The Impact of Pets on Asthma

by John Bottrell Health Professional

The impact of pets on asthma is an interesting subject. On the one hand, evidence suggests exposure to pets may cause and trigger asthma. Yet on the other hand, evidence suggests exposure to pets may actually prevent asthma. So what gives?


Of the 235 million people with asthma worldwide, about 75 percent have allergies, and about 10 percent are allergic to household pets. Cats and dogs are the most common pets that cause allergies, although cat allergies are about 50 percent more common than dog allergies. However, along with cats and dogs, any warm-blooded animal has the potential to cause pet allergies.

What are pet allergies?

All warm-blooded animals produce dander (flakes of skin), urine, feces, and saliva. Exposure to proteins (allergens) in these substances causes the immune systems of susceptible subjects (the unfortunate 10 percent) to release proteins (called IgE antigens). These attach to mast cells lining the respiratory tract, eyes, and skin. Future exposure to that allergen will cause it to bind with an Ige antigen. This causes a series of chemical reactions that lead to inflammation of cells lining the eyes, nose, throat, and airways. This is what causes allergy symptoms: itchy and watery eyes, nasal congestion, itchy throat, coughing, sneezing, wheezing, difficulty breathing, and irritability. To learn more, read my post "Why Do Allergies Trigger Asthma? What Can You Do?"

What's the pet allergy-asthma link?

A common theory suggests that repeated or chronic exposure to any substance — such as pet allergens — that causes airway inflammation may lead to chronic airway inflammation, or asthma. Airways are now said to be oversensitive, or hyper-reactive. Subsequent exposure to the allergen will cause this chronic inflammation to worsen, causing the asthma response as well as the allergic response. To learn more, read my post "Do Allergies Cause Asthma?"

How are pet allergies detected?

One way is to be vigilant to what you were exposed to just prior to having an allergy or asthma attack. If you have a reaction after exposure to a pet, then chances are it's the culprit. Still, the best method is to be tested for allergies. Allergy testing is the only sure way of knowing if you have pet allergies.

What can you do?

The ideal treatment for pet allergies is removal of the pet from the home, and avoiding it in the future.

For pet lovers who simply cannot avoid their loving pets, the next best option is to:

  • Keep pets out of the bedroom and keep the door closed

  • Remove upholstered furniture and carpets, or keep pets off of these

  • Wash pets weekly to wash off potential allergens

  • Use High Efficiency Particulate Air (HEPA) filters to reduce airborne allergens

If allergies persist despite these efforts, the next best option is to work with your physician, who may recommend medicines such as antihistamines (like Claritin and Benadryl) or leukotriene antagonists like Singulair. Plus, it's always a good idea to work with your physician to obtain and maintain good asthma control.

Do pets prevent allergies?

It's a possibility. One study showed that exposure to cats prior to the age of 18 resulted in a 50 percent less chance of developing a cat allergy. Likewise, boys exposed to dogs in the first year of life had a 50 percent less chance of developing a dog allergy. There are some theories, and research is ongoing to better understand this. Learn more by reading my post "Having a Dog or a Cat May Prevent Asthma."

Bottom line: It's clear that pets may cause and trigger allergies and asthma, and that pet allergies may be prevented and controlled. What's not so clear is how pets might prevent allergies and asthma. So the full impact of pets on asthma has yet to be determined.

John Bottrell
Meet Our Writer
John Bottrell

John Bottrell is a registered Respiratory Therapist. He wrote for HealthCentral as a health professional for Asthma and Chronic Obstructive Pulmonary Disease (COPD).