ABSTRACT
Background: Polyethylene glycol (PEG) and polysorbate are two commonly used excipients in cosmetics, therapeutics, and processed foods. They are used not just to stabilize and preserve but also to influence the pharmacokinetics and bioavailability of the active ingredients of these products. Numerous reports have described patients with recurrent urticaria self-reporting multiple unrelated products hypersensitivities. We aim to describe a case series of sensitization to PEG in patients with recurrent urticaria and its implications to the currently available COVID-19 vaccines in Malaysia. Method(s): Data of all patients during the peak vaccination period (March 2021 -May 2021) who had positive intradermal test to surrogate PEG and polysorbate 80 were retrieved and analyzed. They were tested with PEG 4000 (macrogol), PEG 400 (Systane Ultra eye drop) and polysorbate 80 (Tween 80). Result(s): A total of eight patients were skin test positive to PEG and/ or polysorbate 80. The mean age was 35.1 +/- 10.5 years. Only one patient was male. Everyone reported history of multiple product reactions with recurrent urticaria as the major symptom. Majority (75%) had multiple unrelated products hypersensitivities. Four of them had urticarial reactions after the first dose of mRNA vaccine. Two patients were skin test negative to the lower molecular weight PEG 400. Cross sensitization between PEG 4000 and polysorbate 80 was 100%. All patients were subsequently inoculated with two doses of inactivated virus COVID-19 vaccine without any serious sequalae. Conclusion(s): The validity of skin testing towards PEG is not yet clear. Nonetheless it is a promising tool in diagnosing PEG sensitization in selected patients reporting recurrent urticaria with multiple unrelated products. Pretesting of this select group may be considered before the inoculation of PEG-containing COVID-19 vaccine.