Systematic Literature Review of Risk Factors and Treatments for Ulcerative Dermatitis in C57BL/6 Mice

Ulcerative dermatitis (UD) in C57BL/6 mice is poorly understood and challenging to treat. We sought to evaluate the evidence regarding commonly cited risk factors for UD and reported UD treatments. The terms 'ulcerative dermatitis' and 'C57BL/6' were used to search 3 electronic databases. The resulting 347 articles were screened to identify publications that compared the risk of spontaneous UD in wild-type C57BL/6 mice according to sex, season, diet, or age and those that compared the degree of healing or rate of lesion resolution according to the intervention used. Articles were evaluated by using published criteria for assessing methodologic quality, including study design, number of animals per study group, case definition, method of diagnosis, randomization, enrollment criteria, exclusion criteria, and outcomes. The search identified 11 publications on risk factors that met the inclusion criteria, and no publication on UD treatment met all of the criteria. Relaxing the inclusion criteria for reporting of risk factors and treatment outcomes to include both wild-type C57BL/6 mice and genetically engineered mice on a B6 background yielded 12 publications on risk factors and 3 publications on treatment. Dietary factors, particularly caloric restriction, appear to influence UD risk. Female sex was inconsistently associated with a higher risk of UD, which most often occurred in 13- to 24-mo-old mice in the studies that were reviewed. Only 1 of the 3 publications that evaluated UD treatments included an untreated group or alternative therapy control. Further research is needed to explore epidemiologic aspects of UD and to compare treatment options.