[Anaphylaxis due to excipients: hypersensitivity to polyethylene glycol]

Polyethylene glycols (macrogol) are synthetic polymeric substances that are used as excipients in numerous cosmetic and pharmaceutical preparations because of their stabilizing properties. Immediate allergic reactions to excipients such as polyethylene glycols (PEGs) are rare. The actual prevalence is likely underestimated due to numerous episodes not being recognized. Patients with a PEG allergy often present following multiple episodes of anaphylaxis to structurally nonrelated pharmaceutical drugs and depot formulations such as laxatives. In these cases, excipients should be considered a possible trigger and be examined accordingly by an allergy specialist. The diagnostic options and clinical implications of PEG allergy are illustrated using two case studies.