Cases of asthma and allergic diseases are increasing worldwide, not just in low and middle income countries but in developing countries, including the United States, as well. Furthermore, studies have shown the incessant increase in the complexity and severity of allergic diseases and asthma especially in children and young adults. For instance, a study conducted by the Centers for Disease Control and Prevention, food allergies among children increased by approximately 50% between 1997 and 2011. Meanwhile, for every 12 people in the United States, at least one is suffering from asthma. That is about 25 million people. From 2001 to 2011, the CDC claims that the number of Americans suffering from asthma rose by 28 percent, and the greatest rise in rates of asthma was among children.
The rise in asthma and allergy rates is observed due to many factors. First, it has been theorized that too much cleanliness could be the blame. The “hygiene hypothesis” proposes that children are insusceptible to dirt, bacteria, and other infectious agents early on, and their under-stimulated immune systems goes on the offense when subjected to benign stuff such as food. Previous studies have shown that children in day cares, known as nests for spreading germs, suffer from fewer allergies than those raised in homes with limited contact with other kids. However, there is still no proof as to the validity of the hygiene hypothesis.
Another factor that could also be contributing to the allergy increase is the rise in carbon dioxide levels in the atmosphere. The third one to consider is smog and other types of air pollution. A test tube experiment has given sufficient evidence for the link between pollution and allergies, however it has remained difficult to prove in large populations. Moreover, climate change, change in ambient temperatures have caused diverse consequences on human health, including the trigger of allergies and asthma.
Although several factors have been enumerated, the real culprit for allergies depends on the symptoms specific to each individual person.