PPD stands for paraphenylenediamine, which is a chemical substance commonly found in permanent hair color and other dyes. PPD is used in hair dye because it is a permanent dye that gives a natural look, and the dyed hair can also be shampooed or permed without losing its color. PPD hair dye is used in both salon and at-home color because it is an effective ingredient in coloring dark hair. However, PPD has a reputation for negative side effects, and it can cause reactions ranging from mild skin irritation to more severe allergic contact dermatitis. Sensitive individuals may experience dermatitis, which is skin inflammation and irritation commonly referred to as eczema. Anyone who is planning on coloring their hair should complete a patch test following recommended directions in the packaging to determine their sensitivity with the product to avoid potential allergic reactions, and hairdressers should always use gloves when working with hair color containing PPD. Alternatives to PPD are available, such as semi-permanent hair dyes, metallic hair dyes, and vegetable rinse hair dyes, but these do not provide permanent hair color.