The world is becoming increasingly allergic to common foods, with children in particular likely to develop new allergies. When analysed on a global basis, the spread of allergies is far from even, with Western nations increasing at a much faster rate and specific countries much worse than others. While no-one knows for sure why allergy rates are increasing, a number of theories are being examined to explain the rising allergy crisis.

Allergies are caused by a reaction of the immune system as it responds to environmental substances. While the immune system is supposed to identify harmful substances as a form of protection, sometimes, it also reacts to substances that are harmless to most people. This can occur in response to a range of stimuli, from foods and flowers through to pets and medicines. While asthma is not strictly an allergy, it often has similar symptoms and underlying causes.  

Allergy rates are rising across most of the Western world. According to research from the US Centers for Disease Control and Prevention, food allergies in American children increased by 50 percent between 1997 and 2011, and now affect almost 8% of children. The situation is even more pronounced in Australia, which has one of the worst food allergy rates in the world at 9%. While food allergies also affect 7% of children in the UK, interestingly, they only affect 2% of children in Europe.

If these allergy rates weren't worrying enough, consider just how quickly some of them have grown over the last 20 years. According to the National Center for Biotechnology Information (NCBI), there was a 500% increase in peanut allergies in the UK between 1995 and 2016. In other NCBI studies, 9% of all Australian one-year-olds had an allergy to eggs, and 3% had a peanut allergy. This increased sensitivity to food is probably related to Western lifestyles and environmental factors prevalent in modern Western societies. 

According to the American Academy of Allergy Asthma and Immunology (AAAAI), one leading theory behind rising allergy and asthma diagnosis rates is known as the "hygiene hypothesis." Basically, this theory suggests that the Western world is too clean, with people not exposed to enough germs and immune systems failing to differentiate between harmful and harmful irritants. There may also be other issues at play, however, with pollution, medication, and dietary factors also likely to have an effect.

According to AAAAI, there is some research linking antibiotics and acetaminophen with a rise in allergy and asthma rates. Obesity may also have a contributing factor, with Western nations that experience high levels of food allergies also experiencing high levels of obesity. The delayed introduction of allergenic foods like eggs and nuts can also cause problems, with Western parents sometimes causing harm in an attempt to protect their children from certain foods.

Altered gut bacteria can also affect how the body responds to allergens, and once again, this may be closely related to dietary factors and widespread antibiotic use. Last but not least, there may be a link between vitamin D and allergies, with children who spend more time indoors possibly developing a compromised immune system over time. All of these factors are likely to have an impact, with children who grow up isolated from the world around them less likely to develop healthy immune system responses.