What Causes Allergies In Adults?

Why am I getting allergies as I get older?

From food to environmental allergies, many adults find themselves experiencing allergic reactions for the first time, and it’s not uncommon to wonder why.

In fact, about 50% of adults with food allergies say at least one of their allergies manifested during adulthood [1]. So, what causes allergies in grown ups?

Well, as we age, our bodies change, which can affect how our immune system reacts to certain substances. This can result in developing adult-onset allergies or worsening of existing ones, causing significant discomfort and frustration. 

In this article, we’ll explore the underlying causes of allergies in adults and provide helpful tips for managing allergic reactions. So if you’re struggling with allergies, keep reading to learn more about this common but often misunderstood condition.

What are Adult-Onset Allergies?

To better understand adulthood allergies, we must first define an allergy.

Simply put, an allergy is a person’s reaction towards a specific substance upon contact that other people find harmless. These substances are known as allergens and can be found in food, insects, pets, pollen, or some medications. 

What happens is that your body’s immune system identifies these allergens as harmful, therefore releasing a messenger called immunoglobulin E to the cells requesting chemical defense against a foreign invader. 

Over time, and with repeated exposure to these allergens, your immune system develops an immunological memory. This makes the body respond faster after contact with certain substances. 

If the exposure to the allergens persists, your immune system can overreact, causing a mild allergic response like a runny nose. However, it can elevate to a severe allergic reaction like asthma symptoms if left unchecked. 

Allergies can manifest at any time in your life. Those that occur later in life, between your 20s and 80s, are called adult-onset allergies. 

4 Most Common Causes of Allergies in Adults

1 – Genetics

Your genetic makeup may predispose you to allergies or make you more susceptible to allergic reactions.

Studies show a 25% chance of getting certain allergies if one of your parents has them [4]. The risk rises to 60–80% if both parents have allergies. 

These allergies can manifest anytime, whether during childhood or adulthood. 

Research also links specific genes, such as those that affect the immune response, inflammation, and allergic sensitization, to allergies [5].

In addition, your body’s ability to metabolize some drugs or chemicals can also be affected by certain genetic variations. This raises the possibility of an allergic reaction. For instance, a genetic variation in some people can alter how their bodies process codeine, resulting in an allergic reaction.

It’s, therefore, essential to do a little digging into your family history for any cases of genetic-related allergies and consult your doctor for advice on preventing or managing them. 

Along with medical intervention, some probiotics, such as Quercetin and Bromelain, are recommended for natural allergy relief

To learn more about the uses and benefits of these supplements, you can refer to: Quercetin With Bromelain: X Uses And Benefits For Your Allergies.

2 – Environmental Factors

(Image source: Pixabay)

Exposure to some environmental elements, like dust mites, mold, animal dander, and pollen, can trigger allergic reactions in some people, especially those genetically predisposed to allergies [6]. 

These factors can make your immune system overreact, resulting in allergy symptoms like a runny or stuffy nose, sneezing, skin rashes, and itchy eyes. 

Numerous researchers concur that environmental factors play a significant role in the global rise in the prevalence of allergies [7]. The rising incidence of allergies has been linked to environmental factors such as climate change, pollution, and urbanization. 

For instance, longer pollen seasons and higher pollen counts have been linked to climate change, which can aggravate allergies in people predisposed to them.

Exposure to air pollution is also linked to aggravating symptoms of different allergies, including allergic rhinitis [8] [9]. Additionally, air pollution can increase the risk of allergies in offspring if the mother is exposed to it during pregnancy. 

Moving to urban areas after you’ve lived most of your life in rural areas could also increase your likelihood of getting adult-onset allergies [10]. This is because towns and cities have increased pollution levels, less exposure to beneficial microorganisms, and increased exposure to indoor allergens.

Note: Environmental factors can collaborate with other factors like genetics to influence the manifestation, development, and severity of sudden-onset allergies in adults. 

3 – Lifestyle Factors

Adult-onset allergies can develop and become more severe due to lifestyle factors like diet, exercise, and stress [11] [12].

These factors can interact with environmental and genetic factors to influence the immune system’s reaction to allergens.

