The use of an alternative ICM has demonstrated to reduce the risk of re-occurrence of hypersensitivity reactions; nevertheless, assessing cross-reactivity and good tolerability of alternatives through skin tests remains the optimal strategy to identify a safer ICM.11 Unfortunately, skin tests maintain a good predictive value only within 2–6 months after the suspected reaction, probably due to IgE rapid clearance. The gene discussed is IGHE; the disease is hypersensitivity reaction disease.