Does a HEPA Filter Really Get Rid of Cat Dander?

What is Cat Dander?

Cat dander is microscopic particles of dead skin shed from a cat’s skin. Cat dander is made up of tiny flecks of skin and hair that cats shed constantly. According to the Lung Association, dander is composed of “skin flakes in addition to dried saliva and dried microscopic particles of urine.” Cat dander floats unseen in the air and is small enough to be easily breathed in. For people with allergies to cats, these dander particles can trigger allergic reactions.

Cat dander comes from two sources: sebaceous cells from the sebaceous glands in a cat’s skin, and epithelial cells shed by the epidermis layer of the skin. All cats produce and shed dander continuously as new skin cells replace old ones. The dander becomes airborne and builds up on surfaces around the house over time. Cat dander is so small it takes hours to settle and easily gets stirred up again by motion in the environment.

When inhaled by a person who is allergic, the protein found in cat dander triggers an immune response that leads to common allergy symptoms like sneezing, congestion, itchy eyes, runny nose, and wheezing. Asthma symptoms may also be triggered in people with asthma. For those with severe cat allergies, exposure to cat dander can potentially lead to anaphylaxis in rare cases.

Prevalence of Cat Allergies

Cat allergies are very common, with some estimates suggesting 10-20% of adults worldwide are allergic to cats (1). The prevalence seems to be increasing over time. Sensitization rates are typically around 5-20% in patients tested for allergies (2). Certain risk factors make people more prone to developing cat allergies, especially asthma and other allergic conditions like hay fever.

The most common symptoms of cat allergies include respiratory symptoms like sneezing, coughing, postnasal drip, and wheezing. Rashes, watery eyes, and runny nose are also common. In severe cases, some individuals can experience anaphylaxis. Symptoms usually start within minutes to hours of exposure and can persist even after the cat is no longer present (3).

Risk factors for developing cat allergies include having asthma, environmental allergies, or a family history of allergies. Children seem more likely to develop cat allergies than adults. Males may be at slightly higher risk than females. Exposure to cats early in life may increase risk as well.

In summary, cat allergies are quite prevalent worldwide and can cause uncomfortable or even dangerous symptoms in those affected. Certain groups are at higher risk, but cat allergies can develop at any age. Knowing the common symptoms and risk factors can help identify cat allergies promptly.





About HEPA Filters

HEPA stands for “high efficiency particulate air” filter. HEPA filters are a type of pleated mechanical air filter designed to trap over 99.97% of particles greater than 0.3 microns in size (EPA).

HEPA filters work by forcing air through a fine mesh that traps particles like pollen, pet dander, dust mites, and smoke. The mesh has submicron pores that capture particles through a combination of diffusion, interception, and impaction. As air passes through the filter, particles get stuck within the fibers of the mesh (Filtrete).

To qualify as HEPA, filters must remove 99.97% of particles 0.3 microns in size during testing. HEPA filters have different ratings based on their efficiency and resistance to airflow. The most common ratings are HEPA Type A, Type B, Type C, and Type D. True medical-grade HEPA filters are Type A, which are 99.97% efficient at 0.3 microns.

HEPA Filter Effectiveness Against Cat Dander

HEPA filters have been shown to be highly effective at removing cat dander and allergen particles from the air in controlled lab testing environments. In studies by the Department of Energy, HEPA filters removed over 99.97% of particles 0.3 microns in size, which includes the majority of cat dander particles (Source).

Real-world field studies in homes with pets have also demonstrated HEPA filters’ effectiveness. A study published in the Annals of Allergy, Asthma and Immunology found portable HEPA filter air cleaners reduced cat allergen levels in bedrooms by around 70% over 3 months of use (Source).

However, HEPA filters do have limitations when it comes to cat dander. They cannot destroy or permanently remove dander particles, only capture them. Frequent filter replacement is needed to maintain effectiveness. HEPA filters also do not remove odors associated with cat dander and secretions. Using HEPA filters alone may not completely eliminate symptoms for those highly sensitive to cat allergens (Source).

