Just What are Allergies?

What are allergies, and why do they exist? Why do some people get allergies, while others don't? Why are some allergies, such as peanut allergies, more common than others, such as an allergy to salt?

Allergies are caused by none other than our beloved immune system. The immune system creates antibodies for most things that enter our bodies, just in case. Most of these antibodies are never used, since the corresponding "invader" is harmless. However, mistakes can be made. For example, let us take the harmless peanut. Unfortunately, the peanut protein has a similar structure to that of a parasite. For this reason, the immune system often mistakes the peanut for a parasite. When assigning antibodies, it gives peanuts the parasite antibody instead of the peanut antibody. Whereas the peanut antibody does nothing, the parasite antibody will do anything in its power to kill the parasite. These misassigned antibodies attach to mast cells, where they lie in wait. The next time a peanut enters the body, it is recognized as a parasite and the mast cell explodes. These mast cells produce large amounts of histamine, which causes inflammation and the normal symptoms associated with allergies. Anti-allergy medications are antihistamines, since they neutralize the histamines produced by mast cells and stop the inflammation and allergic symptoms. In certain situations, the body has an extreme reaction to an allergen. The allergen spreads through the body, activating mast cells throughout the body. This leads to every mast cell exploding with histamine, causing widespread inflammation. This is called anaphylactic shock. Anaphylactic shock can block airways, making it hard to breathe. Every part of the body gets inflamed. Naturally, the body produces epinephrine, or adrenaline to combat the anaphylactic shock. Oftentimes, this is not enough. Luckily, humans have created epi-pens, which literally stand for epinephrine pens. Epi-pens flood the body with adrenaline, reducing the effects of anaphylactic shock and preventing death. Nobody knows why some people develop allergies, while others don't. In fact, some people don't have any allergic reaction to a substance until late in life, when an allergy can suddenly develop. However, we do know why some substances are more likely to cause allergies than others. Invaders that have protein structures similar to parasites, such as peanuts or pollen, are more likely to be mistaken for those parasites. These foods are the most common allergens.

Humans have developed several technologies to combat allergies. As discussed, we have antihistamines, which shut down the histamine response in our body. These include medicines such as Allegra, Claritin, and Benadryl. However, histamines do much more than just cause allergic reactions. Histamines regulate sleep, blood vessel dilation, and even heart rate. For this reason, heavily overdosing on these medicines can be fatal. This is also the reason that taking a normal dose of antihistamine can cause some sleepiness. Another solution to allergies are allergy shots. These are injections of small doses of allergens, which build up a tolerance to the allergy. In the long term, this decreases the body's response to the allergen and mostly eliminates the allergy. Hopefully, in a few decades, allergies will be a thing of the past.