Safe Administration of SARS-CoV-2 Vaccine After Desensitization to a Biologic Containing Polysorbate 80 in a Patient With Polyethylene Glycol-Induced Severe Anaphylaxis and Sensitization to Polysorbate 80

Polyethylene glycols (PEGs) and structurally related polysorbates (PEG sorbitans) are polyether compounds derived from ethylene oxide that are widely used as excipients and conjugated pharmaceuticals. The role of PEG as an unsuspected, high-risk 'hidden" allergen that can cause systemic allergic reactions was recently assessed. In November 2020. a 61 year-old man developed a >c\cic allergic reaction to a PEG-based colonoscopy preparation containing PEG 3350 (Moviprep). Immediately after taking the drug, he experienced generalized urticaria with labial angioedema. vomiting, dysphagia, presyncope. hypotension, and tachycardia. He was treated with intravenous fluids, metoclopramide 10 mg, methylprednisolone 40 mg. and dexchlorpheniramine 5 mg. His condition barely improved, and he was treated in the emergency room with a second dose of the same drugs together with intravenous hydrocortisone 200 mg. His symptoms resolved completely. It should be noted that despite the severity of the reaction, epinephrine was not administered. The patient reported that he had previously developed pruritic erythematous macules when using some shower gels. In January 2021, an allergy work-up was carried out in the allergy department. Skin prick tests (SPTs) performed with undiluted Moviprep and PEG 2000 (0.16 mg'mL) yielded positive results (wheals of 7·7 and 4·5 mm, respectively).