Pollen & Environmental Allergies

Tree Pollen Allergies

Airborne pollen is one of the most annoying and common allergens, and it causes 35 million people to suffer from upper respiratory allergy symptoms each year. A little over 5 million (fifteen percent) of these people suffer from spring seasonal tree pollen allergies.

Pollen allergy is one of the most common chronic diseases in the United States. The seasonal variety of pollen allergies is commonly referred to as hay fever (which has nothing to do at all with hay or with fever), but many doctors reserve this term for the specific allergy to ragweed which pollinates in the fall. Allergies that occur in the spring are usually a result of either grasses (85%) or tree pollen (15%) and spring allergies are sometimes referred to as rose fever (again nothing to do with roses or fever.)

Of the more than 50,000 species of trees worldwide, there are 600-700 native to North America; only pollen from about 65 of these has been shown to cause allergies. Most people are aware of their seasonal sensitivity, but may not know what the specific cause is (i.e. tree pollen, grass pollen, or molds). Accurate diagnosis should always include on detailed patient history and testing by your allergist.

Each spring microscopic oval and circular tree pollen particles are released to hitch a ride on currents of air. Their mission is to fertilize other trees of the same species. Insects do this for some trees but for most the wind is relied on. Small, dry and light, pollen granules have been known to travel as far out as 400 miles out to sea and up to two miles high in the air. Because the airborne pollens can travel so far, it does little good to remove the offending tree ‚ pollen can drift in from miles away.

These lightweight windcarried pollens enter noses and throats to trigger allergic reactions characterized by irritation of the eyes, nose and throat. In more severe reactions lungs become affected as well.

Occasionally those with allergic reactions to tree pollens may also cross react to certain raw fruits such as apples, plums and pears (though these foods may be less allergenic when cooked). Food cross reactions are usually felt as itchiness in the mouth and throat.

Tree pollens generally show little cross reactivity among themselves. You must develop an allergy to each specific tree pollen in order for it to cause symptoms. If you are sensitive to oak, you are not necessarily allergic to cedar. There are two families of trees that are an exception to this; the family that contains oaks, beeches, and birches and the family belonging to the cedars and junipers. If you are allergic to the pollen of one of these trees, you will probably experience symptoms from one or more members of the same family.

In the southeast Texas region the tree allergy season begins in February and lasts sometimes until late June. Pollens from ash, box elder, cedar, elm, hickory, juniper, oak, maple, and pecan are the primary allergy culprits.

Pine trees are one of the most noticeable producers of large amounts of pollen, however pine trees are less of a culprit than you would think. Pine pollen, the common yellow powdery dust is heavy and falls to the ground immediately so these trees are bothersome only if you live beneath them. (Citrus trees have heavy pollen as well.)

A little horticultural engineering can cut down offenders in the immediate environs. Asking your nursery for hybrid varieties that produce no pollen reduces the exposure but basically there is no real easy way to avoid windborne pollen.

Tree pollen counts tend to be higher on warm, dry and breezy days than during chilly, wet periods. Remain indoors when pollen counts are at there highest, particularly the early morning, late afternoon and early evening. Because of the microscopic size of tree pollens, most inexpensive masks sold at drug stores do not prevent pollen from sneaking in around the edges.

Often common, over-the-counter antihistamines are how many people find relief from tree pollen allergies. Newer antihistamines which do not cause drowsiness are available by prescription. Topical corticosteriods are valuable in the form of nasal sprays such as Beconase, Nasacort, Rhinocort and Flonase. If used consistently during the hay fever season they are very effective relieving nasal symptoms, with no major side effects.

Topical (local) nasal decongestant sprays can be used only occasionally, but never regularly because they cause rebound congestion. In the long run, decongestant nasal sprays can exacerbate rather than reduce tree pollen symptoms and should only be used according to the directions and with caution.

