Cat Allergies vs Dog Allergies. Why Do Cats Trigger More Allergic Reactions?


Allergies to pets are very common, especially allergies to cats and dogs. However, research shows that people are much more likely to be allergic to cats than dogs. A major reason for this is that cats produce and spread more of the Fel d 1 protein that causes most cat allergies than dogs spread of Can f 1, the protein behind most dog allergies. Cats also groom themselves extensively, spreading allergens through the air and depositing them all over the home. In comparison, dogs generally release less allergen and spread it less readily than cats. However, some hypoallergenic dog breeds produce minimal allergens and are suitable for most people with pet allergies. Understanding the differences between cat and dog allergens and allergy symptoms can help those considering a pet choose the right animal for their home and manage any allergies that do occur.

Cats Produce More Allergen

The main allergen in cats that causes reactions in humans is a protein called Fel d 1. Cats produce much higher levels of Fel d 1 compared to dogs producing Can f 1 1. While all cats produce Fel d 1, some cats produce up to 3 times more of the allergen than others. Fel d 1 is found in cats’ skin as well as in their saliva, anal glands, and sebaceous glands. Cats spread Fel d 1 throughout their coat when they lick and groom themselves. The levels of Fel d 1 differ based on the cat’s sex and if they have been neutered/spayed. Non-neutered male cats produce more Fel d 1 than neutered males or female cats. So cats tend to have much higher levels of allergen compared to dogs.

Allergen Is Lighter and Airborne

One key reason why felines trigger more allergies than canines is because the prominent cat allergen Fel d 1 is much smaller and lighter than the primary dog allergen Can f 1. Fel d 1 particles have a molecular weight around 34 kDa, whereas Can f 1 particles are around 70 kDa, or more than twice as large.

This difference in size means Fel d 1 allergens can remain airborne for many hours in indoor environments. They easily spread throughout rooms and entire buildings via air currents. In comparison, the larger Can f 1 particles tend to settle on surfaces within 20-30 minutes after being shed. A 2008 study found airborne Fel d 1 concentrations up to 5 times higher than Can f 1 in homes with both cats and dogs present.

The longer time Fel d 1 spends floating in the air increases the chances of people breathing in the particles and triggering allergic reactions. Even in rooms cats are not allowed in, air currents can transmit cat allergens from other areas of a home or building.

Cats Groom Themselves More

One of the main reasons why cats produce more allergens than dogs is because they groom themselves much more frequently. Cats spend up to 30% of their waking hours licking and grooming themselves with their rough tongues.[1] This spreads allergenic proteins like Fel d 1 from their saliva across their fur. These allergens then get released into the air or transferred to surfaces when a cat settles down. Dogs, on the other hand, mostly shed allergens passively through flakes of dander and dead skin cells. They do lick themselves as well, but not nearly to the same obsessive degree as cats.

In addition, the repetitive self-grooming and stimulation of the skin by cat tongues causes their skin to produce more dander than a dog’s skin. The barbs on a cat’s tongue act like a comb that can loosen and release dander into the environment. So cats end up distributing allergens both from their saliva as well as their skin when they groom.

Cat Allergen Is Sticky

One important difference between cat and dog allergens is that the major cat allergen, called Fel d 1, is very “sticky.” This means the particles easily attach themselves to surfaces, fabrics, skin, and hair. As a result, cat allergen can be found lingering in a home long after a cat is gone. According to research, “Cat allergen, most importantly Fel d 1, is buoyant and “sticky,” which means it easily remains airborne and may last in a home for up to 6 months after a cat is removed” [1].

In contrast, the major dog allergen Can f 1 is less sticky. This means it is less likely to attach to surfaces and fabrics compared to cat allergen. Dog allergen also becomes airborne less easily. As a result, dog allergen does not persist in a home as long as cat allergen does after the dog has left.

Some Dog Breeds Are Hypoallergenic

While no dog is completely non-allergenic, some breeds produce fewer allergens than others and may be better tolerated by people allergic to cats. The allergens people react to are found in pet dander and saliva. Dogs that shed less tend to release less of these allergens into the environment. According to AKC, popular hypoallergenic dog breeds include:

Poodles – Poodles have a coat of hair rather than fur so they tend to shed less. Their tight curly coat also traps dander and allergens close to their body rather than releasing it into the air.

Maltese – The Maltese has a long, silky coat of hair that sheds minimally. Daily brushing can further reduce loose hairs and dander.

