Indeed, overexpression of MRGPRX2 and/or increased numbers of MRGPRX2+ MCs have been described in the lesions of patients with MC-driven disorders, e.g., cutaneous mastocytosis (13), chronic spontaneous urticaria (CSU) (15), and chronic prurigo (23), and correlated with disease severity in the latter. This evidence concerns the gene MRGPRX2 and cutaneous mastocytosis.