Allergy to 3-nitro-p-hydroxyethylaminophenol and 4-amino-3-nitrophenol in a hair dye

Contact allergy to 3-nitro-p-hydroxyethylaminophenol in a hair dye is described for the first time. p-Phenylenediamine is the most common screening allergen when allergic contact dermatitis is suspected, but sometimes the allergen is not sufficient for diagnosing allergic contact dermatitis to hair dyes. A 50-year-old woman developed a severe scalp dermatitis and developed vesicular hand eczema for the first time in her life. Patch testing was performed with the European Standard Series. The patch testing was supplemented with a local series of cosmetic allergens and the hairdresser's series. At the initial patch testing, there was a + reaction to nickel and a +? to PPD at days 3 and 7. Further, she reacted with a +? to her own hair collected at day 3 after the hair dying which elicited the dermatitis reaction. Open exposure to the product, which had initiated the dermatitis, was negative both before and after the allergic reaction to the product. None of the screening chemicals in the hairdresser's series gave a definite positive reaction. Only by patch testing with the individual hair dye product ingredients, the patient's reactions were explained. The patient gave a positive patch test to 4-amino-3-nitrophenol and 3-nitro-p-hydroxyethylaminophenol at days 3-4 reading.