Why in all HECK do I have allergies?!?!?!

BY ZACHARY ABBOTT

What is an allergy? I’m sure we’re all familiar with an allergy in concept— something that you can’t come in contact with— but how do allergies actually work? How do we get them? Are they genetic? Are they acquired? Let's get to the bottom of this. 

An allergic reaction is caused by your immune system detecting something harmless and deciding that it’s something dangerous. So, it responds— responds with terrible ends. You could get a fever, a rash, or even have your throat close up so that you can’t breathe. You can have allergic reactions to almost anything. Some common allergens include milk, nuts, and eggs. Some rare allergens include red meat, water, and sunlight. 

So what’s the deal? Why do we have allergies? The most prevalent theory is that allergies are a misfire of a system designed to deal with parasitic worms, but perhaps this question is flawed. It doesn’t matter why we have allergies, we have them, so how did we get them? Are they genetic? Or acquired?

Like everything in biology, it’s complicated. There are genetic allergies and acquired allergies, but this isn’t as binary as people would believe. Yes, allergies run in families, if your mother has a peanut allergy, you’re more likely to have one, but “more likely” is the key word here. Atopy is a genetic predisposition to developing an allergic disease. Hear that? Developing. 

While your family might be predisposed to develop certain allergies, you could completely avoid it. This is because the development of an allergy requires your body to make antibodies against the allergen. This in itself requires the allergen to reach a B cell for the B cell to differentiate into a form that can produce the antibodies. So, avoiding certain allergens can make it so you won’t become allergic to something. 

Blood worm by Mary L.

This can also work in reverse. Blood worms are a common aquarium food that most people aren’t allergic to. But, through constant contact with blood worms, many fish breeders will eventually become allergic to them as their body hits that rare chance and a B cell starts producing antibodies. 

But let's go back to the genetic angle, what part of your genes determine your allergies? Like everything in the body, it comes down to your SNPs. Based on the SNPs you have, you may or may not be predisposed to an allergy. Then, based on your exposure, you may or may not develop the actual allergy. If you do, your body will start developing antibodies to deal with that “ever so deadly” allergen. 

So. Genetic or Acquired? Probably best to leave it with a “It’s complicated.”

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InformedHealth.org [Internet]. Cologne, Germany: Institute for Quality and Efficiency in Health Care (IQWiG); 2006-. Overview: Allergies. [Updated 2023 Aug 8]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK447112/

Brown P, Nair B, Mahajan SD, Sykes DE, Rich G, Reynolds JL, Aalinkeel R, Wheeler J, Schwartz SA. Single nucleotide polymorphisms (SNPs) in key cytokines may modulate food allergy phenotypes. Eur Food Res Technol. 2012 Nov;235(5):971-980. doi: 10.1007/s00217-012-1827-3. PMID: 23230389; PMCID: PMC3516859.

Ortiz RA, Barnes KC. Genetics of allergic diseases. Immunol Allergy Clin North Am. 2015 Feb;35(1):19-44. doi: 10.1016/j.iac.2014.09.014. Epub 2014 Nov 21. PMID: 25459575; PMCID: PMC4415518.