Allergy history to beta-lactam antibiotics is important to consider when selecting SAP, although most patients who sustain an anaphylactoid response (immunoglobulin (Ig)E-mediated, such as anaphylaxis, urticaria, bronchospasm, or angioedema; non-IgE-mediated, including Stevens–Johnson syndrome, toxic epidermal necrolysis, or other drug-induced cutaneous hypersensitivity reactions) to a beta-lactam report no prior history. This evidence concerns the gene IGHE and toxic epidermal necrolysis.