The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor known to mediate the toxic and biochemical effects of polycyclic aromatic hydrocarbons (PAHs) in environmental pollutants, that are under suspicion to foster atopic dermatitis (AD). In this study, we identified AKR1C3, a NAD(P)H-dependent oxidoreductase, is known to be up-regulated in atopic dermatitis (AD) lesion, as a target gene of AHR. We found that treatment of HaCaT keratinocytes with benzo[a]pyrene (BaP) induces the expression of AKR1C1 and CYP1A1 (a marker gene for AHR activation) in a dose- and time-dependent manner. SDS-PAGE/western blot analyses confirmed that the observed transcriptional changes were translated to the protein level. Chemical and genetic inhibition of AHR abrogated the BaP-mediated induction of AKR1C3 and CYP1A1 mRNA and protein, providing evidence that AKR1C3 is regulated by AHR signaling. 3-dimensional culture was performed with or without BaP or AKR1C3 inhibitor and assessed barrier functions by immunohistochemical staining. Finally, we investigated a correlation between AHR, AKR1C3 and filaggrin/loricrin expression in skin samples obtained from 35 AD patients by immunohistochemistry, supporting a role of AHR and AKR1C3 in AD pathogenesis. Overexpression of AKR1C3 causes down-regulation of Loricrin. Decrease of skin barrier proteins including loricrin is considered as a key event in the pathogenesis of “non-genetic” AD. Dysfunction of the epidermal barrier allows external allergens to invade the skin and induce immunological sensitization thereby causing Th2-triggered inflammation. This finding seems to contribute to the mechanism of AD pathogenesis caused by air pollution.