According to a recent survey, childhood allergies such as hay fever, eczema and asthma are on a continual and concerning rise all around the world. Out of these types of allergies, asthma proves to be the most dangerous, being responsible for the greatest number of kids who miss school, become hospitalized and even die.

Asthma is a respiratory and inflammatory disorder, usually of an allergic origin, characterized by the constriction of the air passages within the lungs. Asthma symptoms consist in shortness of breath, wheezing, intermittent cough, chest tightness etc.

The Study of Asthma and Allergies in Childhood survey carried out in 1991 was repeated in 2002 and 2003. Comparing the results of the 1991 survey with the ones obtained in 2002 and 2003, researchers found that the prevalence of childhood allergies increased in 56 countries.

In the study, scientists investigated parents of 193,000 children of 6-7 years of age and 305,000 children aged 13-14 from countries all around the world, such as Canada, Sweden, Brazil, South Africa, Iran etc.

Researchers found that in England asthma prevalence rose from 18.4% to 20.9%, hay fever rose from 9.8% to 10.1%, while eczema prevalence went up from 13% to 16% from 1991 to 2003. The main causes which led to this increase in allergies prevalence were linked by experts to airborne triggers, such as air pollutants, exposure to bacteria early in life, unhealthy diet and lifestyle etc.

"The data have direct relevance for health-service delivery in the countries included, as well as providing a basis for understanding these disorders. In almost all centers, there was a change in prevalence of one or more disorders over time."

"Although changes in mean annual prevalence to the order of 0.5 percent might sound small, such changes could have substantial pubic health implications, especially since the increases took place most commonly in heavily populated countries," stated Professor Innes Asher of the University of Auckland, New Zealand, who led the study.