An analysis of hair dyes available on the Polish market with regard to the presence of ingredients with known sensitizing potential

Introduction
Hair dyes are a known source of substances that cause allergic reactions. In spite of abundant literature on this topic, there is still a lack of analyses whether different colors of hair dyes are connected with various levels of risk of sensitization.

Aim
An analysis of hair dyes from different color groups available on the Polish market with regard to the presence of ingredients with known sensitizing potential.

Material and methods
Declared contents of 100 black, brown, red, ginger and blonde hair dyes, each 20 products, were analysed for the presence of ‘problematic’ dyes, preservatives and fragrances, listed in the Cosmetics Directive (Annex II and III), as ingredients allowed with limitation due to their sensitizing or irritating potential.

Results
Among 291 unique ingredients present in the analysed hair dyes, 78 (26%) deemed as problematic, including 46 dyes, 14 preservatives, 16 fragrances (2 substances were both preservatives and fragrances). The most frequent problematic dyes were resorcinol (65%) and meta-aminophenol (63%). Blonde hair dyes contained the same dyes as in brown and black colors. The most frequent ‘problematic’ preservatives were sodium sulfite present in 56% of all analysed products and sodium metabisulfite (29%). Almost each hair dyes product (92%) contained compositions of undisclosed fragrances hidden under a general cryptonym Parfum/Fragrance. Significant differences in the content of ‘problematic’ substances in particular color groups were found only for dyes (p = 0.0018). There were no statistical differences in the number of fragrances and preservatives among particular color groups. The number of ‘problematic’ dyes was highest in ‘brown’ and ‘black’ hair dyes and lowest in the ‘red’ hair dyes. In two hair dyes ‘ortho-aminophenol’ was declared in the list of ingredients despite being prohibited in cosmetic products.

Conclusions
No hair dye products are free from problematic substances. Potential sensitizers in these products are dyes, followed by fragrances and preservatives. Hair dyeing always carries the risk of allergic reactions, also when dying hair to blonde shades.