Fragrances and colorings are part of what makes soaps attractive, but they're also a potential hazard for people with sensitive skin -- even when they come from natural plant extracts and essential oils. Because it doesn't have the same protection that normal skin does, sensitive skin can also be more vulnerable to certain allergens in fragrance. Where the epidermis and lipid coatings (the layer of dead cells and the oil that protect you) are thin, it's easier for foreign substances to enter the body. Since many allergies can be created through repeated exposure to certain irritants, problems may develop from using cleansers that contain them. Here are a few to watch out for:
Soaps with fragrances also can be more of a problem in geographical areas with higher mineral content in the water, which makes it harder to build up and rinse off lather. Soap residue on the skin can then leach into the body over a long period of time, increasing sensitivity to allergens.