Skin reactions to propylene glycol

Propylene glycol (PG), ethylene glycol (EG), and polyethylene glycol 400 (PEG 400) were tested, as is, in a total of 1,556 cases of eczema using the chamber test method. All the year round, the number of positive reactions to PG was 12.5% to EG 4.9%, and to PEG 400 0.3%. A total of 30% of the positive reactions to PG were allergic in appearance. Also the new fatty alcohol-PG bases of Metosyn ointment and Topilar ointment as well as Metosyn ointment (fluocinonide) itself provoked reactions in a great number of patients with positive reactions to PG, as is. The reactions to PG were considered to be truly allergic in four cases. In them, positive reactions were elicited by testing with high dilutions of PG and by applying the glycol in the patients' armpits as an open test. It is concluded that PG and topical preparations containing it in high concentrations should not be used with occlusion, and that allergic reactions must be watched.