A protein in skin may explain why cosmetic products cause rashes – and it could help us prevent such allergic reactions (Nicolai et al., 2020).

Annemieke de Jong at Columbia University, New York, and her colleagues wanted to work out why substances in perfumes, toothpaste and skin creams can trigger problems.

Through a series of tests, they discovered that many allergens in them were
able to bind to a molecule in skin called CD1a. This molecule then activates immune system T-cells, which in turn cause an allergic reaction

But the binding to the skin protein is reversible, suggesting allergic reactions could be stopped. “If you could find a way to out-compete these allergens binding to CD1a, there would be no allergic reaction,” says de Jong.

The research was done in a dish, so the next step is to look for a similar response in human skin.

Sara Brown at the University of Dundee, UK, says if these findings lead to a treatment, “it would be a great help to many patients whose skin allergies can currently only be prevented by avoiding what they have become allergic to or by using steroids”.

References

Murugesu, J.A. (2020) Key to Allergic Rash may have Been Found. New Scientist. 11 January 2020, pp.17.

Nicolai, S., Wegrecki, M., Cheng, T-Y., Bourgeois, E.A., Cotton, R.N., Mayfield, J.A., Monnot, G.C., Le Nours, J., Van Rhijn, I., Rossjohn, J., Moody, D.B. & de Jong, A. (2020) Human T cell response to CD1a and contact dermatitis allergens in botanical extracts and commercial skin care products. Science Immunology. 5(43), ppeaax5430. DOI: 10.1126/sciimmunol.aax5430.