A double‐blinded, randomized, controlled, crossover evaluation of a zinc methionine supplement as an adjunctive treatment for canine atopic dermatitis

Background Zinc is important for skin health and proper immune system function. Hypothesis/Objectives A zinc methionine, essential fatty acids ( EFA ) and biotin product (Zn supplement) was compared to an EFA and biotin product (control) in canine atopic dermatitis ( CAD ). Animals Twenty seven client‐owned dogs with chronic CAD receiving ciclosporin or glucocorticoids. Methods A 24 week, randomized, double‐blinded, controlled study with crossover at week 12 and 4 week period of allergy medication reduction at weeks 8 and 20. Evaluations included Canine Atopic Dermatitis Lesion Index ( CADLI ), pruritus Visual Analog Scale ( VAS ) and cytology sampling. Results In dogs receiving the zinc supplement and ciclosporin for eight weeks, 44% ( n = 7) had significantly decreased CADLI from 11.9 to 6.0 ( P = 0.0002) with no significant change in pruritus VAS ( P = 1.0). In dogs receiving the zinc supplement and glucocorticoids for eight weeks, 55% ( n = 6) had significantly decreased CADLI from 10.9 to 5.0 ( P = 0.0043) and pruritus VAS from 7.4 to 3.2 ( P = 0.0166). For dogs receiving either steroids or ciclosporin there was a reduction in use of such medications, for at least four weeks, in 63% of dogs receiving the zinc supplement and 37% of dogs receiving the control. This difference was not significant ( P = 0.1027). Seventy eight percent of dogs were diagnosed and treated for superficial skin infections during the study. Conclusions and clinical importance This study supports a potential benefit of adjunctive zinc methionine supplementation in CAD . Dogs receiving glucocorticoids may be more likely to benefit. Further studies are needed to substantiate these initial results.