Researchers from the Chinese University say they’ve made a key breakthrough in the study of how cockroaches cause allergic reactions, opening the way to specific treatments for the conditions.

Previously, the only way to stop the effects of a cockroach allergy was to avoid exposure to them, but the CUHK team say their discovery of seven novel allergens found in the creatures will pave the way for targeted immunotherapy treatment.

In a study conducted over the past three years, experts from the university’s medical department found that cockroaches are the second most common trigger for allergic diseases, such as asthma and eczema.

Previously, 13 cockroach allergens had been identified, but the team used its expertise in genomics and allergies to identify a further seven, creating a comprehensive guide to exactly what allergens people are affected by.

Professor Leung Ting-fan, who led the study, said the discoveries represented a big change for patients.

"The treatment for cockroach allergy was to avoid the exposure, mainly because we did not know exactly the full spectrum of allergens that patients are allergic to," he said.

"But now we have this high-resolution allergen mapping, we know exactly what cockroach allergens patients are allergic to, and then we can decide the proper targeted immunotherapy treatment."

Exposure to dust containing cockroach allergens can cause conditions such as asthma, while the allergens can also find their way into food, causing symptoms of food allergies. ¬

Dr Patrick Chong, a specialist in paediatric immunology, allergy and infectious diseases, explained how immunotherapy treatments can help patients.

"It's a kind of re-education of the immune system, to let it get used to the allergen gradually, but it takes time... at least for three years," he told RTHK.

Chong said some patients do not know the triggers of their allergic disease, but identifying the potential allergens can improve the situation.

"Like for patients with asthma, if they are really related to certain kinds of environmental allergens and if they avoid it, their disease control will be much better," he told RTHK. "If they cannot avoid those potential allergens, like dust mites, there is another way to achieve a potential cure, which is immunotherapy."