Permanent hair wavings: What dermatologists should know?

Hair represents an important aspect of human individuality. The possibility of having an easy to handle hairstyle and changing it from time to time promoted an increasing search for chemical hair transformations, including permanent wavings (PW). PW is the chemical process used to convert straight into curly hair. Significant findings have been made in this field within the last three decades. In the past few years, PW has come back up to date, helping to define curls in wavy and curly hair and to create waves in straight hair. "Afro permanent" and "Beach waves" are some popular names for these new uses of PW. The primary safety concerns for PW generally arise from misuse or failure to comply with the product's usage instructions. Skin irritation, hair breakage, oral toxicity, sensitization, and scarring alopecia have been reported in the literature. Therefore, dermatologists need to understand well this matter to properly advise patients on how to get the best outcome without hazards. This review aims to discuss the main types of reducing agents used, the different techniques, the consequences to hair shafts, and the most important patients' recommendations on this topic.