Allergy to Domestic Pets


Throughout history man has had a close association with animals, both at work and in domestic life. However, contact with animals inevitably leads to exposure to animal allergens, and pets are now one of the major causes of allergic disease.

In the UK, pets are the second most important cause of allergy in the home with 50% of asthmatic children sensitised to the allergens of cats and 40% to dog allergen. There can also be reactivity to rabbits, hamsters and other furry domestic pets in these children.

Dog and cat allergy…

Dog and cat allergen is found in the animals’ saliva, sweat and urine. Animals frequently groom themselves so the allergens coat the hair and skin cells (dander), which, when shed, spread throughout the home or other buildings. Once the saliva dries, it becomes airborne very easily.

These allergens can be very persistent in the environment, with detectable levels found in homes where no pets have lived for many years, and dog allergen can be found in schools, having been brought there on the clothing and shoes of pupils and teachers. Cat allergen in particular is very ‘sticky’ in this way.

Despite popular belief, all dogs possess the allergenic material known to produce allergic reactions in humans, and therefore reported differences of sensitivity to different breeds probably relates more to level of exposure. Even breeds that are described as ‘hairless’ still have allergens found in dander from skin sources. It is possible that longer hair may harbour other allergens such as dust mite, pollens and moulds, to which an individual may also be sensitive. Other persons may be sensitive to substances found on the dog, such as flea powder or soaps.

Also, many dogs (and cats) have skin problems such as eczema, so because of their dry skin and irritation, spread larger amounts of dander.

Exposure to cats during a child’s first year of life is an important factor in the development of sensitisation to this allergen. Some studies have shown that children who grow up in homes with pets have more severe symptoms than those in homes without pets; other studies have shown that there may be a protective effect from growing up with pets. However, for those who have eczema, hay fever or asthma, removing pets is the best advice, even if there is no obvious allergy to them at present.

In dogs, routine and proper grooming, preferably outdoors, has been shown to greatly decrease shedding of hair and may decrease skin irritation and secondary bacterial infection. Grooming, preferably by someone other than the sensitive individual, should therefore be an important part of a management strategy for dog-allergic patients.
Bathing a cat once or twice a week can reduce cat allergens in the home by 90%. Confining a cat to one part of the house is unlikely to be effective as people will transfer cat allergens to other parts of the house on their clothes as they move around from room to room.


Other pets

Rabbits, small rodents and caged birds are very popular pets. Rabbits and guinea pigs are usually housed outdoors, whilst gerbils, hamsters, mice, rats and birds are commonly kept in the living room or even in the bedroom. These animals, especially budgerigars and hamsters, are particularly associated with allergic asthma. In small mammals, urine is the most potent source of allergen, and materials lining cages will be heavily contaminated. Allergenic chemicals will be released into the air as the animal moves around the cage disturbing the litter and bedding. As many of these are nocturnal creatures, activity such as racing around the cage and wheel means that very high levels of allergen are released into the air, usually in children’s bedrooms whilst they sleep, a frequent cause of allergy symptoms.

Fine dust in the air from bird feathers and droppings is not only associated with allergy but can, rarely, cause a more serious disease, ‘Bird Fancier’s Lung’, which results in a permanent scarring of the lungs. People who have bird aviaries are at risk from this.

Some people report problems from feather pillows. However, this reaction is usually not due to the feathers themselves but to house dust and feather mites.


  • Do not obtain any new pets.
  • Restrict pets to outdoors or to limited areas in the house – certainly not in the bedroom.
  • Wash cats and dogs regularly.
  • Keep your pets healthy and well-groomed (where appropriate).
  • People who are in contact with animals outside the home (e.g. horses, or other people’s cats) should change their shoes and clothes, and wash their hair, when arriving home.
  • If possible, remove carpets from rooms where pets are kept. Vacuum floors regularly. Remaining carpets should be cleaned with a high-temperature steam cleaner and vacuumed regularly with a high-filtration (HEPA) vacuum-cleaner such as those awarded our Seal of Approval endorsement.
  • Clean all surfaces (including walls) regularly.
  • Wash all pet bedding and baskets regularly.
  • ‘Allergy Control Solutions’ are available that alter animal allergens to make them less reactive. They can be sprayed on carpets and soft furnishings, and can be added to water when washing fabrics. Use in accordance with manufacturers’ instructions.
  • Products are also available to condition the animals’ skin and reduce the amount of allergen that is release into the environment (e.g. ‘Petal Cleanse’).
  • Consider using a good air filter to reduce allergen levels in the air, or ventilate rooms well.
  • Do not allow pets to lick your hands or face.
  • When returning from a walk during the spring and summer you should wipe your dog over with a damp cloth.


Follow these general pet hygiene tips to reduce your family’s risk of infection.

  • Wash your hands thoroughly. Always use an antibacterial soap after handling your pets (this is essential before preparing food).
  • Teach children to always wash their hands. You could wipe their hands with a cleaning wipe, especially before they eat anything.
  • Make sure children stay away from dog and cat faeces. Don’t let children play around a litter tray and stay clear of dog litter bins at the park.
  • Check that your pets are in good health. Immunisations should be up-to-date. Regular check-ups at the vets can also spot any possible infections.
  • Keep your pet’s fur clean. This may simply involve cleaning their paws if they’ve dug up any soil or a thorough shampoo after swimming in the local pond.