined with the history and clinical assessment.10-12<\/sup><\/span><\/p>\n Many protocols for treatment of anal sacculitis have been proposed. Although systemic antibiotics have commonly been prescribed for cases of anal sacculitis, there is evidence that localized treatment is becoming more popular, with 1 study finding that 73.1% of dogs with anal sacculitis in a primary care practice in Sweden were treated with localized treatment, with or without systemic NSAIDs, and an additional 13.5% received local treatment with a systemic immunomodulatory medication, with or without systemic NSAIDs.7<\/sup> In the study performed at a U.S. dermatology referral center, 54.5% of dogs had been prescribed at least 1 course of <\/span>antibiotics prior to presentation, without full resolution of the problem.5<\/sup> With the increasing incidence of antibiotic resistance, a focus on localized treatment improves antimicrobial stewardship because it reduces the use of systemic antibiotics. <\/span><\/p>\n A published protocol for localized treatment of canine anal sacculitis involves5<\/sup>:<\/span><\/p>\n\n
Allergic Skin Disease<\/h2>\n
Breed<\/h2>\n
Stool Quality And Diet<\/h2>\n
Obesity<\/h2>\n
Diagnosis<\/h2>\n
Treatment<\/h2>\n
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