Cat Dander Allergy
Read any article on allergy and asthma triggers. What do you find? Avoiding cat dander as well other animal dander and allergens tops every list of recommendations. Perhaps you or someone in your family has allergies and asthma. Is cat dander and allergen a real threat to your health? Should you be concerned? What action can you take to protect your own and your family's health?
If you ask any general member of the public about cat allergens you'll quickly realize there is a great disparity of opinion. This is due of course to myth and misinformation that has spread unchecked by facts and proper education on allergic health care.
Some say cat dander is the cat hair. Others claim it is the dried saliva. Some people say there are low dander or no dander cat breeds. Many persons expose themselves or other allergic persons to cat dander and allergen believing it's just a minor inconvenience, not a serious health threat.
It's time we clear the air. In this article we'll discuss the facts surrounding cat dander and allergen: what it is and how it becomes a problem.
What is cat dander and cat allergen?
First of all, let's address the issue of dander. Put simply dander is dead skin cells, whether individually or sloughed off in sheets or clumps. Every living thing with skin has dander. We humans lose skin cells in flecks and flakes all the time. Sometimes we see them as the ashy residue on our dry skin or as dandruff from our scalp. In fact, the word dandruff comes from the same root as dander.
When we speak of dander though, we are usually referring to an animal. The hair an animal sheds is not dander. The length of the hair, long versus short, makes no difference in the amount of dander produced. In the case of cats, the dried saliva on their hair or which may be airborne is also not dander. Dander is the dead skin cells the cat or other animal loses as a part of their normal skin cell growth cycle.
New cells are constantly being created in the lower portion of the epidermis. These gradually push their way up to the surface and surface cells die and are sloughed off. The typical cat, or dog for that matter, has a twenty-one day cycle of cell growth though some animals, particularly breeds with problem skin can have growth cycles as short as 3 to 4 days.
These facts point to the absurdity of any claim for a cat with no dander or even a low dander breed. The poor cat would have to have no skin at all to be a dander free cat. Either that or our dander free cats would have to never renew their birthday suits at any time in their lives. Cats, whatever the breed, all have essentially the same skin growth cycle with any exception being a faster cycle that would result in higher than normal dander levels. It should also be pointed out that older cats are considered to be higher producers of dander than younger cats. This is explained as a result of a tendency to drier skin on older cats.
What makes cat dander a problem?
Apart from the fact that cat dander is a carrier mechanism for cat allergens, which will be discussed in more detail later there are several additional aspects to the problem that should be considered.
First of all, even a single cat produces sufficient dander to provide a plentiful food source for dust mites. These dust mites serve as a secondary source of allergens through their droppings and their dead, dried up carcasses as they die. Not only should the impact of cat allergens and dander be considered, but also the health effects of increased dust mite populations.
All animal dander is tiny, but cat dander is particularly microscopic. This presents several challenges to its control. If you've ever noticed dust in a shaft of sunlight the particles you were seeing suspended in the air were typically in the 50-micron size. Under ideal conditions of lighting and appropriate background, the unaided human eye might be able to make out particles as small as 10 microns. Approximately 75% of cat dander particles are 5 to 10 microns and 25% are 2.5 microns or smaller. At that size particles do not readily settle out of the air and tend to remain suspended for long times. They are also easily disturbed and made to become airborne or aerosolized.
This is a real problem when doing basic house cleaning or when actively seeking to clean up the dander and allergen. Studies have shown that vacuum cleaners can easily aerosolize cat allergen present on the floors and carpets to critical levels. As an example, in clinical studies of asthma, a nebulizer may be used to provoke an asthmatic response of a 20% Fall in Expiratory Volume (FEV). The quantity of allergen aerosolized by such a nebulizer would be on the order of 40 nanograms per cubic meter of air.
Repeated studies in a test house showed that domestic cleaning and vacuuming produced this same level of contaminant per unit volume of air. For asthmatic persons, the exposure levels to cat dander and allergen during household cleaning could easily result in a trip to the emergency room, or the morgue, depending on their overall control of their asthma. It is highly recommended that any household with a cat make use of a high quality HEPA vacuum. Effectiveness in controlling cat allergen dispersal can vary widely depending on how well the HEPA vacuum is constructed. The best HEPA vacuums can keep airborne allergen to a bare minimum.