Diet is one aspect of lifestyle that has been thoroughly researched in relation to allergies [13]. According to research, a diet high in fruits, vegetables, omega-3 fatty acids, and probiotics has been linked to a lower risk of allergies [14].

An increased risk of allergies has been linked to a diet high in sugar, saturated fats, and processed foods. This may be because these diets can lead to bodily inflammation, increasing the immune system’s sensitivity to allergens.

Another lifestyle factor that may affect the development of allergies in adults is exercise. Although regular exercise has many positive health effects, some studies suggest that intense exercise may increase the risk of allergy development [15]. 

This could result from the body’s tendency to release histamines during exercise, which can result in severe allergic reactions in susceptible people [16]. 

Quercetin is a natural allergy relief support supplement for healthy histamine production and maintenance. 

Stress has also been linked to the onset and severity of allergies [17]. High-stress levels trigger increased cytokine production, an inflammatory molecule exacerbating allergic reactions.

Stress can also weaken the immune system, making it more vulnerable to allergies and infections.

4 – Work/Occupation

Occupational exposure to allergens like chemicals, dust, mold, and latex is a well-known cause of adult-onset allergies [18]. In fact, about 25% of cases of adults with asthma can be traced back to occupational factors. 

Common industries linked to occupational allergies include food processing, animal handling, mining, agriculture, and healthcare. 

Farm workers are exposed to pesticides, pollen, and molds. For healthcare workers, it’s latex, medications, and cleaning chemicals. Animal handlers contact animal waste and dander, while food processing workers shellfish and nuts. All these substances can cause allergic reactions. 

Typically, occupational allergies develop over time and occur suddenly. The common symptoms include a runny nose, skin rashes, and itchy eyes. Some people may experience severe allergic symptoms like asthma, among other respiratory illnesses. 

Therefore, you should be very sensitive about your working environment and always wear protective materials like masks and other safety outfits to prevent exposure to possible allergens. 

What Are the 7 Common Types of Allergies Affecting Adults?

(Image source: Pexels)

Most allergies are either seasonal or life-long. The table below explains some of the most common allergies in adulthood. 

Type of AllergyAllergenDescription
Seasonal AllergiesPollenWeeds, grasses, and tree pollen bring on these allergies. Some possible symptoms are sneezing, running nose, itchy eyes, and congestion.
Pollen allergy is also known as hay fever. 
Food AllergiesMilk (dairy products)
Tree Nuts
Food allergies are a global issue. A recent study indicates that up to 10.8% of the world’s population suffers from various food allergies [2].
These allergies can be IgE-mediated, non-IgE-mediated, or intolerances [3].
These allergies can also cause various symptoms, from mild itching or hives to severe anaphylaxis, which can be life-threatening.
Insect StingsHornet
These allergies occur when your body overreacts to insects’ venom. Symptoms may include difficulty breathing, swelling, redness, and itching at the point of contact.
Severe occurrences can result in anaphylaxis.
Allergic RhinitisMold
Pet dander
Dust mites
The most common allergic response to this allergy is inflammation in the nasal passages.  
Drug AllergiesChemotherapy drugs
Medication allergies occur when your immune system reacts to certain drugs. Symptoms range from mild rashes to a life threatening reaction called anaphylaxis. 
Latex AllergiesNatural rubber latexIf your body reacts to natural rubber latex products like balloons, condoms, and gloves, you may experience symptoms like itching, hives, or anaphylaxis. 
Contact DermatitisNickel
Poison ivy
This is an itchy rash that results from contact with specific allergens. The allergy is characterized by irritable and uncomfortable skin with rashes. The allergy usually manifests within a few days of exposure. 

This video can also add to your knowledge on allergies:

Let’s review some of the most common causes of allergies during your adulthood. 

Diagnosis and Treatment of Allergies in Adults


If you suspect you have an adult-onset allergy, avoid self-diagnosis and over-the-counter meds and visit your nearest physician for a proper diagnosis. Physicians usually diagnose allergies using a combination of your medical history, physical exam, and allergy tests. 

