Sensitisation to ethylhexyl salicylate: Another piece of the frontal fibrosing alopecia puzzle

Abstract

Background: There is speculation that some environmental factors may be impacting the increasing incidence of frontal fibrosing alopecia (FFA). In a recent publication, sensitisation to benzyl salicylate was shown to be prevalent among 36 patients with FFA. Ethylhexyl salicylate (EHS), a light stabiliser, ultraviolet (UV) B absorber and UV filter, frequently found in photoprotectors/cosmetics and, rarely reported as a sensitiser, was not patch tested in said research. Methods: From January 2021 to February 2022, 33 patients with FFA were patch-tested with the European Photopatch Series, including EHS 10% pet. in two hospitals. In addition, we conducted a literature review and a market survey. Results: Patch test reactions to EHS were identified in 9 of 33 (27.3%). Four of nine also reacted to their personal sunscreens (containing EHS). All involved women with a mean age of 54 (30–65). Five patients had been diagnosed with FFA before the patch tests; and, four were diagnosed with FFA during the patch test investigations. Conclusion: Sensitisation to EHS was frequently found in a selected population of patients with FFA. We propose to expand the spectrum of contact allergens described in patients with FFA to include EHS and discuss the possible need for optimization of the patch test preparation.