Bichon Frise – This petite, fluffy breed has a hypoallergenic coat that requires frequent grooming to prevent tangles and shedding.

While some hypoallergenic breeds may be better tolerated than cats by people with allergies, consult with your doctor before bringing any new pet home. Some people may still react to “hypoallergenic” dogs. However, breeds that shed less tend to release fewer allergens, potentially making them more suitable than cats for people with allergies.

Reducing Cat Allergen Levels

There are several ways to reduce the levels of the Fel d 1 allergen in your home to help manage cat allergies:

Frequently bathe your cat using cat shampoos designed to reduce dander. Shampooing once a week can significantly reduce allergen levels. Be sure to use products formulated for cats and follow directions carefully [1].

Use high efficiency HEPA air filters to remove allergens from the air. HEPA filters are designed to capture very small particles like cat dander that regular filters let through. Place air filters in rooms where you spend the most time with your cat [2].

Vacuum frequently using a vacuum with a HEPA filter, concentrating on surfaces where dander accumulates like upholstered furniture, rugs, and cat beds. Wear a face mask while vacuuming to avoid inhaling stirred up allergens [1].

Wipe down surfaces frequently with a damp cloth or allergen reducing wipes to remove dander. Pay special attention to soft furnishings and fabrics which can harbor allergens [3].

Managing Cat Allergy Symptoms

There are several ways people with cat allergies can manage their symptoms and minimize reactions. Some common options include:

Antihistamines: Over-the-counter oral antihistamines like cetirizine (Zyrtec), fexofenadine (Allegra), and loratadine (Claritin) can help relieve sneezing, itchy and watery eyes, runny nose, and other allergy symptoms. These are available in pill or liquid form. Newer prescription antihistamines like desloratadine (Clarinex) may be more effective.

Nasal sprays: Corticosteroid nasal sprays like fluticasone (Flonase) and triamcinolone (Nasacort) can reduce inflammation in the nasal passages and relieve congestion. These need to be used regularly to be effective.

Allergy shots: Allergy shots or immunotherapy involves getting injections of small amounts of cat allergen extract over time. This helps the body build tolerance and results in long-term allergy relief. Treatments are given 1-2 times per week for up to 6 months initially.

Avoid direct contact: Keeping exposure to cats minimal can help reduce allergy symptoms. Washing hands after touching cats, using HEPA air filters, and keeping cats out of bedrooms can all help.

People with severe cat allergies may need to use a combination of oral and nasal medications plus environmental controls for the best relief. Consulting an allergist can help determine the most effective treatment options.

Getting a Non-Allergenic Cat

While no cat is completely non-allergenic, some breeds produce less of the Fel d 1 protein that triggers allergic reactions in humans. Certain cat breeds like the Siberian, Oriental Shorthair, and Cornish Rex are known to be less likely to cause allergies.

The Siberian is a large, long-haired breed that originated in Russia. They produce lower levels of Fel d 1 compared to other cats, so they tend to not cause as many allergic reactions. According to, Siberians only trigger allergies in about 10-15% of people, compared to up to 50% for other cat breeds.

Oriental Shorthairs have a Siamese body type but with short, sleek fur. They also produce less Fel d 1 protein. The Cornish Rex has very fine, curly hair and sheds minimally, so the allergen doesn’t get dispersed as much into the air. While not completely hypoallergenic, these breeds cause fewer allergy issues for most people.

It’s still possible to be allergic even to less allergenic cat breeds, so it’s recommended that people sensitive to cats spend time around the specific cat they are considering getting to see if they have a reaction. But those set on having a cat despite cat allergies may fare better with one of these breeds that tend to be less allergenic.


In summary, cats tend to cause more allergy issues than dogs for several key reasons:

Cats produce a protein called Fel d 1 that is very lightweight and spreads through the air easily, while dogs produce fewer airborne allergens. Cats also groom themselves more often, spreading saliva and dander that contains Fel d 1 all over their fur. This makes cat allergens very “sticky” and likely to cause reactions. Dogs typically don’t spread allergens as much when grooming.

Additionally, some dog breeds like Poodles and Schnauzers are considered hypoallergenic because they produce fewer allergens. There are no hypoallergenic cat breeds. While some steps can be taken to reduce cat allergens, like bathing and wiping paws, the proteins cats produce will always affect those with allergies.

In the end, cat allergens are simply more abundant and airborne compared to dogs. Those with pet allergies usually have an easier time with dogs, especially specific hypoallergenic breeds. While not impossible, managing cat allergies takes more effort and care.[1]

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