New research that suggests the way some chemicals displace natural fat-like molecules known as lipids in skin cells may explain how many common ingredients trigger allergic contact dermatitis.

The breakthrough could help stem soaring cases of rashes, lumps, blisters, itchy eyes and facial swellings. It has been dubbed the “molecular missing link​” because it might have brought a new way to treat the condition.

Currently, the only way to stop allergic contact dermatitis is to identify and avoid coming into contact with the chemical that causes the reaction.

Most allergies are attributed to proteins or synthetically produced peptide antigens that set off the immune system.

But chemicals found in personal care products are different kinds of molecules that were not thought to be able to directly elicit a reaction.

Topical ointments can help soothe the rashes, and oral corticosteroids may be prescribed for severe cases, although these can increase the risk of infections and other side effects.

The newly reported discovery raises the possibility that allergic contact dermatitis could be prevented by applying lipids to the skin that compete with and displace those triggering an immune reaction.

Jamie Rossjohn, a professor of biochemistry and molecular biology at Monash University in Melbourne, was part of a team of international researchers investigating the role an abundant protein in the skin known as CD1a could play in allergic reactions to cosmetics.

“Normally, many CD1a molecules are filled with natural blockers in our bodies that would prevent an exaggerated immune response, and those small compounds basically remove those natural blockers​” he said.