MRGPRX2 and atopic eczema: In addition, mast cells in the skin express MRGPRX2, which mediates diseases, such as rosacea, atopic dermatitis, nonhistaminergic itch, and pseudoallergy (Roy et al., 2021) and MRGPRX2 is involved in the majority of peptide stimulation-associated activation in human mast cells (Lu et al., 2017).