Allergies: cat is out of the bagComment on this story
Durban - Pets, by way of their close daily contact with humans at home, may provoke allergies.
These allergies are commonly to cats and dogs, but can also be to rats, mice, guinea pigs, rabbits, hamsters, birds, as well as farm animals such as horses and cows.
Microscopic protein particles, called allergens, are present in animal skin flakes (animal dander). These can set off allergic symptoms when breathed into the nose and lungs or deposited in the eyes.
The animal fur, although itself not allergy-provoking, can collect dust, pollen, mould as well as other allergens.
The removal of a much-loved pet from the home may cause major emotional upsets. However, failing to remove a pet from the home of a child with severe asthma and documented sensitivity to that pet will result in needless suffering.
After the pet has left, it may take months for allergen levels in the home to fall sufficiently, so as not to set off allergic reactions. It may therefore be wise to remove the allergic person from the pet’s environment for a trial period (one to two weeks) to see if the symptoms improve. Skin and blood tests may also be used to test for specific pet allergies.
Cat allergy is the most common pet allergy, and up to 40 percent of asthma sufferers are sensitive to cats.
A tiny protein particle, the “Fel d 1” allergen, is found in the cat’s skin flakes and saliva. This is deposited on the fur by the cat licking itself, and is shed into the air and deposited on walls and clothing in the home. The cat allergen may remain airborne for months, due to its small size. If breathed in by the allergy sufferer, it will lead to an allergic reaction within minutes. These allergic reactions usually include itchy eyes and nose, sneezing, asthma and itchy skin rashes.
In some studies it has been shown that more than 80 percent of asthmatic children whose home contained a cat at the time of their birth and during the first year of their life, will develop a cat allergy.
The cat allergen can also cause allergies by being brought into homes where no cats live, for example on a person’s clothing. This has been noted to occur quite commonly in the classroom.
Removal of the cat from the home followed by thorough vacuuming of the carpets, floors and bedding is the only sure way of getting rid of its allergy-provoking protein.
If the pet must be kept, then washing the cat regularly (once a week) will considerably reduce the amount of allergen in the fur and in the home. Cats bathed from a young age tend not to mind being washed. The cat should also be kept out of doors as much as possible and banned from the allergy sufferer’s bedroom.
These measures, together with wiping down of the bedroom walls with a damp cloth to remove allergen deposits, regular airing of the home, and thorough vacuum cleaning, will reduce the level of cat allergen. A special exhaust filter should be fitted to the vacuum cleaner to prevent the small allergen particles from going straight through the machine and back into the air.
Face masks can be used when cleaning or brushing the cat, and clothes should be changed after contact with a cat. It can take up to six months to sufficiently reduce household levels of the cat allergen.
Dogs have a number of allergy-provoking protein particles in their saliva and skin scales. Dog allergy is less common than cat allergy, with longer-haired breeds provoking more frequent allergic reactions. A dog’s lick may set off an allergic response, as can breathing in the allergen particles.
With rabbits, rats, mice, hamsters and guinea pigs the most important sources of allergens are the saliva and urine. Once dry, these secretions become airborne and can be a source of allergic sensitisation for children and laboratory animal workers.
Horse and cow skin scales can be allergenic to those exposed to them. Birds carry allergy-provoking mites, moulds and pollen on their feathers. Budgie droppings can release proteins into the air which induce lung problems and asthma.
Tropical fish may be problematic, as individuals can develop allergies to ant’s eggs, used as feed, and moulds that may grow in the tank. Even the cockroach, although not considered a pet, is also a “source” of domestic allergic sensitisation.
Finally, when avoidance is not possible or can only be partly accomplished, medication may be needed. Oral antihistamines and topical sodium cromoglycate or corticosteroids can be used when nose and eye symptoms occur, while bronchodilators and inhaled sodium cromoglycate or corticosteroids can be used to control asthmatic symptoms. Hyposensitisation injections (immunotherapy) are of limited benefit for patients who wish to live or work with pets to which they are highly allergic. - The Mercury
* Written by Dr Adrian Morris of the Allergy Society of South Africa.