A case of acute contact dermatitis induced by formaldehyde in hair-straightening products.

Conflicts of interest: The authors have declared no conflicts of interest. by hairdressers to straighten curly hair, have recently become fashionable in hair salons. They are generally based on formaldehyde, which alters hair keratins in order to provide a smoothing effect on frizzy hair. The treatment process usually includes three tasks: (i) applying the product to the hair, (ii) blow-drying the hair, and (iii) heat-treating the hair (generally with a flat iron). However, hair straightening products may produce extremely severe allergic