What is Allergy?
Dust Mite Allergy
Each spring, summer, and fall,
tiny particles are released from trees, weeds, and
grasses. These particles, known as pollen, hitch rides on currents
of air. Although their mission is to fertilize parts of other
plants, many never reach their targets. Instead, they enter
human noses and throats, triggering a type of seasonal allergic
rhinitis called pollen allergy, which many people know as hay
fever or rose fever (depending on the season in which the symptoms
occur). Of all the things that can cause an allergy, pollen
is one of the most widespread. Many of the foods, drugs, or
animals that cause allergies can be avoided to a great extent;
even insects and household dust are escapable. Short of staying
indoors when the pollen count is high--and even that may not
help--there is no easy way to evade windborne pollen.
People with pollen allergies often develop sensitivities
to other troublemakers that are present all year, such as dust
mites. For these allergy sufferers, the "sneezin' season"
has no limit. Year-round airborne allergens cause perennial
allergic rhinitis, as distinguished from seasonal allergic rhinitis.
What is pollen?
Plants produce microscopic round or oval pollen
grains to reproduce. In some species, the plant uses the pollen
from its own flowers to fertilize itself. Other types must be
cross-pollinated; that is, in order for fertilization to take
place and seeds to form, pollen must be transferred from the
flower of one plant to that of another plant of the same species.
Insects do this job for certain flowering plants, while other
plants rely on wind transport.
The types of pollen that most commonly cause
allergic reactions are produced by the plain-looking plants
(trees, grasses, and weeds) that do not have showy flowers.
These plants manufacture small, light, dry pollen granules that
are custom-made for wind transport. Samples of ragweed pollen
have been collected 400 miles out at sea and 2 miles high in
the air. Because airborne pollen is carried for long distances,
it does little good to rid an area of an offending plant--the
pollen can drift in from many miles away. In addition, most
allergenic pollen comes from plants that produce it in huge
quantities. A single ragweed plant can generate a million grains
of pollen a day.
The chemical makeup of pollen is the basic factor
that determines whether it is likely to cause hay fever. For
example, pine tree pollen is produced in large amounts by a
common tree, which would make it a good candidate for causing
allergy. The chemical composition of pine pollen, however, appears
to make it less allergenic than other types. Because pine pollen
is heavy, it tends to fall straight down and does not scatter.
Therefore, it rarely reaches human noses.
Among North American plants, weeds are the most
prolific producers of allergenic pollen. Ragweed is the major
culprit, but others of importance are sagebrush, redroot pigweed,
lamb's quarters, Russian thistle (tumbleweed), and English plantain.
Grasses and trees, too, are important sources
of allergenic pollens. Although more than 1,000 species of grass
grow in North America, only a few produce highly allergenic
pollen. These include timothy grass, Kentucky bluegrass, Johnson
grass, Bermuda grass, redtop grass, orchard grass, and sweet
vernal grass. Trees that produce allergenic pollen include oak,
ash, elm, hickory, pecan, box elder, and mountain cedar.
It is common to hear people say that they are
allergic to colorful or scented flowers like roses. In fact,
only florists, gardeners, and others who have prolonged, close
contact with flowers are likely to become sensitized to pollen
from these plants. Most people have little contact with the
large, heavy, waxy pollen grains of many flowering plants because
this type of pollen is not carried by wind but by insects such
as butterflies and bees.
When do plants make pollen?
of the most obvious features of pollen allergy is its seasonal
nature--people experience it symptoms only when the pollen grains
to which they are allergic are in the air. Each plant has a
pollinating period that is more or less the same from year to
year. Exactly when a plant starts to pollinate seems to depend
on the relative length of night and day--and therefore on geographical
location--rather than on the weather. (On the other hand, weather
conditions during pollination can affect the amount of pollen
produced and distributed in a specific year.) Thus, the farther
north you go, the later the pollinating period and the later
the allergy season.
A pollen count, which is familiar to many people
from local weather reports, is a measure of how much pollen
is in the air. This count represents the concentration of all
the pollen (or of one particular type, like ragweed) in the
air in a certain area at a specific time. It is expressed in
grains of pollen per square meter of air collected over 24 hours.
Pollen counts tend to be highest early in the morning on warm,
dry, breezy days and lowest during chilly, wet periods. Although
a pollen count is an approximate and fluctuating measure, it
is useful as a general guide for when it is advisable to stay
indoors and avoid contact with the pollen.
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What is a Nasal Allergy?
The medical term rhinitis refers to a disorder
often characterized by symptoms including an itchy runny nose,
sneezing, and nasal congestion from a variety of causes. One
of the most common types of rhinitis is allergic rhinitis or
Before we discuss allergic rhinitis, one must better understand
what "allergy" is all about. Allergy is the opposite
of AIDS. Allergy symptoms are the result of too much immunity.
Your immune system produces antibodies to fight infection. Your
body is producing too much of an antibody known as E. The allergy
antibody E or (IgE) is made by your immune system in response
to an exposure to substances that we refer to as Allergens.
Allergens are usually environmentally stable foreign substances
like pollen protein that may induce allergic reactions but only
in predisposed individuals.
Why do allergic symptoms occur?
The allergic response starts when the immune
system (which is designed to protect the body from harmful material)
mistakes perfectly harmless materials (such as pollen and dust)
for potentially threatening "invaders." The defensive
process that follows starts with a group of specialized cells
known as mast cells.
