Our findings establish a causal relationship between specific gut bacteria (Eubacterium eligens group) and atopic dermatitis risk while identifying seven key bridging genes (AKR1C2, GALE, GGH, NR4A1, PLA2G4B, TYMS) that connect gut microbial metabolites to skin pathology. Here, AKR1C2 is linked to atopic eczema.