In the context of urticaria, LPS may facilitate mast cell degranulation via Toll‐like receptor 4 (TLR4) resulting in the release of pro‐inflammatory cytokines, while SCFAs may inhibit both IgE‐mediated and non‐IgE‐mediated mast cell activation via anti‐inflammatory Il‐10 and PGE2.26 This evidence concerns the gene IGHE and urticaria.