Mast cells have long been associated with AD, and increased numbers are found in the skin of atopic patients.16 Upon activation by cytokines, FcεRI‐bound IgE, or pathogen‐ and danger‐associated molecular patterns, mast cells can release large amounts of pro‐inflammatory mediators, such as tumor necrosis factor (TNF).17, 18 Furthermore, increased numbers of group 2 innate lymphoid cells (ILC2) in the skin of Flgft/ft mice and patients with mutations in FLG11 suggest a central role for ILC2 in genesis of skin inflammation in this model. The gene discussed is IGHE; the disease is dermatitis.