IL13 and atopic eczema: As previously reported (Chan, 2018; Howell et al., 2009; Nuttall et al., 2014), the increase in serum IL‐4 and IL‐13 concentrations in dogs with atopic dermatitis in this study may indicate that the cytokine response to allergens in atopic dermatitis caused by environmental allergens in dogs is mainly mediated by IL‐4 and IL‐13.