Allergies triggered by 'insults' to body

ALLERGIES such as asthma have become the most common environmental illnesses of Western countries and their frequency continues to grow, scientists report today.

An explosion of environmental 'insults' to a part of the body's immune system designed to fight parasites has led to a doubling of many serious allergies over the past decade, and pharmaceutical companies need to rethink the way they design drugs to combat them, they say.

Hannah Gould, professor of biomedical sciences at King's College London, said that atmospheric pollutants, house dust mites, pollen, foods and fungal spores are some of the principal reasons behind the rise.

The growth of allergies in the young has been particularly marked, with asthma now affecting about one in 10 children compared with about one in 20 adults, she told the Independent.

Professor Gould and her colleague Brian Sutton say in the journal Nature that the most common allergies are asthma, hay fever, skin rashes and reactions to food.

'Allergy in one form or another afflicts more than 20 per cent of the population, and the alarming increase in its prevalence, morbidity and mortality over the past decade has led to its designation as the number one environmental disease,' they say.

Allergies are particularly debilitating because they trigger inflammation, itching, coughing, wateriness of the eyes and nose, breathing problems, vomiting and diarrhoea, the researchers say.

Scientists say a type of antibody called IgE is implicated in triggering these reactions in skin, lungs and gut. They believe the antibodies evolved against parasites invading the body but are now prone to a growing number of environmental irritants.

'There is a big suspicion that pollution in the atmosphere exacerbates the tendency of the body to produce IgE antibodies . . Existing drugs are not adequate to control allergies and drug companies are desperate to develop better ones,' Professor Gould said.

One line of attack is to stop IgE antibodies binding to the cells lining the nose, lung and gut that release the substances that trigger the reactions, she said.