Adults with allergies can frequently be diagnosed using the following techniques:

Method of DiagnosisDescription
Blood TestsThe physician will measure IgE antibody levels to specific allergens in your blood. 
Skin TestsThe physician applies small amounts of an allergen and then does a skin prick to allow it to enter the body. You’re allergic to the substance if a lump or redness forms on the test area. 
Elimination DietIt involves removing certain foods from your diet to determine if they are causing an allergic reaction.
Medical HistoryYou’ll be interrogated about your family’s medical history, especially if anyone in your family had allergic reactions to certain substances. 

If you’re wondering whether you have an allergy or not, here are the common signs and symptoms that indicate an allergy:

  • Sneezing, runny or stuffy nose, or watery eyes.
  • Skin rash or hives.
  • Wheezing or trouble breathing.
  • Abdominal pain, diarrhea, or vomiting after eating certain foods.

Treatment of Common Adult-Onset Allergies

The treatment for sudden-onset allergies in adults entails managing the current symptoms and curbing future allergic reactions. The most common treatments include:

  • Allergy Medications: Using drugs such as nasal corticosteroids, decongestants, and antihistamines can help alleviate allergy symptoms.
  • Immunotherapy or Allergy Shots: Injection of tiny amounts of allergens into the body to gradually desensitize the immune system and lessen allergic reactions.
  • Changes in Lifestyle: Avoiding allergens, managing stress, using air filters, and keeping your home and working space clean can help reduce exposure to allergens and alleviate common symptoms.
  • Use Probiotics: Some studies suggest that these live microorganisms may help alleviate allergy symptoms by modulating the immune system and decreasing inflammation [19]. One such probiotic is MegaSporeBiotic. It’s known for supporting a healthy gut mucosa — which can help prevent allergic diseases from developing [20].

To learn more about D-Hist and its health benefits, read: Natural D Hist: Uses, Benefits, And Correct Dosage 

Note: Probiotics are not a replacement for other allergy treatments and should be used with other therapies as prescribed by a doctor.

Take Control of Your Adult Allergies!

Adult allergies are brought on by a complex interplay of immune system dysregulation, environmental triggers, and genetic predisposition. 

Adults with allergies should identify their unique triggers and work with their healthcare provider to create a personalized treatment plan. This plan may include allergen avoidance, medication, immunotherapy, or a combination of these methods. 

If you suffer from allergies, you may find it easier to control the symptoms and live better overall if you’re aware of the underlying causes of your condition.

Further reading – Fall Is Coming: 5 Natural Remedies For Allergies



[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7899184/

[2] https://www.immunology.theclinics.com/article/S0889-8561(21)00009-6/fulltext

[3] https://www.ncbi.nlm.nih.gov/books/NBK482187/

[4] https://www.healthychildren.org/English/health-issues/conditions/allergies-asthma/Pages/Allergies.aspx

[5] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4610744/

[6] https://www.aaem.pl/Environmental-factors-and-allergic-diseases,71806,0,2.html

[7] https://pubmed.ncbi.nlm.nih.gov/23020042/

[8] https://www.worldallergy.org/UserFiles/file/WhiteBook2-2013-v8.pdf

[9] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3192198/

[10] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8284864/

[11] https://www.nature.com/articles/479S2a

[12] https://www.ifm.org/news-insights/environmental-lifestyle-determinants-of-allergic-diseases/

[13] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7522364/

[14] https://www.everydayhealth.com/allergy-pictures/foods-that-fight-allergies.aspx

[15] https://www.anaphylaxis.org.uk/exercise-induced-or-worsened-anaphylaxis-knowing-the-difference/

[16] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5161583/

[17] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3264048/

[18] https://patients.eaaci.org/occupationalallergy/

[19] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8064452/

[20] https://www.frontiersin.org/articles/10.3389/fcimb.2021.650893/full

Follow me

Medically reviewed by Dr. Jamy Antoine, D.C. — by Chris Bowman — On August 31, 2023


Chris Bowman

Chris Bowman is the CEO and Co-Founder of SimplyNutrients.com and has over 15 years of experience in nutritional sciences and wellness. Simply Nutrients is a part of Dr. Jamy Antoine's Select Health Practice in Edina, Minnesota. Chris is passionate about helping people live healthier lives by using the best practices of nature, nutrition, and medicine.