Univariate and multivariate analyses showed that preexisting allergic rhinitis, bronchial asthma, antibiotics allergy, past immediate HSRs to ICM during previous CAG, a lower level of eGFR as well as a higher level of Hs-CRP and NLR prior to CAG, CTO interventional CAG, and the application of iohexol are risk factors for the occurrence of AU (P < 0.05 for all variables, Table 3). The gene discussed is CRP; the disease is allergic rhinitis.