One in every 13 children are affected by allergies and those numbers are on the rise and increased by 50 percent between 1997 and 2011. The majority of allergic reactions are caused by eight foods: milk, eggs, peanuts, tree nuts, soy, wheat, fish and shellfish and in children under 18, these foods cause about 300,000 ambulatory-care visits each year. In a day and age where good medical care is available to so many why are allergies increasing?

One explanation for this phenomenon is the “hygiene hypothesis,” which states that a lack of exposure to infectious agents in early childhood causes the immune system to mistake some food protein as harmful bacteria. Many physicians, and the FDA, believe this idea has some merit, and further research is being done on the matter. Additionally, the overuse of antibiotics and acid-reducing stomach medication causes the gastrointestinal tract to alter, which results in more health issues.

Environmental issues are another contributing factor being credited with causing the increase in allergies. According to climatologists, 2000-2009 was the hottest decade on record in the United States, and this warmer climate may cause worsened respiratory allergies, as the higher temperatures increase the growing season for plants and, in turn, the production of pollen and allergen counts.

Yet another cause can be attributed to mothers, who pass genes on to their children during pregnancy. The various factors that a baby is exposed to in utero may have a huge impact on childhood. Even simple factors, such as what a mother eats, could have an impact on whether her child eventually develops allergies. A study called the EuroPrevall Birth Cohort Study was launched in 2005, and it aims to study the effects that environmental changes, genetics and infections have on the development of allergies. This study is considered to be the most comprehensive investigation of allergies that has been conducted as of yet.  

While no specific cause has been identified to solve the large puzzle of allergies, smaller pieces are being discovered which are helping doctors all over the world slowly start to see the whole picture.