Résumé
Background: Hair dye is one of the most common causes of allergic contact dermatitis. The main allergen has been identified as para‑phenylenediamine. To prevent the recurrence of contact dermatitis to para‑phenylenediamine, patients should discontinue the use of para‑phenylenediamine‑containing hair dye products. However, many patients are unable to discontinue their use for cosmetic or social reasons. Sometimes, they continue to have symptoms even after switching to so‑called “less allergenic” hair dyes. Objectives: To evaluate the safety of 15 commercially available hair dye products in patients with allergic contact dermatitis due to para‑phenylenediamine. Methods: We performed patch tests using 15 hair dyes that were advertised as “hypoallergenic,” “no para‑phenylenediamine” and “non‑allergenic” products in the market. Results: Twenty three patients completed the study and 20 (87.0%) patients had a positive patch test reaction to at least one product. While four (26.7%) hair dye products contained para‑phenylenediamine, 10 (66.7%) out of 15 contained m‑aminophenol and 7 (46.7%) contained toluene‑2,5‑diamine sulfate. Only one product did not elicit a positive reaction in any patient. Limitations: Small sample size and possibility of false‑positive reactions. Conclusions: Dermatologists should educate patients with allergic contact dermatitis to para‑phenylenediamine about the importance of performing sensitivity testing prior to the actual use of any hair dye product, irrespective of how it is advertised or labelled.