Get Healthy!

• Posted June 25, 2025

What Does Science Say About Pet Allergies?

If spending time around dogs or cats makes your eyes water, your nose run, your skin itch or your breathing difficult, you’re not alone.

Pet allergies — allergic reactions to proteins found in an animal's skin cells, saliva or urine — affect 10% to 20% of people worldwide, and exposure isn’t limited to pet owners.

Scientists at the National Institute of Environmental Health Sciences (NIEHS) have found that dog and cat allergens are present in nearly all U.S. homes, even those without pets.

The American College of Allergy, Asthma, and Immunology (ACAAI) recommends that anyone experiencing persistent allergy symptoms see a board-certified allergist. Testing can determine whether pet allergens are the cause, and an allergist can develop a personalized treatment plan to help you manage symptoms effectively.

Understanding the science behind pet allergies can help you take control of your symptoms, reduce your exposure and explore treatment options that provide long-term relief.

Pet allergens are nearly impossible to avoid

Many people assume pet allergies are caused by a dog’s or cat’s fur, but the real culprits are tiny allergen particles found in an animal’s dander (dead skin flakes), saliva and urine.

These microscopic proteins easily become airborne, settling on furniture, clothing and carpets. They can even be carried on people’s clothes, spreading to schools, workplaces and public spaces — even homes without pets.

Research shows that allergens can linger in a home for up to 30 weeks after a pet has been removed, making exposure difficult to avoid. Even thorough cleaning may not eliminate them completely.

Growing up with pets may lower allergy risk

Research suggests that early exposure to pets may help reduce the risk of developing allergies and asthma. Some studies have found that infants who were exposed to pets and certain bacteria before their first birthday were less likely to develop allergic conditions later in life.

This supports the idea that early-life exposure helps train the immune system to tolerate allergens rather than overreacting to them.

However, for older children and adults who already have pet allergies, continued exposure does not appear to have the same protective effect. In fact, in some cases, ongoing exposure may worsen symptoms over time, particularly for those with asthma.

Scientists are just beginning to explore whether preconception exposure — a parent's exposure to pets before having children — might also play a role in allergy development.

Pet allergy symptoms can be mistaken for colds or seasonal allergies  

Pet allergies often cause symptoms that mimic seasonal allergies or even the common cold, making them easy to overlook. If you notice that symptoms appear after spending time around pets, it may be a sign of a pet allergy.

Common symptoms include:

• Sneezing, runny nose or nasal congestion

• Red, itchy, or watery eyes

• Coughing, wheezing or shortness of breath

• Skin reactions such as hives or eczema

• Worsening asthma symptoms

If these symptoms persist or become more severe, seeing a board-certified allergist can help confirm whether pet allergens are the cause and provide guidance on managing your symptoms.

Allergists use skin and blood tests to diagnose pet allergies

An allergist can use skin or blood tests to determine if you have pet allergies.  The type of test used will depend on your medical history and specific symptoms.

Common allergy tests include:

• Skin prick or scratch test: A small amount of a suspected allergen is placed on the skin of your forearm or back, then lightly pricked or scratched. If you are allergic, a small, red, itchy bump (like a mosquito bite) will appear within 15 minutes. To ensure accurate results, you may need to stop taking antihistamines for 3 to 7 days before the test. Your allergist will provide specific instructions.

• Blood test (IgE test): This test checks for specific antibodies (IgE) in your blood to detect an allergic reaction. While it can confirm an allergy, it does not measure how severe the reaction might be.

With a clear diagnosis, an allergist can develop a personalized treatment plan to help reduce symptoms and improve quality of life.

Can you keep a pet if you’re allergic?

While removing the pet from the home is the most effective way to reduce exposure, many people prefer to focus on minimizing allergies while keeping their beloved pets. Research-based strategies can help pet owners manage their allergies and reduce symptoms.

Ways to reduce pet allergens at home:

• Keep pets out of the bedroom.

• Use HEPA air filters.

• Wash hands after petting animals.

• Bathe your pet regularly.

• Use a vacuum with a double or micro-filter bag.

Immunotherapy is the only long-term treatment option

Over-the-counter and prescription allergy medications can provide relief, but immunotherapy (allergy shots) is the only long-term treatment option. Studies show 60% to 80% of patients receiving immunotherapy for dog or cat allergens experience significant symptom relief over time.

Immunotherapy works by gradually desensitizing your immune system to pet allergens, but it does require commitment — it may take up to a year to see improvement, and treatment can last five years or longer.

Many people find that a combination of allergen-reducing measures at home, medication and immunotherapy allows them to live more comfortably with their pets.

Hypoallergenic pets are a myth

Many people believe that certain breeds — like poodles, Portuguese water dogs or Siberian cats — are "hypoallergenic," but no cat or dog breed is completely allergy-free. All pets produce allergens, primarily found in their dander (dead skin flakes), saliva and urine — not their fur.

A study published in Annals of Allergy, Asthma and Immunology  found there is no such thing as a hypoallergenic pet, despite what breeders claim. This means that fur length or breed type does not determine how much allergen a pet produces.

Instead of relying on breed selection, the best approach is to focus on minimizing exposure and managing symptoms if you have pet allergies.

The future of pet allergy research

Given how common pet allergies are, it’s no surprise that scientists have spent decades studying how pet allergens affect health, why some people react more than others, and whether tolerance can be built over time. Their research has helped millions of people better manage allergies while preserving the important bond between pets and their owners. However, more studies are needed to improve the accuracy of allergy testing, develop better immunotherapy treatments and explore new approaches to help people with pet allergies live comfortably with their animals. 

More information on pet allergies can be found here.

About the expert

Dr. Todd Mahr is the executive medical director at the American College of Allergy, Asthma & Immunology.