Mast cells are located in various tissues in the body where
harmful materials can gain access - including the nose, eyes,
nasal mucosa, and lungs. Each mast cell contains chemicals,
such as histamine, that trigger the allergic response. When
histamine is released into your nose, you will sneeze and have
a runny nose. Histamine in the lungs will cause spasm of the
airways or wheezing. If histamine is released from exploding
mast cells into the skin, you may experience itching. If an
allergic reaction occurs all over the body, such as with a severe
life-threatening bee sting reaction, it is called Anaphylaxis.
As long as the body is not exposed to allergens, these chemicals
remain inside the mast cells, where they can cause no harm.
However, when a sensitive person is exposed to an allergen,
the mast cell membranes break down and the chemicals escape
(degranulation). Once the chemicals are released from the cells,
they go on to trigger the symptoms of allergic rhinitis.
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What is allergic conjunctivitis and what causes it?
A clear, thin membrane called the conjunctiva covers your eyeball
and the inside of your eyelids. If something irritates this
covering, your eyes may become red and swollen. Your eyes also
may itch or even hurt, and they may water. This is called conjunctivitis.
When an allergen is the cause of the irritation,
the condition is called allergic conjunctivitis. Some common
allergens include pollen from trees, grass and ragweed; animal
skin and secretions such as saliva; perfumes and cosmetics;
skin medicines; air pollution and smoke. Other causes of conjunctivitis
are viral and bacterial infections.
Will allergic conjunctivitis damage
No. Allergic conjunctivitis is irritating and uncomfortable,
but it will not hurt your eyesight.
What can I do to avoid getting the above
Try to identify and avoid the allergens that cause your symptoms.
For example, if you are allergic to pollen or mold, stay indoors
when pollen and mold levels are high. You can usually find out
when allergen levels are high from the weather report. Keep
your doors and windows closed and use an air conditioner during
the summer months.
How is allergic conjunctivitis treated?
Several types of eye drops are available to treat allergic conjunctivitis.
They can help relieve itchy, watery eyes and may keep symptoms
from returning. Eye drops may contain an antihistamine, a decongestant,
a nonsteroidal anti-inflammatory drug (NSAID), or a mast-cell
stabilizer. Some drops contain a combination of these. Some
eye drops require a prescription.
Antihistamine pills (which many people take
for their allergies) may also help. Your doctor will talk with
you about which treatment is right for you.
Do these treatments have side effects?
Many eye drops can cause burning and stinging at first when
you put them in, but this usually goes away in a few minutes.
It is important to remember that all medicines may potentially
cause side effects, so talk with your doctor before using any
medicine, including eye drops.
What else can I do to feel better?
It may help you to put a cold washcloth over your eyes for relief.
Lubricating eye drops (sometimes called artificial tears) may
also make your eyes feel better. You can buy these drops without
Can I wear my contact lenses?
Itís not a good idea to wear contacts while you have allergic
conjunctivitis, because you might get an eye infection. Instead,
wear your glasses until your eyes feel better.
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Allergic to Dogs
Steps Can Be Taken to Reduce Dog Allergens
Many people will ignore both chronic allergy symptoms and specific
medical advice in order to keep the family dog.
Who Is Susceptible?
Allergies to dogs can strike anyone at any age. Most people
that suffer from dog allergies often have other mild or moderate
allergies to pollens or molds. There is a strong genetic correlation
in developing allergies, so if your parents have allergies then
you are likely to have them also.
Is Any Dog Safe?
No dog is considered non-allergenic because all dogs produce
dander, saliva, and urine which are the offending allergens.
Any dog who sheds skin, urinates, or licks has the potential
to become a problem for an allergic individual.
There are dogs that produce less dander, however.
For instance, dogs that shed their skin about every 21 days
include poodles, airedales, and schnauzers.
Dog allergens can produce nasal congestion, runny nose, itchy
nose, sneezing, itchy and watery eyes, coughing, a scratchy
sore throat, itchy skin rashes or hives, headaches, fatigue,
difficulties in breathing, and asthma.
Be sure to always wash your hands after each time you touch
or play with a dog. You may even want to shower and change your
Dog allergens are small and sticky and can stay
airborne for a long time. They can adhere to walls, clothing,
carpet, furniture, and heating and cooling ducts. For this reason,
it is best to keep dogs away from the bedroom or any other rooms
you spend a lot of time.
Avoid using heavy carpets, large draperies,
and upholstered pieces that become collecting grounds for pet
allergen. If you have carpet, steam clean it several times a
year. Wash walls and baseboards also.
The use of HEPA room air cleaners and replacing
central heating/cooling system air filters frequently can help
reduce the allergen in the air. Dr. Adelglass recommends placing
a screen made of cheesecloth or other thin material over bedroom
vents to keep dander from circulating into the bedroom from
the central heating/cooling system.
Research has shown that if a dog is washed and
brushed frequently (not more than twice weekly), the airborne
allergens are cut drastically. This task should be done outside
of the home. Be sure the shampoo you use does not dry out the
dog's skin which may worsen the problem. Remember to also wash
the dog's bedding and toys.
Feed your dog a well-balanced diet which includes
some natural fat that helps reduce skin dryness and flaking.
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