Pet allergy – can I still have a cat?

Allergies are widely reported to be on the increase, and with pet allergies affecting approximately 10-20% of the world’s population, they are a substantial problem. Allergies tend to be categorized as either outdoor (such as pollens) or indoor (such as animals). Cats have been found to be the second most common cause of respiratory indoor allergies. There has been some recent research into cat allergies, with some encouraging results as to how to help people with this difficult and growing problem.  

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Believe it or not, there are eight separate cat allergens recognized by the World Health Organisation! However, there is one main culprit: Fel d 1, which is the strongest allergen. 90-95% of people who suffer from a cat allergy have been found to be sensitive to this particular allergen.

Fel d 1 is secreted in both saliva and by the oil glands in cats’ skin. It is also present in small amounts in cat tears, anal gland secretions and urine. The Fel d 1 in the coat and on the skin (deposited from saliva during grooming, and from sebaceous glands) is then shed in large quantities via dander (skin flakes, debris and dried saliva) into the environment. It can remain airborne, but also settles into dust. It can also ‘stick’ to clothes and objects and be transferred into the wider environment, including non-cat owning homes, although it is found in the highest concentration in homes with cats.

Allergies can develop in babies and children, or can develop later in life as adults. However, once the allergy has developed you are likely to react any time you are exposed to a trigger. Signs of an allergy can take between minutes to hours to appear after coming into contact with the allergen. The pet does not actually need to be present for a reaction to develop: allergens can be present in the air or in the environment, such as dander or saliva on clothing or furniture.

The main symptoms are:

• Sneezing
• Runny nose
• Nasal congestion
• Post-nasal drip
• Red, sore and itchy eyes
• Cough/wheeze
• Red, sore or itchy skin on the face, chest, or any skin which has been in contact with the cat or its environment

These symptoms can be seen together or separately, and can vary in severity.

As with any allergy, there are multiple components to management, including: reducing exposure, medications and immunotherapy.

Remove the cat from the home

Houses which have pet cats living in them have much higher levels of Fel d 1 than other houses: up to 300 times higher! Removing the cat from the home will have a huge impact on the levels of allergen, although it can take months for levels to subside. However, although removing the cat from the environment is often advised by human healthcare professionals, it is not an attractive option for most cat owners!

Limiting the access of the cat to certain rooms

If re-homing the cat is not an option, limiting their contact with cat-allergic individuals and limiting their access to certain rooms such as bedrooms can help reduce the human occupants’ exposure to allergens. This may involve something of a balancing act: some cats will find restrictions on their movements, and on their amount of human interaction difficult, perhaps leading to frustration and behavioral issues. On the other hand, as dander can easily spread around the house, quite strict restrictions may be needed for this method to actually have some effect.

Cleaning the house

Strict measures to keep the home free from dust and dander can be effective at reducing levels of Fel d 1. These measures need to be performed rigorously and frequently for best control. Here are some suggestions, the more of them which can be done together will increase how effective this strategy is:

• Keep windows open where possible to increase ventilation
• Remove carpets and replace with hard floors
• Wash bedding and curtains frequently
• Wash/wipe down hard surfaces and floors frequently
• Vacuum floors and furniture twice weekly, with a vacuum cleaner which has a high-efficiency particulate air filter (HEPA)
• Use HEPA air filtration in the house
• Use laminar airflow over beds at night

These measures, along with frequent hand washing will help reduce exposure to cat allergens even when a cat is living in the home.

Immunotherapy to reduce active Fel d 1 shedding by cats

There have been some exciting new developments in tackling allergies to cats.

A novel vaccine has been developed recently that induces auto-antibodies to Fel d 1 in the cat, thereby reducing the amount of Fel d 1 that is secreted. Early studies have shown promise, but the safety of such a product needs to be tested more robustly, and it is not available commercially.

The newest approach to help cat allergy sufferers, and one that is now available, is a diet for cats which focuses on neutralizing the Fel d 1 after it has been produced by the cat, meaning although the cat still naturally produces Fel d 1, it doesn’t cause people with cat allergies to react. It does this by using antibodies from chicken eggs which block the IgE-binding sites on the Fel d 1 molecule and so block the human allergic response. The diet is a complete dry diet, with each piece of kibble coated in these antibodies. The antibodies then neutralize the Fel d 1 in the saliva before it is transferred via grooming onto the cat’s hair, and therefore into dander and the environment. Initial trials look very promising, and its use has been shown to significantly reduce active Fel d 1 found in hair samples from cats.

Cats shed Fel d 1 in their dander, so it makes sense that bathing them reduces this. Studies show that levels of allergen do reduce after bathing, but likely only for short periods of time. Baths are also often very poorly tolerated by cats. It may be that unless you have a very tolerant cat who can be bathed two or three times weekly, this one isn’t hugely practical or useful.

Various breeds and types of cat have been touted as ‘hypoallergenic’, and suitable for owners with cat allergies. However, while there is variability between individuals, it has been shown that all cats of all breeds produce Fel d 1 – with no significant differences being confirmed between breeds to date. Coat length, color and pattern all also make no difference. Somewhat surprisingly, it has also been found that the levels of Fel d 1 in the home environment do not appear to vary between houses where cats spend significant time outdoors to those where the cats remain indoors.

Although there is a wide variation in the amount of Fel d 1 produced between individual cats, entire male cats produce significantly more Fel d 1 than their neutered counterparts, and neutered males produce similar amounts to entire or neutered females.

There is no known breed that produces less Fel d 1, and therefore no specific breed which may improve living conditions for an owner with cat allergies. It is possibly more important to consider temperament: a cat desperate for human contact and plenty of cuddles is perhaps not as suitable for a home with an allergy sufferer. Therefore, breeds known to be more aloof, such as the Russian Blue or Persian might be better choices than choosing a breed solely for their coat length or skin type. However, all cats are individuals with both differing personalities and varying levels of Fel d 1, so it is very hard to predict what would work best in any given situation. Whichever breed or type, the best reduction in Fel d 1 is by not having an entire male, as their levels of Fel d 1 are much higher than neutered males or females.

Cat allergies are both common and increasing, and can cause a wide range of debilitating symptoms. However, the cat-human bond is often strong, and rehoming the cat is not always the chosen option to manage an allergy. There are now a range of options for managing the levels of the main cat allergen (Fel d 1) in the home environment, including new immunotherapy developments. Approaches such as this to reduce exposure to the allergen may be highly valuable alongside prescribed medications to control symptoms.