Indoor Allergens (cont.)
What about allergies to molds?
Symptoms of hay fever (allergic rhinitis) and asthma can be caused by the inhalation of the spores of molds. Molds, or fungi, tend to grow on wet surfaces, either indoors or outdoors. The body of the mold produces spores or seeds, which are smaller than pollen and less potent as allergens. Large amounts of mold spores can be found in the air, especially in the spring and fall. They are usually most abundant at night, especially when it is damp, foggy, or during the rainy season.
Outdoor molds thrive in the soil, grass, dead leaves,
haystacks, barns, and stables. They are often found in
greater concentration when a hedge is located against a
house, especially in shady areas.
Indoor molds can congregate in bathrooms, especially in
the shower stalls, damp cellars, drains, potted plants,
closets, attics, house foundations, crawl spaces, and
sealed-off rooms. A "musty" smell often radiates from
these areas. On indoor plants, it is often the mold
overgrowth and not the flowers that cause allergy.
What about allergies to pets?
The "dander," or skin shedding, of an animal is more
potent in causing allergic reactions than the animal's fur
or hair. In addition to the skin sheddings and fur,
allergic reactions can occur to the saliva and/or urine of
cats, dogs, horses, and rodents.
The scope of the animal allergy problem is enormous.
These allergies are believed to affect up to 20% of North
Americans and are directly related to the increasing
popularity of pets, particularly cats and dogs.
Cats
The most well-known indoor allergy is probably due to Felis domesticus, the domesticated cat. The main allergen
is a protein that is produced by the sweat glands
(sebaceous glands) in the skin and appears in the skin
flakes or dander that are shed from cats. The allergen is
also found to a lesser degree in the fur, saliva, and
urine of cats. Even with a past history of tolerance to cats, it
is possible for a person with an allergic tendency to
develop a sensitivity to cats after constant exposure.
The cat dander allergen is not only confined to the cat
but also clings stubbornly to carpets and furniture. The
protein can linger there for months and can serve as a
reservoir from which allergens can become airborne when
disturbed. The allergen is also lightweight and can float
in the air for hours. People can also carry the cat
allergen around on clothes, thereby spreading it to work,
school, or a friend's house. Accordingly, for those who are allergic to cats, it does not reduce the risk of allergic reaction to simply isolate the cat in another room of the house. The cat dander is present wherever the cat generally exists, and it is this dander that is the problem.
Allergy
facts
- An estimated 30% of households in North America have at
least one cat.
- About 6% of the population is allergic to cats.
Dogs
Domesticated dogs (Canis familiaris) are found in over
40% of homes in North America. About 33% of allergic
individuals are sensitive to dog dander (as compared with
almost 50% of allergic individuals who are cat-allergic).
Since the allergic reaction is prompted by skin shedding
and not fur, it makes little difference whether the dog has
long or short hair; you can be as allergic to a Chihuahua
as you can to a sheepdog. Small dogs can also cause as
many allergy symptoms as large dogs. There is certainly no
evidence that one species is less allergy-provoking than
another one. Clearly, no breed is non-allergenic. Even
poodles and wheaten terriers (often thought to be
hypoallergenic) will likely induce allergy symptoms in
sensitive individuals upon continuous exposure.
If your child has asthma and a known allergy, be
especially
careful not to allow the child to spend the night at the
home of a friend or relative with a pet. Severe allergic
reactions and even fatalities have been reported. Do not
let this happen to your family or your
friends.
Horses
Only 10% of allergic individuals have a sensitivity to
horses. The reason is probably due to less exposure since
there is little horsehair in furniture or bedding anymore.
Sensitive people, however, must avoid not only horses and
stables, but also objects directly related to them, such as
bridles, saddles, and riding clothes. Also be aware that
horsehair may still be found in antique furniture and old
toys. People who have problems with horses may also react
to donkeys, mules, and zebras.
Allergy
alert
Remember that a trip to the barn not only exposes you to
animal dander, but also to mold, pollen, and lots of other
irritants as well. If you are an asthmatic, be careful and
be prepared.
Birds
Allergy to birds is more common among bird breeders
where the exposure is highest. People who are sensitive to
the feathers of chickens, geese, turkeys, and ducks can
still eat their meat or eggs. They may well react,
however, to the feathers in down comforters, pillows, and
duvets. You should also remember that dust mites hide in
these bedding accessories.
Rodents
This family includes hamsters, rabbits,
guinea pigs, gerbils, ferrets, mice, and rats. Most
allergic reactions are caused by exposures in laboratories,
but these animals are also common pets. Mouse urine is an
especially potent allergen for personnel that handle
laboratory animals. The urine of rats and guinea pigs also
contains allergens as do the saliva and fur of rabbits.
Rabbit hair can be found in fur coats, glove linings,
slippers, foot muffs, pillows, and quilts. The fur of the
Angora rabbit is said to be 10 times warmer than that of
sheep wool. The soft yarn spun from Angora rabbit fur can be
found in hand-knitted trimming, crochet work, gloves,
hosiery, and knee pads. Alone or mixed with silk, it is
also used in sportswear. And, of course, rabbits often
appear in schools as the classroom pet.
Allergy alert
Frequently, parents will report that their child
has "won the privilege" of caring for the classroom pet
over the weekend or the holiday vacation. This often leads
to the onset of a particular animal sensitivity. If you or
your child already has allergies or asthma, do not
volunteer for the job.
Next: What about allergies to indoor pollens and houseplants? »
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