Allergic contact dermatitis caused by dexpanthenol-Probably a frequent allergen

Background: Panthenol (synonym: dexpanthenol), the alcohol analogue of panthothenic acid, is frequently included in moisturizers, wound-healing agents, and other cosmetics, and has been shown to be responsible for allergic contact dermatitis (ACD). Objectives: To evaluate the frequency of ACD caused by dexpanthenol, and to characterize reactive patients. Methods: We retrospectively reviewed the files of patients patch tested between 2009 and 2017 in the Department of Dermatology of the Coimbra's University Hospital and describe patients who reacted to dexpanthenol 5% pet., tested initially in a cosmetic/vehicle series and in the last 3 years in consecutive patients. Results: Among 2171 patients, 26 (1.2%) had positive patch test reactions to dexpanthenol, mostly patients tested for chronic eczema (88.5%, n = 23), either widespread (5), or localized to the hands (5), face (4), or legs (7). Relevance could be traced in 20 patients (76.9%), related to the use of Bepanthene cream (15), moisturizers (3), topical medications (1), and a shampoo (1). Twenty-five of 26 patients (96.2%) reacted to several other allergens, mostly ingredients of cosmetic or pharmaceutical products. Conclusions: Although ACD caused by dexpanthenol is considered to be rare, it may be frequently overlooked. As we found a relatively high frequency of relevant cases, in agreement with a previous study, the inclusion of dexpanthenol in patch test series, at least in cosmetic and topical drug series, is encouraged.