so back out in any way that it

so what exactly are allergies? an allergy is when our immune system responds to something that is usually harmless – things like pollen, cat hair, and peanut butter – and treats it like something dangerous. so when our bodies come into contact with one of these substances, called an allergen, our immune system goes into overdrive trying to get the allergen out of the body. this results in your typical allergic reaction – coughing, sneezing, and watery eyes are a few of the symptoms. but what is actually happening inside our bodies that causes that reaction? let’s break it down using pollen as an example. every year around march, trees start mass producing pollen. tree pollen is airborne, meaning that is uses the wind to go from tree to tree, making it really easy for us to breathe in. once we breathe in the pollen, our immune system immediately starts trying to get the pollen back out in any way that it can. the first step in the immune response is for an antibody called immunoglobulin e or ice to attach itself to the pollen. this sends a signal to the body to release histamine. histamine is a hormone that is made by specialized white cells called mast cells. must cells are found everywhere you experience a typical allergic reaction, like your eyes and your nose. when the histamine is released, it does two things, one it causes the blood vessels nearby to expand and allow increased blood flow to the area, so that white blood cells can access the area to fight off a potential infection. two, histamine stimulates the release of fluids from the blood vessels, which results in allergy symptoms like watery eyes. this is the body’s way of trying to flush out the allergen, in this case the pollen, which explains why in spring everyone is always coughing and sneezing. but why do we have allergies at all? it makes no sense for our immune system to have such a dramatic response to something harmless like pollen. the truth is, we don’t really know why we have allergies. but one possible explanation is the hygiene hypothesis. the hygiene hypothesis is a working theory about why, in recent decades, we have seen a dramatic increase in allergies in certain parts of the world. it says that people living in heavily industrialized nations like the united states have the highest allergy rates because we are not exposed to the same harmful bacteria and viruses that people living in developing nations are. because of this, our immune systems do not develop in the same way, and without that exposure our systems began to go after other things instead, things like peanut butter

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