The Australasian Society of Clinical Immunology and Allergy

Allergies to pets, particularly to cats and dogs, are a common cause of allergic disease, including asthma and allergic rhinitis (hay fever).

The main source of cat allergen is in the sebaceous glands in the cat's skin

Cats often lick themselves and as the main source of cat allergen is in the sebaceous glands, the licking helps spread the allergen.  Cat allergen is sticky, and glues itself to hairs, dust particles (forming a persistent aerosol) and all parts of the home. As all cats have sebaceous glands, all cat breeds can potentially cause allergies.

Even after removal of the pet, cat allergen can remain distributed throughout the home for up to 6 months and in the cat's bedding for up to 4 years. The allergen is so pervasive that it can even be measured in the homes of non-pet owners and on the clothing of co-workers who don't have pets. Cat allergen has even been detected in the Antarctic, even though cats have never been there.

In dogs the main source of allergen is saliva

As the main source of dog allergen is saliva, dander (shed skin particles) and hair can both help spread the allergen. Therefore all breeds of dog can potentially cause allergies, although some may not shed as much hair and dander (and therefore allergen) as others.

Allergies to other animals

Although not as common as cat and dog allergy, allergies to other animals including horses, mice, rats, rabbits, guinea pigs and birds are important. Transmission of these allergens on clothes and other items may be sufficient to trigger allergic rhinitis (hay fever) and asthma.

Testing for allergies to animals 

It is important to note that up to 50% of people who are allergic to animals do not get immediate symptoms. If there is some doubt as to whether or a pet (your's or someone else's) is causing your allergy symptoms, your doctor can confirm your suspicion using skin prick tests or allergen specific IgE (RAST) allergy tests. You may be referred to a medical specialist (Allergist / Clinical Immunologist) for allergy testing.

In children a negative allergy test does not mean that a child won't become allergic to pets later.

Some studies have suggested that increased exposure to cats and dogs may be associated with reduced sensitisation and allergic disease, whilst other studies have found that increased exposure is associated with increased sensitivity.  It should however be clarified that in people with established allergic disease who are already sensitised to animals, avoidance is well documented to prevent or reduce symptoms.

What can be done to prevent pet allergy?

Changes that are simple to implement and have been proven to be effective are as follows:

• do not bring a furred pet into the home
• find an existing pet a new home
• do not smoke, as exposure to environmental smoke makes a range of allergies (including pet allergies) more likely to develop.

Changes that are difficult to implement or have not yet been proven are as follows:

• restrict the pet to one area
• keep the pet out of the patient's bedroom
• use high efficiency air cleaners, either central or portable
• remove carpet or other reservoirs for allergens in the bedroom
• wash pets weekly.

Other options

In cases when it is difficult to avoid exposure to an animal, treatment options include medications such as intranasal cortocosteroid sprays (INCS) and/or antihistamines and possibly immunotherapy (desensitisation) in some cases.  Immunotherapy should only be initiated by a medical specialist (Allergist / Clinical Immunologist). 

Further reading 

1. Allergen avoidance
www.allergy.org.au/content/view/187/126/    

2. Allergy Prevention in Children
www.allergy.org.au/content/view/182/127/    

3. Immunotherapy
www.allergy.org.au/content/view/148/128/  

4. What is causing your allergy?
www.allergy.org.au/content/view/120/125/  

© ASCIA 2010

The Australasian Society of Clinical Immunology and Allergy (ASCIA) is the peak professional body of Clinical Immunologists and Allergists in Australia and New Zealand.

Website: www.allergy.org.au

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Postal address: PO Box 450 Balgowlah, NSW Australia 2093

Disclaimer

This document has been developed and peer reviewed by ASCIA members and is based on expert opinion and the available published literature at the time of review.  Information contained in this document is not intended to replace medical advice and any questions regarding a medical diagnosis or treatment should be directed to a medical practitioner. The development of this document is not funded by any commercial sources and is not influenced by commercial organisations. 

Content last updated January 2010