Types of Environmental Allergies and How They Affect You

Jun 28, 2025

Written by: Pacagen Team
Reviewed by: Evan Zhao, PhD
Evan is a bioengineer, a loving dad to Miao Miao, and the founder and CEO of Pacagen.

If your eyes water just thinking about spring or your skin starts to itch when a dog walks by, you're not alone. Millions of people deal with environmental allergies, often without realizing just how many forms they can take—or how deeply they can impact everyday life.

Let’s walk through the most common types, what triggers them, and why some allergens seem to follow you no matter how clean your home is.

environmental allergies

What are environmental allergies, really?

Environmental allergies are immune responses to everyday substances like pollen, pet dander, or dust mites. While these particles are usually harmless, for those with sensitive immune systems, they can spark a chain reaction of inflammation, congestion, sneezing, rashes, and even brain fog.

As Harvard physician-scientist Dr. Ben Ouyang, MD, PhD, explains:

“Allergy symptoms vary from mild to severe and common to uncommon. Depending on the type of allergy, these might be seasonal (e.g., pollen) or perennial (e.g., pet or dust).”

So what’s behind these reactions? According to Harvard immunologist Dr. David Zhang, PhD:

“At a high level, allergic responses are driven by about half a dozen key contributors in your immune system, which work together in complex, but very cool ways to give rise to a vast range of symptoms.”

Let’s get to know some of the most common culprits.

1. Cat allergies

One of the most common offenders in American households is the humble housecat. But the problem isn't fur—it’s a tiny protein called Fel d 1, found in a cat’s saliva, skin, and urine. As cats groom themselves, this allergen sticks to their fur and becomes airborne.

Veterinarian Dr. Andrew Findlaytor, DVM, notes:

Because of this, there are three main factors that make a cat more prone to cause allergies: fur length, grooming and shedding frequency, and Fel d 1 production.

Even homes without cats often have lingering Fel d 1. Its half-life is so long that traces can remain for up to 20–30 weeks. Worse, the amount of Fel d 1 someone breathes in with a cat around can be equal a year’s worth of dust or pollen exposure.

2. Dog allergies

Dog allergies are caused by multiple proteins, primarily Can f 1 and Can f 2, which are found in saliva, dander, skin oils, and urine. And just like with cats, fur length and grooming habits can affect how much allergen circulates in the air.

As Dr. Findlaytor points out:

“It is not uncommon for allergic people to experience a broad spectrum of symptoms. If dander is inhaled, you might get cold-like symptoms, whereas if you come into contact with a dog’s saliva or oil secretions, you might get skin rashes.”

Dog allergens are hard to manage. Nevertheless, it has been proven by scientific studies that cat allergies are still more prevalent and more likely to cause symptoms, even though there are more dog owners than cat owners.

3. Dust mite allergies

Dust mites themselves don’t bite or sting, but their droppings are packed with allergens—especially the most common allergen called Der p 1. This protein is especially sneaky: it breaks down your respiratory lining and interferes with your immune response.

Der p 1 acts like tiny scissors, slicing through your body’s protective barriers and making it easier for allergens to trigger your immune system. It’s been linked not just to allergies but to a higher risk of developing asthma, too.

Warm, humid environments are dust mites’ favorite. Bedding, carpets, and upholstered furniture are often their playgrounds.

4. Pollen allergies

Often dubbed “hay fever,” pollen allergies are technically caused by microscopic grains from trees, grasses, and weeds. One of the most common pollen allergens is Bet v 1, produced by birch trees.

Pollen is everywhere during its season—and it’s a lot sneakier than you think. It sticks to your clothes, skin, and even your pets’ fur, hitching a ride straight into your home.

Depending on where you live:

Trees usually pollinate between February and April
Grasses peak from April to early June
Weeds dominatefrom August until the first hard frost

In warmer regions? Pollen might be in the air year-round.

Allergy symptoms aren’t always what you expect

Sure, sneezing and itchy eyes are common signs. But many people experience less obvious symptoms:

Skin reactions like eczema, hives, or red patches
Gastrointestinal issues such as nausea or cramps (yes, even from airborne allergens)
Brain fog, fatigue, and migraines due to sleep disruption from nasal congestion
Facial puffiness or sinus-like facial pain
In rare cases, even anaphylaxis can occur

So, what can you do?

Managing environmental allergies isn’t about finding one magic solution—it’s about layering smart choices. The good news? There are several proven strategies to help reduce exposure and ease your symptoms:

Modify your habits:

Simple changes like vacuuming with a HEPA filter, washing bedding in hot water weekly, and using damp cloths to dust can drastically reduce allergens in your home. Regular cleaning keeps dander, pollen, and dust mites from building up and becoming airborne.

Change your environment:

Swapping out carpets for hard flooring, using allergen-proof bedding covers, and running air purifiers with HEPA filters can go a long way. Keeping windows shut during pollen season and managing indoor humidity (ideally around 40-50%) also helps curb allergens like dust mites.

Use medication when needed:

Over-the-counter antihistamines and nasal corticosteroids provide quick relief for many. For long-term relief, allergy immunotherapy (like allergy shots or sublingual tablets) can help your body build tolerance—but this route requires time, consistency, and sometimes years of treatment.

Explore emerging solutions:

Biotech-driven approaches are making it easier to manage allergies without relying solely on medication. Products like allergen-neutralizing sprays or pet food toppers—developed by scientists at Pacagen—target allergens directly in the air, on surfaces, or even at the source (like pet saliva). These are designed to work alongside your existing routine and offer an additional layer of protection.

As Dr. Evan Zhao puts it:

"The allergen neutralizing formula harnesses the power of naturally engineered proteins to precisely target and neutralize specific allergens, including cat, dog, and dust mite allergens…"

This means fewer meds, fewer side effects, and a more direct approach to fighting allergens—whether they’re floating in the air or hiding in your couch.

The best plan is one that works for you. Often, it’s a combination of small actions that add up to major relief.

Final Thoughts

Environmental allergies aren’t just seasonal annoyances—they can affect your sleep, focus, and overall well-being. But the more you know, the better you can protect yourself. Whether your trigger is the neighbor’s cat, your own dog, or the changing seasons, you don’t have to suffer in silence.

With a little education, some smart habits, and the latest biotech tools, managing allergies is no longer just about coping—it’s about thriving.