Certain Lipids in Skin Cells May Explain Common Allergic Reactions to Creams, Cosmetics

A new study suggests the way some chemicals displace natural fat-like molecules, or lipids, in skin cells could explain how many common ingredients trigger allergic contact dermatitis. Led by researchers at Columbia University Irving Medical Center, the Brigham and Women’s Hospital, and Monash University, the study result suggests a new way to treat the condition.

An allergic reaction starts when the immune system’s T cells recognize a chemical as foreign. Since the T cells do not directly recognize small chemicals, new research suggests that these compounds need to undergo a chemical reaction with larger proteins in order to make themselves visible to T cells.

Annemieke de Jong, PhD, assistant professor of dermatology at Columbia University Vagelos College of Physicians and Surgeons, aimed to discover if CD1a, a molecule that is rich in Langerhans cells, might be responsible for making these chemicals visible to T cells. The study found several common chemicals known to trigger allergic contact dermatitis were able to bind to CD1a molecules on the surface of Langerhans cells, and activate T cells by analyzing human cells in tissue culture.

These common chemicals included Balsam of Peru and farnesol, which are found in many personal care products such as skin creams, toothpaste, and fragrances. The researchers also identified benzyl benzoate and benzyl cinnamate as the chemicals responsible for the reaction. Overall, more than a dozen small chemicals were identified as shown to activate T cells through CD1a.

“Our work shows how these chemicals can activate T cells in tissue culture, but we have to be cautious about claiming that this is definitively how it works in allergic patients,” de Jong said in prepared statement. “The study does pave the way for follow-up studies to confirm the mechanism in allergic patients, and design inhibitors of the response.”

A recommendation for treating allergic contact dermatitis is to apply complete lipids to the skin to displace those triggering the immune reaction.

The only present way to stop allergic contact dermatitis is to identify and avoid contact with the offending chemical, along with using topical ointments to soothe the rashes.

In a severe case, physicians may prescribe oral corticosteroids, which increases the risk of infections and other side effects.

REFERENCE

Study explains why some creams and cosmetics may cause a skin rash. Columbia University Irving Medical Center. https://www.cuimc.columbia.edu/news/study-explains-why-some-creams-and-cosmetics-may-cause-skin-rash. Published January 3, 2020. Accessed January 16, 2020.