How Cat Allergies Really Work And the Myths You Should Stop Believing

Jun 19, 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.

We love cats for their sass, their snuggles, and their never-ending judgmental stares. But for millions of people, cats come with an unfortunate sidekick: allergies.

If being near a cat sends you into a sneezy, itchy mess—or you know someone who insists they’re only allergic to long-haired breeds—it’s time for some real talk. Because most of what people think they know about cat allergies is… well, wrong.

Let’s dive into the science of what’s actually happening and clear up a few long-standing myths along the way.

cat allergies

First things first: it’s not the fur

Contrary to popular belief, fur is technically not the enemy. The true culprit is a microscopic protein called Fel d 1, found in a cat’s saliva, skin, and urine.

"Cat allergies are primarily caused by an allergen called Fel d 1. Fel d 1 is typically found in cats’ saliva, skin and urine. When cats groom themselves, their saliva sticks to their fur and becomes airborne when they shed." Dr. Andrew Findlaytor, MD, PhD, Doctor of Veterinary Medicine

So yes, longer hair might help spread the allergen, but even a hairless breed—like the Sphynx—can trigger symptoms. Why? Because it’s not the hair; it’s the protein.

Why Fel d 1 is so hard to escape

Fel d 1 is what scientists call a “sticky” allergen. It clings to furniture, clothing, and surfaces, and becomes airborne without much effort. Even more frustrating? According to the American College of Allergy, Asthma & Immunology, these allergens can persist for 20-30 weeks. That means if a cat lived in your home months ago, there could still be lingering allergens around.

What actually happens during an allergy attack?

The first time you’re exposed to Fel d 1, your immune system may not react. But over time, your body might become sensitized. This means you start producing IgE antibodies, which then attach to cells in your immune system—specifically mast cells and basophils.

Later exposures trigger a cascade:

Fel d 1 binds to your IgE antibodies
Those antibodies sound the alarm
Your immune cells release histamines
You end up with itchy eyes, hives, sneezing, and more

“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”
— Dr. David Zhang, PhD, a Harvard immunologist

Common myths about cat allergies (that we need to stop believing)

Myths are very common in the allergy space. Let’s break down a few:

Myth 1: "It’s the cat hair that causes allergies."
Truth: Not quite. Fur only carries the Fel d 1 protein—it’s not the source. Fel d 1 is found in cat saliva, skin, and urine. Hence, even a short-haired or hairless cat can trigger a reaction.

Myth 2: "Some cat breeds are completely hypoallergenic."
Truth: Although there are breeds that are less prone to cause allergies, remember every cat produces Fel d 1 allergens, hence, no breed is truly hypoallergenic. When selecting your next furry friend, research about the breeds that are less likely to cause allergies.

Myth 3: "If I rehome my cat, my allergy symptoms will disappear immediately."
Truth: Unfortunately, Fel d 1 hangs around . Due to its long half-life and stickiness, it can take months for allergy symptoms to subside, even after your cat is gone.

Myth 4: "Changing my cat’s diet will reduce allergens."
Truth: Diet alone doesn’t affect Fel d 1 production. However, new science-backed solutions like bioengineered protein toppers can neutralize allergens directly in your cat’s saliva.

Real solutions: fighting cat allergies the smart way

Good news—you don’t have to part ways with your cat. With a few smart strategies, you can reduce allergens at home and enjoy life with your feline companion.

Create cat-free zones: Keep bedrooms off-limits to give your immune system a break.

Groom wisely: Regular baths and brushing (ideally outdoors or by someone not allergic) can help reduce dander.

Use allergen-neutralizing sprays: Biotech products like Pacagen’s Cat Allergen Neutralizing Spray uses WhiskerBlock protein to target and bind to Fel d 1. It neutralizes the allergens in the air and on surfaces.

Try a food topper: Pacagen’s cat food topper uses WhiskerBlock proteins to neutralize allergens in your cat’s saliva—before they ever make it into the air.

Have an easy-to-wash cat/dog bed: Wash pet bedding weekly in hot water that is at least 130°F.

Final thoughts: you can absolutely coexist with your cat

Cat allergies are frustrating—but not unbeatable. By understanding the science, avoiding common misconceptions, and trying solutions grounded in actual research, you can breathe easier without giving up the companionship of your whiskered friend.

And remember: it’s not about blaming the cat—it’s about outsmarting the allergens.