Why Do Allergies Exist?

| Fremont, California

Common allergens surrounding someone who is sneezing

In the spring, flowers bloom, and temperatures increase. For many people, spring also means keeping a constant supply of tissues, sneezing frequently, and avoiding rubbing their itchy eyes.  Then there are people who need to totally abstain from certain foods such as peanuts and seafood as even a small amount can trigger a strong allergic reaction. But despite how common allergies are, we never really give a second thought to them even though they are quite an unusual phenomenon. So what is really behind allergies? 

Immunity plays an important part in developing allergies. Your immunity is meant to keep your body safe from all kinds of potentially harmful bacteria, viruses, and parasites by producing a substance called Immunoglobulin E (IgE). But sometimes the body gets confused and identifies harmless substances like pollen or pet dander as a potential danger.

When exposed to the same allergen again, your body produces the Immunoglobulin E antibody and the immune system releases chemicals such as histamine, the very cause of all allergy symptoms: sneezing, runny nose, itching, and redness. To conclude, people do not suffer from allergies because of pollen and dust but because of their own body's reaction.

Which then makes us wonder: Why has our immune system evolved to behave like this at all?

The thing is, science doesn’t really have one definitive answer to this question yet. The most popular hypothesis is the hygiene hypothesis, which posits that because modern people are exposed to cleaner environments compared to our predecessors, our immune system receives less exposure to microorganisms when we are young. Thanks to the use of antibacterial soap, antibiotics, clean water, and spending a lot more time inside rather than outside, we’re living in an environment different from the one our forefathers had.

And although it’s been crucial for improving public health in the world, some experts suggest that there’s a side effect to all of this – our immune system, lacking real threats to fight against, might become oversensitive to certain triggers and react to things that don’t necessarily require any reaction. The hygiene hypothesis is not considered a full explanation of how allergies work, but it does help explain their growing prevalence in recent decades.

Of course, the environment is not the only determining factor here. Genetics also plays a role. In case one or both of your parents have allergies, the likelihood is high that you will experience the same problems. However, genes alone do not fully account for allergic reactions. Two siblings can be raised in the same family but may have entirely different allergies. All sorts of factors, ranging from environmental pollution and diet to infections in childhood and microbial exposure, can affect the development of the immune system.

If you have ever asked yourself why the symptoms of seasonal allergy get particularly strong in springtime, the answer lies right on the surface. Trees, grasses, and weeds release pollen into the air in order to reproduce. For an average person, pollen does not represent a threat, yet for a patient who suffers from seasonal allergies, every grain becomes a potential cause of an attack.

Allergies do not kill; however, in rare instances, they can be deadly. Severe allergic reactions called anaphylaxis cause swelling in the throat, breathing problems, and a fast fall in blood pressure. Certain foods like peanuts, tree nuts, shellfish, some medications, and insect stings are more likely to cause these kinds of reactions. Due to the speed of these reactions, people usually carry an epinephrine auto injector that helps to temporarily stop the reaction while waiting for medical help.

However, people should not be pessimistic about their allergies as they can disappear sometimes. For instance, some children can grow out of their allergies to milk or eggs while others retain the allergy through their whole lives. Seasonal allergies can also change severity and frequency, depending on many factors including age. Scientists are yet to figure out why allergies change.

Despite the lack of a cure, people have a variety of options when it comes to managing their allergies. They can use antihistamines and nasal sprays to cope with their symptoms. Another way of managing allergies is allergy immunotherapy, also known as allergy shots.

It is surprising how a harmless particle like pollen can leave a person in agony for weeks. However, the occurrence of allergic reactions is not an indication of a weak immune system; rather, it is a confused effort to protect the organism from harm.

After many years of investigations, scientists are still discovering new things about allergic reactions and their causes. Any knowledge received about them is useful not only for understanding the nature of allergic reactions, but also for learning more about the functioning of the immune system. Thus, when a person sneezes because of flowers or has to carefully read an ingredient list, it means his or her body is not making a mistake. It’s simply trying to protect them from a threat that doesn’t actually exist.

Works Cited

“Allergens and Pollen | Climate and Health.” CDC, https://www.cdc.gov/climate-health/php/effects/allergens-and-pollen.html. 

“Allergens | National Institute of Environmental Health Sciences.” National Institute of Environmental Health Sciences, https://www.niehs.nih.gov/health/topics/agents/allergens. 

“Allergies and the Immune System.” Johns Hopkins Medicine, https://www.hopkinsmedicine.org/health/conditions-and-diseases/allergies-and-the-immune-system. 

“Allergies - Symptoms and causes.” Mayo Clinic, 24 August 2024, https://www.mayoclinic.org/diseases-conditions/allergies/symptoms-causes/syc-20351497. 

“Allergy shots.” Mayo Clinic, 13 April 2024, https://www.mayoclinic.org/tests-procedures/allergy-shots/about/pac-20392876. 

“Asthma: The Hygiene Hypothesis.” FDA, https://www.fda.gov/vaccines-blood-biologics/consumers-biologics/asthma-hygiene-hypothesis. 

“What Is Histamine?” Cleveland Clinic, https://my.clevelandclinic.org/health/articles/24854-histamine.