User:Echase93

Input in the causes section of the already existing Allergic Rhinitis Wikipedia article.

https://en.wikipedia.org/wiki/Allergic_rhinitis

We would like to add in a subheader for their topic. We would edit it to be "Proximate or acute causes"

Ours would be titled "Probable Underlying Mechanism of Causation."

Hygiene Hypothesis

Main Article: Hygiene Hypothesis

The Hygiene Hypothesis theorizes that a lack of exposure to pathogens within the first year of life increases susceptibility to acquiring allergies. Because evolution has equipped the human body with the necessary defenses to fight off infection, the body has a higher allergic sensitivity to microbes in the environment that otherwise would not be harmful.

The underlying mechanism of the hypothesis is based on the differentiation of Helper T Cells into Th1 and Th2 cells. Early childhood exposure to pathogens stimulates the immune system to differentiate to Th1 cells, better suited to combat pathogens, with a lower ratio of Th2 cells, which causes an the inflammatory response characteristic to allergic rhinitis.

Studies who observed children living on a farm or in a big household, discovered that those children had a decreased risk of developing allergies. This was associated with an increase in TH1 and a decrease in TH2. The explanation behind this result is because those children are constantly exposed to a greater diversity of organisms and bacteria, due to the environment that they live in. A more recent study in 2016 reaffirmed these findings with an experiment that showed children who grew up in affluent families had higher levels of TH2 cells. They had acquired more allergies later in life when compared to children who had grown up in low socioeconomic states. Their findings suggested that more affluent families have less exposure to various types of bacteria.

Resources