TAC1 and atopic eczema: The co‐citation cluster analysis showed the most popular terms in the field of itch research by hierarchical cluster labels, including 0# atopic dermatitis, 1# intradermal serotonin, 2# chronic pruritus, 3# mechanical itch, 4# gastrin‐releasing peptide, 5# substance p, 6# interleukin‐31 receptor, 7# histamine‐induced itch, 8# bile acid, 9# scratching behavior, and 10# h‐4 receptor.