Some compounds found in many personal care products displace natural fat-like molecules in skin cells, which may explain how they cause an allergic skin rash.Study explains why some creams and cosmetics may cause a skin rash — Skin Care News — ScienceDaily
This is a great explanation to why some products cause skin sensitivities and rashes whereas other products might not. This realm of science is something that’s not be fully understood.
Our skin produces oils that act as a protective barrier against allergens. We’ve known that for quite some time. There are studies dating back to the 1950s looking at the protective effect of our natural sebum production and skin health.
What Science Daily is reporting on is something more novel. The idea is that some skin care products displace our natural lipids allowing the allergen to come into direct contact with the skin which then allows our immune system to recognize the allergen and produce an immune response, making it a contact allergen. The reason this is kinda cool is that the treatment gets a lot easier. In theory the application of a competing lipid to reestablish that barrier may be all that is needed to alleviate the sensitivity.
There is some science to back up this claim, especially when looking at patients with psoriasis, which flare ups can be triggered by contact allergens. One of the treatments is thicker moisturizers with some people going so far as using vaseline or other petroleum jelly.
The products tested that showed an allergen inducing properties were farnesol, benzyl benzoate, and benzyl cinnamate. Farnesol is found most commonly in fragrances, lipstick, and foundations. Benzyl benzoate is very common in skincare and cosmetics. Benzyl cinnamate is mostly found in fragrances. If you have a contact skin sensitivity with products it might be worth looking at that ingredients list to see if these three ingredients are on that ingredients list.
Limitations: this was not a clinical, double blind type study. It was conducted on tissue cultures which is one of the first steps before going to human trials.
YAY! Science in skin care!