The size of cat dander particles means they fall into the category of lung penetrating particles, particles that easily transport to the innermost recesses of the lungs. Since they are not just particulate irritants, but for the allergic individual, an immunological irritant, they can do significant cumulative damage. Chest X-rays of allergic individuals have found that long-term exposure to cat dander results in nodules forming inside the lungs. Reduced lung function and permanent lung damage are the results of this kind of long-term exposure to an allergenic lung-penetrating particle.
This should be of special concern to parents of cat allergic children, because children's lungs are still growing and tend to be even more sensitive to airborne contaminants. Children also tend to consume larger volumes of air per unit of body weight than do adults, so contaminants can have a more pronounced effect on children due to the higher concentrations that accumulate in their bodies.
The particle size of cat dander also presents a challenge because at that size range particles tend to stick to surfaces by virtue of molecular adhesion as opposed to simple gravity or friction as would be the case with lint stuck to a surface. This molecular adhesion renders particles especially sticky. For this reason, once a surface or article of clothing is contaminated with cat dander and cat allergen it tends to stay contaminated until vigorous cleaning has been performed. More than light dusting is required, the particles are best removed by scrubbing and the use of some kind of chemical cleaning agent to help release them.
The stickiness of cat allergen particles has resulted in cat allergen being found in homes, schools, offices, and government buildings where cats have never been. Riding in upon the clothes of cat owners, these cat dander and allergen particles constitute an all-pervasive background of allergen that is sometimes sufficient to cause allergic reactions in sensitive persons.
It should be pointed out now that dander particle size makes a HEPA based air purifier the best choice for reduction of airborne dander particles. HEPA's 99.97% filtration of 0.3 micron and larger particles is fully able to handle the 1 to 10 micron size typical of cat dander and makes them the perfect air purifiers for pet dander. The possibility of increased adhesion to lung tissues of lung penetrating particles that have been negatively charged should dissuade the consumer from purchasing a negative air ionizer type of air cleaner. Ionic style electrostatic precipitators that generate ozone and ozone generators themselves should also be avoided.
Ozone can induce an increased sensitivity to allergens that will make airborne cat allergen all the more potent to the unwary consumer. Ozone will also not clean particles from the air. Electrostatic precipitators are only about 80% efficient with clean, unloaded plates. Their efficiency can drop to below 20% in as few as three days due to plate loading of particles, thus requiring constant maintenance cleaning. The allergic member of the household should not perform this maintenance cleaning. The concentrated allergens could provoke a severe reaction if inhaled while trying to clean the plates. Cat allergen can also provoke skin rashes in allergic persons who come in physical contact with it. The only air purifier to remove pet dander safely and effectively is a HEPA type air purifier.
So, What is this Cat Allergen?
As problematic as the cat's dander is, it's not the root of the allergic problem. The dander is merely the free ride that the cat allergen hitchhikes on. Research has uncovered a total of 12 separate allergy-causing proteins in cats. The most significant one is termed Fel D 1 (Felis domesticus allergen 1). This is the allergen that afflicts some 80% of all cat allergic individuals. Though it has been extensively studied, perhaps more than any other animal allergen, its actual biological function in cats is completely unknown. What is known is that tip to tail every fiber of the cats being seems glued together by the stuff. It is found in their sebaceous glands where it secretes onto the skin and hair follicles.
This is a key way by which the dander becomes allergen contaminated. It is in their salivary glands where it contaminates the saliva they use when grooming themselves. This saliva then dries and becomes airborne, aggravating our allergies. It is found in the lachrymal glands (tear ducts). It's in the cat's anal glands, breast milk, urine, feces, and blood. Researchers believe that it is hormonally related because males tend to produce more than females or castrated males. The fact that it is such an integral part of cat biology precludes there ever being a low allergen, let alone hypoallergenic, cat breed. The best you can do is to choose a female over a male.
The quantity of Fel D 1 shed by cats easily overshadows all other allergens for sheer volume. Research in Japan found that Fel D 1 concentrations were 160 times those of dust mite allergen. Coupled with the fact that Fel D 1 is also more potent than dust mite allergen and you have a recipe for much misery for the allergic or asthmatic sufferer.
Additional allergens that cats are partly responsible for include those produced by their parasites. In particular, fleas are allergenic insects that contribute to the allergen load found in household dust.