Together with IL-33, thymic stromal lymphopoietin (TSLP) is widely recognized as a critical factor in allergic disorders, including rhinitis, asthma, food allergy, eosinophilic esophagitis, and atopic dermatitis (AD), i.e., conditions, in which MCs act as critical effector cells [31,32,33,34,35,36]. This evidence concerns the gene TSLP and atopic eczema.