Antihistamines work well to relieve symptoms, but remember that some induce drowsiness and can interfere with driving, work and other activities. Recently approved prescription antihistamines such as Claritin can be very effective and not cause drowsiness.

Immunotherapy, or a series of allergy shots, is the best therapy for long-term relief. Most patients will have a significant reduction in their allergy symptoms within 9-12 months of starting their immunotherapy. As better allergens for immunotherapy have been produced in recent years, this technique has become an even more effective treatment.

Knowing when pollen counts are the greatest, paying attention to the instructions on your medication and carefully following the advice and treatment of you allergist should help see that the next allergy season is a breeze, not a sneeze.

Flowering Plant Allergies

People are generally not allergic to flowering plants, because they are bee pollinated, not wind pollinated. This is why they have bright colors, in order to attract bees. If you sneeze around flowers, it may be that you happen to be allergic to what may be pollinating nearby or that the smell of the flowers, much like perfume, is bothering your nose.

Grass Pollen Allergies

When "spring is in the air," grasses and flowers begin to revive, releasing copious amounts of pollen into the air in an annual ritual of survival.

But survival for these plants means misery for many allergy and asthma sufferers. Seasonal allergies keep many people indoors in hopes of avoiding pollens. Indeed, staying indoors does reduce one¼s exposure, particularly if electrostatic air intake filters are used to keep the indoor environment clean.

When going outdoors, remember that pollen levels are highest in the morning, and gradually subside as the day goes on.

For those who are not willing or able to stay indoors, there is still relief available. Prescription antihistamines, decongestants, and anti-inflammatory medications act to reduce symptoms. Immunotherapy (allergy shots) act to head allergies off at the pass by reducing the body’s sensitivity to allergens over a period of time.

The first step is accurate diagnosis. During the spring months, there are many grass pollens in the air, and the trees have still not finished their pollen performance.

Ragweed Pollen Allergies

Ragweed and hayfever have become synonymous in people's minds, especially during the cool Fall months. Ambrosia is the scientific name given to ragweed, and is from the Latin term for "immortal." This certainly seems true, because attempts to eradicate this hearty plant have met with little success.

The ragweed is a hairy, coarse looking plant that has no pretty flowers, an unpleasant smell, and no redeeming qualities. Its name was derived from the ragged appearance of its leaves. Short ragweed can bloom and spew pollen into the air when only a few inches tall, while the giant ragweed reaches twelve feet in height. Both thrive in soil that has been eroded or otherwise disturbed. The 1960 area's proximity to Cypress Creek and many construction projects make this a 'high risk' area for allergic individuals.

Another characteristic of ragweed is that the more hostile the growing environment, the more pollen a ragweed plant will produce. Stressful conditions and lack of rain shift the ragweed into a "procreation" mode; the plant then skimps on foliage and directs its resources into the bloom.

Allergy sufferers can run, but they can't hide from ragweed, as the pollen can travel for miles on the breeze. For those with the runny nose, congestion, itching eyes, headaches and cough associated with hayfever, we recommend surviving ragweed allergy by limiting exposure. Here are some tips to avoiding ragweed:

  • Remain indoors as much as possible during ragweed season. Pollen levels are highest in the morning hours.
  • Take a brief shower after outdoor activities to remove pollen from the skin and hair.
  • Keep windows up during automobile travel.
  • It may be helpful to install electrostatic filters in place of the standard fiberglass air-intake filters.

There are options available other than 'shutting out the world.' New prescription antihistamines, decongestants, and anti-inflammatory medications can alleviate the severity of allergic rhinitis symptoms while having fewer side effects than medications of years past.

And finally, there is desensitization through immunotherapy (allergy shots). This method of treatment is effective in most individuals who suffer from severe allergies, and offers a lasting remedy to this seasonal problem.

Ragweed pollen levels begin to decline in late October, and by late November are at a very low level... only to reprise their performance the next year!

Seasonal Pollen Allergies

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?

One 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.