PPARα ligands have been widely shown to have anti-inflammatory effects by regulating the keratinocyte activation observed in various types of dermatitis, including irritant and allergic contact dermatitis, atopic dermatitis, and ultraviolet (UV)-induced erythema (Sheu et al., 2002; Dubrac and Schmuth, 2011; Shin et al., 2016). This evidence concerns the gene PPARA and allergic contact dermatitis.