We noted that the response to oral agents and a low-histamine diet among those with CU was associated with a number of biomarkers and factors, including age, sex, duration of the disease, concomitant angioedema, a phenotype of dermatographism, the presence of long-lasting wheals, DAO, Hct levels, ESR levels, eosinophil count, IgE, ANA, and a history of exacerbation when a particular food was consumed. This evidence concerns the gene IGHE and angioedema.