Auckland Allergy & Eczema Clinic

Cat Allergy

Cat Allergy

Cat allergy is by far the commonest allergy to pet animals and up to 40% of asthmatics are sensitive to cats. The cat allergen is much more likely to cause sensitisation than that of the dog.

The Cat Allergen

A tiny protein particle, the "Fel d 1" allergen is found mainly in the cat skin flakes and saliva. The protein is produced in the cat salivary glands and sebaceous glands of the skin. Cats are fastidious groomers, so they deposit the Fel d 1 protein on their fur by licking themselves.

An allergen is a material, which is capable of provoking an allergic reaction, such as pollen grain, dust mite or animal dander. Cat allergen — the allergy causing material from cats – is not cat hair but a protein present in the dander and saliva of cats. The allergens become airborne as microscopic particles, which when inhaled into the nose or lungs, can produce allergic symptoms.

Although individual cats may produce more or less allergen, there is no relationship between the pet’s hair length and allergen production, and no such thing as a non-allergic breed.

Male cats are more allergic than female cats, because testerone increases Fel d 1 production by the sebaceous glands. 

Where is Cat Allergen found?

Cat allergen is present in largest amounts in homes with cats, but has also been found in homes where cats have never been present and in offices or public spaces where animals are not allowed. Cat allergen is particularly sticky and is carried on clothing from places with cats to other locations. It is almost impossible to not be exposed to some level of cat allergen. Of course, levels of exposure will be much higher where cats are present, and these levels are more likely to cause allergic symptoms.

Because cat allergen particles are particularly small (1/10 the size of dust mite allergen), they remain airborne for prolonged periods of time. Cat allergic individuals are more likely to have a rapid onset of symptoms when entering a room with cats, because there is always allergen, which is airborne and can be easily inhaled. Opening windows, using exhaust fans and using high efficiency air cleaners, can decrease the amount of airborne allergen.

Soft furnishings, such as carpets, sofas and mattresses, will hold cat allergen even after a cat has been removed from the home or banished from the bedroom. It has been shown that it can take as long as 20 weeks for levels of allergen in carpets to decrease to levels found in a home without a cat, and up to 5 years for cat allergen levels in mattresses to decrease to such levels. Removal or treatment of the carpet or sofa, and encasing of the mattress, will reduce the continued exposure to these reservoirs of allergen.

Cat allergen is also found on vertical surfaces such as walls. Attempts to decrease cat allergen exposure in a home should include wall cleaning. If the cat is removed to a restricted area of the home, it is important to realise that airflow through the duct system in a hot air heated home could spread the allergen. Efficient vent and furnace filters could help trap the allergens and reduce the spread.

Manifestations of Cat Allergy

  • Immediate rhinoconjunctivitis and wheezing on entering the room with a cat. This is the most easily recognised feature of cat allergy.
  • Delayed- type reaction presents after cat exposure or persisting for weeks after. It is important to know that with all allergic reaction there is an immediate (occurring within 1 hour) and a delayed (occurring 2-4 hours) later. In cat allergy the immediate reaction might be subclinical and only the delayed reaction is clinical. So an asthmatic might notice worsening of their asthma the day following a visit to their relation who has a cat.
  • Chronic Severe Unstable Asthma 
    Many patients do not get acute flare up of their asthma with cat exposure and they assume that they are not allergic to their cat. In this situation there is ongoing chronic inflammation in the lung due to ongoing cat exposure.
  • Contact Urticaria
    Hives at the site where the individual comes in contact with cat fur or saliva.
  • Worsening of Atopic Eczema Cat allergen is a common trigger for atopic eczema.
  • Perennial Rhinitis
    Patients with a "permanent cold" could be reacting to their cat.

What can be done to help Cat Allergy?

Addressing the Cat

  • Daily grooming will help remove loose hair and dander
  • Bathe the cat weekly with plain water (reported to be better than soap and water) as this has been shown to remove much of their surface allergen, and significantly reduces the amount of future cat allergen produced.
  • It is not necessary to submerge the cat or to use detergent. Simply place the cat in the sink, and pour a pitcher of comfortable temperature water over its body. Washing should be done weekly for three weeks, then at 2-3 week intervals. Kittens usually do not mind getting washed. Mature cats should be gradually "conditioned" to being washed.
  • Avoid anything (fleas, mites) that will cause your cat to scratch, since this is where dander comes from

Addressing the Home

  • Cats should be restricted to as few rooms in the home as possible.
  • Cat dander settles onto carpets and soft furnishings, which act as a reservoir for the allergen, releasing it back into the air when touched. Remove the carpeting, if possible.
  • If carpeting cannot be removed, a denaturant solution of 3% tannic acid can be applied after the pet has been restricted to another room
  • Install HEPA (High Efficiency Particulate Air) filter cleaner in as many rooms as possible, starting with the bedroom. Air cleaners of this type can reduce the level of airborne cat allergen by about 50%. It is important to place the unit away from furnishings and not directly on the carpet so as not to disturb settled allergen.
  • Vinyl or hardwood floors instead of carpets & minimise upholstered furniture and fleecy surfaces. HEPA vacuum all fleecy surfaces including carpets.
    Mattresses and pillows are also a reservoir for cat allergen and should be encased in allergen-impermeable covers.
  • If possible, keep the cat out of doors all or some of the time, or limit it to a single area of the house. 
  • Ventilate the home. Very insulated, "energy efficient" homes actually trap animal dander inside. Opening windows and using exhaust fans can help increase air exchange and decrease air borne allergen. 
  • Keep the bedroom cat-free at all times — no exceptions
  • Vacuum carpets with HEPA equipped vacuum cleaner. This will reduce the allergens by up to 90% over standard vacuum cleaners.
  • Wear a dust mask when vacuuming.
  • The exhaust from a standard vacuum cleaner will stir up the allergens. Ideally vacuum while the allergic person is away from home.
  • Consider using a damp mop to clean the walls & furniture
  • Air the house as often as is possible. 

Addressing the Allergic Person

  • Do not assume, that because you do not get acute flare-up of your allergy when exposed to your cat that it is not causing chronic, ongoing inflammation. Have a skin prick test to find out.
  • Wash hands after touching the pet, and change clothing after contact with the pet.
  • Use a facemask when brushing, cleaning or changing the kitty litter.
  • Non-sedating antihistamines taken 1 hour before visiting homes with cats can be helpful.
  • Immunotherapy can reduce sensitivity to cats. For cat allergic people who work with animals, like vets or severely cat allergic children whose symptoms correlate with cat exposure, immunotherapy should be offered as an effective non-drug therapy. There are several studies showing long-term benefit from desensitisation to cats.