Polyethylene glycol as marker for nitrofurazone allergy: 20 years of experience from Turkey

Background. Polyethylene glycols (PEGs) and propylene glycol (PG) are used as vehicles in various medicinal and cosmetic products. They are potential contact sensitizers, including low molecular weight PEGs in nitrofurazone preparations that are still widely used in Turkey. Objectives. To investigate the prevalence of allergic contact dermatitis caused by PEG and PG in a relatively large group of patients in Turkey. Methods. In this retrospective, cross-sectional, single-centre study, 836 patients patch tested with PEG and PG between 1996 and 2015 were reviewed. Results. Thirty-five patients (4.2%) showed positive patch test reactions to PEG, and 7 (0.8%) showed positive patch test reactions to PG, partly as late positive reactions with PEG. PEG sensitivity was almost exclusively related to nitrofurazone allergy. Patch test reactions to PG were currently relevant mainly with regard to the use of minoxidil, and antiherpetic or corticosteroid creams. Ten patients (25%) had concomitant contact allergies to various topical drugs containing mainly PEGs. Conclusions. PEG sensitivity seems to be a marker for contact allergy to topical nitrofurazone in Turkey. Nitrofurazone allergy appears to favour concomitant sensitization to PEG. We would suggest the inclusion of PEG in an extended baseline patch test series in Turkey. Late patch test readings are important to diagnose delayed positive reactions to PEG.