Why do we have allergies??

It’s beginning to be that time of the year. You’re not sick, but your eyes itch, your nose runs and maybe a slight cough even develops. ALLERGY SEASON is here. I too, am susceptible to this annoying affliction, but why does our body respond so dramatically to something so seemingly harmless?

To understand allergies, one must first know a little bit about the immune system. The reason why we get sick or have similar symptoms to being sick is due to cells in our body called antibodies. Our immune system works by sorting through what particles are normal and which are foreign. If our body recognizes something as foreign, it will release antibodies that attach to that substance. Then other cells recognize the antibodies and initiate an immune response, often the release of histamine, that causes the outward symptoms we see when we are sick or have allergies.

Antibodies-attacking-a-virus1-1280x640
The green object is the foreign substance and the yellow and blue floating objects are the antibodies.

 

 

What happens when we have allergies is the immune system recognizes harmless substances like pollen, dust, certain foods and pet dander as foreign. This then causes an immune system response leading to the runny nose and other symptoms. A common treatment of these allergic symptoms is to take anti-histamines that help reduce the amount of histamine therefore lessening the severity of the symptoms.

But why does the immune system do that? Why doesn’t it see that these particles are harmless? An explanation called the “Hygiene Hypothesis” may offer some insight. It’s been observed that people in developed nations are developing allergies at an increasing rate whereas people in undeveloped countries are not. The reasoning for this may be that being exposed to parasites, bacteria and viruses at a young age helps the immune 2790228944_a30bdf2133_zsystem build up antibodies. These antibodies build up and essentially build resistance to them and once a person reaches older stages of life, they no longer have strong immune responses to these particles. People in developed countries have strong sanitation practices in place that don’t let children be exposed to as many substances. This may lead to them not developing as many antibodies as children in developing countries who are exposed to more of them. However, there is a trade off. Developing countries may have less allergies but due to a lack of advanced sanitation processes they are more likely to be affected by more severe diseases.

Although this Hygiene Hypothesis is plausible, it is only part of the story. The main cause of allergies is a hyperactive immune system. Some experts believe that this overactive antibodies are leftover immune responses from our ancient ancestors that helped save their lives. The molecules involved are quite similar to the ones that protect humans and other animals from venom and parasites. Perhaps when our species was more primitive, we were exposed to more genuinely harmful pollen-like substances, making allergic reactions a real lifesaver. These responses might have made us leave the area hence taking us out of harm’s reach.

Regardless of the cause, allergies still suck and there 040815_hepc_BODYseems to be no cure. Antihistamines, for now, are the primary way to keep the unpleasant symptoms at bay. Maybe it’s out of our hands because of genetics and maybe we should have rolled around in the dirt a little more as kids. The age old saying “rub some dirt in it” might now have some real application.

Sources:

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