Proper Use of HEPA Filters for Dander

To effectively capture cat dander, HEPA filters must be used properly. Correct placement of the air purifier is crucial – it should be in the room where the cat spends the most time, typically a living room or bedroom. For best results, place the unit so airflow is not obstructed by furniture or walls. It is also important to change the HEPA filter regularly according to manufacturer recommendations, usually every 6-12 months depending on use. Operating an air purifier with a clogged filter allows dander to pass through into the air. While HEPA filters are highly effective at trapping dander, using them in combination with other allergy reduction methods can further reduce allergen levels. This includes frequent vacuuming, washing bedding on hot settings weekly, and grooming the cat daily to lower dander production [1].

Other Ways to Reduce Cat Dander

There are several methods to help reduce cat dander around the home in addition to using HEPA filters:

Bathing and grooming cats frequently can wash away dander and reduce shedding and buildup in the home. Investing in deshedding tools and brushing cats regularly helps remove loose hair and dander before it spreads. Products like moisturizing shampoos and allergen-reducing sprays and wipes can also help control dander when used properly [1].

Vacuuming carpets, furniture, drapes and other surfaces frequently using a vacuum with a HEPA filter can help remove dander from surfaces before it circulates in the air. Use damp microfiber cloths to wipe down walls and hard surfaces which attract dander [2].

High quality air purifiers with HEPA filters can trap dander floating in the air. Look for purifiers designed specifically for pet allergens. Running them regularly can filter dander out of the air before it is inhaled [3].

Specialized allergen-reducing products like sprays, powders and wipes can also help neutralize dander on surfaces and pets. These are formulated with ingredients that bind to allergens like cat dander to limit exposure.

Living with a Cat Despite Allergies

Living with cats when you have allergies can be challenging, but there are steps you can take to manage your symptoms. Some options include:

Keeping cats out of bedrooms – Keeping your bedroom a cat-free zone can help reduce exposure to allergens during sleep. Close doors and use barriers like screens to prevent access.

Washing hands after contact – Washing hands immediately after petting cats helps remove dander and allergens. Use soap and warm water and wash for at least 20 seconds.

Medications and immunotherapy – Allergy medications like antihistamines and nasal sprays can help control symptoms. Allergy shots and sublingual immunotherapy may increase tolerance over time [1].

Rehoming cat – In severe cases where allergy treatments are unsuccessful, rehoming the cat with a non-allergic family may be an option to discuss with your doctor.

Seeking a Medical Evaluation

If you suspect you may have a cat allergy, it’s important to seek confirmation and guidance from a medical professional. An allergist can perform allergy testing to determine if you’re allergic to cats specifically or other allergens as well.

Allergy testing methods may include a skin prick test, where possible allergens are placed on the skin and pricked lightly to observe any reactions. Blood tests can also detect allergy antibodies. These tests can help identify the specific allergens you’re sensitive to.

The allergist will also evaluate the severity of your allergy symptoms. Mild cases may be manageable with over-the-counter antihistamines and other precautions. More severe cases may require prescription medications or allergy shots for immunotherapy.

Treatment options focus on managing symptoms and reducing exposure. Antihistamines, decongestants, nasal sprays and allergy shots can provide relief. Allergists may also recommend allergen avoidance and creating an “allergy-proof” environment at home with HEPA filters, frequent cleaning, and keeping pets out of bedrooms.

While cat allergies can’t be cured, seeing an allergist can provide solutions for living more comfortably despite sensitivities. With proper treatment and care, those with cat allergies can still keep feline friends in their lives.

The Bottom Line

Based on the available evidence, HEPA filters can be an effective way to reduce cat dander in the home. Studies have shown that HEPA filters significantly decrease airborne cat allergens when used properly and maintained regularly. However, filters alone may not eliminate all dander, so additional recommendations include:

  • Keeping your cat out of bedrooms and limiting it to one area of the home
  • Vacuuming and dusting frequently using a HEPA filter vacuum
  • Washing hands after contact with your cat
  • Grooming your cat regularly to minimize loose hairs and dander
  • Using high quality air purifiers with HEPA filtration in rooms your cat frequents
  • Washing bedding and soft furnishings regularly in hot water

While HEPA filters can dramatically reduce dander levels, those highly sensitive may still react to low levels of allergens. Consulting an allergist can help determine your sensitivity and treatment options, including immunotherapy. With proper care and precautions, even those with moderate cat allergies may be able to successfully live with a cat.




MAYO CLINIC. Pet allergy.



AMERICAN LUNG ASSOCIATION. Air Filters and Air Purifiers.

Scroll to Top