Evidence‐based veterinary dermatology: a systematic review of the pharmacotherapy of canine atopic dermatitis

Abstract

The efficacy of pharmacological interventions used to treat canine atopic dermatitis, excluding fatty acid supplementation and allergen-specific immunotherapy, was evaluated based on the systematic review of prospective clinical trials published between 1980 and 2002. Studies were compared with regard to design characteristics (randomization generation and concealment, masking, intention-to-treat analyses and quality of enrolment of study subjects), benefit (improvement in skin lesions or pruritus scores) and harm (type, severity and frequency of adverse drug events) of the various interventions. Meta-analysis of pooled results was not possible because of heterogeneity of the drugs evaluated. Forty trials enrolling 1607 dogs were identified. There is good evidence for recommending the use of oral glucocorticoids and cyclosporin for the treatment of canine atopic dermatitis, and fair evidence for using topical triamcinolone spray, topical tacrolimus lotion, oral pentoxifylline or oral misoprostol. Insufficient evidence is available for or against recommending the prescription of oral first- and second-generation type-1 histamine receptor antagonists, tricyclic antidepressants, cyproheptadine, aspirin, Chinese herbal therapy, an homeopathic complex remedy, ascorbic acid, AHR-13268, papaverine, immune-modulating antibiotics or tranilast and topical pramoxine or capsaicin. Finally, there is fair evidence against recommending the use of oral arofylline, leukotriene synthesis inhibitors and cysteinyl leukotriene receptor antagonists.

Animal Models of Allergic Diseases

“…In addition, studies evaluating serum histamine concentrations revealed that levels are similar [26] or lower [27] in dogs with AD compared to healthy controls, thus the role of histamine is still under debate. Interestingly, the few studies evaluating the effect of antihistamines, including H4 blockers, have failed to report a beneficial effect [28,29]. In a subset of human patients with AD, genetically inherited skin barrier defects are demonstrable and further skin barrier impairment occurs once sensitization develops and inflammation is triggered [30].…”

An update on the treatment of canine atopic dermatitis

“…Interestingly, insufficient evidence was found to support the use of antihistamines for canine AD in a systematic review. 22 This result may derive from the stringent criteria used in the review. As antihistamines are best used as adjunctive therapy, it is understandable why they would not reach sufficient efficacy to be recommended when they are tested as monotherapy.…”

Recent developments in canine atopic dermatitis: A review

“…Unfortunately, very few of these have proven useful in dogs. Leukotriene receptor antagonists, 5-lipoxygenase inhibitors, and the nonsedating antihistamines have not been shown to be effective in animals (Olivry and Mueller, 2003). Medications such as pentoxifylline and misoprostol may provide some relief in a few dogs (Olivry and Mueller, 2003;.…”

“…Leukotriene receptor antagonists, 5-lipoxygenase inhibitors, and the nonsedating antihistamines have not been shown to be effective in animals (Olivry and Mueller, 2003). Medications such as pentoxifylline and misoprostol may provide some relief in a few dogs (Olivry and Mueller, 2003;. The newest treatments for canine AD such as the calcineurin inhibitors cyclosporin A and tacrolimus are designed to interfere with the action of interleukins and other cytokines.…”

“…It is most commonly associated with IgE antibodies to environmental allergens (Olivry and Mueller, 2003). The exact prevalence of canine AD is not known, but in textbooks, estimates of 3-15% and around 10% (Scott et al, 2001) have been stated.…”