[Adverse effects of hair care in users].

The panoply of products used by hair care professionals to wash, dye, shape and beautify hair is not entirely free from adverse events. Such effects consist mainly of irritation dermatitis and allergic contact eczema affecting the scalp, as well as the back and front of the neck, the forehead and periorbital areas, and the cheeks. The most frequently cited allergens include paraphenylenediamine (PPD) in hair dyes, glycerol monothioglycolate (GMTG) in acid perm lotions, and ammonium persulphate in hair lighteners (the latter substance being responsible primarily for contact urticaria). However, care should also be paid to other allergens such as cocamidopropyl betaine among surfactants, as well as certain components in hair formulations such as preservatives and fragrances (as well as minoxidil, frequently used by patients).