1. What Types of Plants Produce the Most Allergenic Pollen?

The type of pollen that most commonly causes allergic reactions comes from plants (trees, grasses, and weeds) that typically do not bear fruit or flowers. These plants produce small, light, dry pollen granules in large quantities that can be carried through the air for miles.

Common plant allergens include:

Weeds, such as ragweed (including the marsh-elder, desert broom, feverfew, dog fennel, chamomile, chrysanthemum, and marigold families), sagebrush, redroot pigweed, lamb's quarters, goosefoot, tumbleweed (Russian thistle), and English plantain.
Grasses, such as timothy grass, Kentucky blue grass, Johnson grass, Bermuda grass, redtop grass, orchard grass, sweet vernal grass, perennial rye, salt grass, velvet grass, and fescue.
Hardwood deciduous trees, such as oak, ash, elm, birch, maple, alder, and hazel as well as hickory, pecan, box, and mountain cedar. Juniper, cedar, cypress, and sequoia trees are also likely to cause allergies.
2. What Does a Pollen Count Mean?

A pollen count is the measure of the amount of pollen in the air. Pollen counts are commonly included in local weather reports. The counts are usually reported for mold spores and three types of pollen: grasses, trees, and weeds. The count is reported as grains of pollen per square meter of air collected over 24 hours. This number represents the concentration of all the pollen in the air in a certain area at a specific time. The pollen count is translated into a corresponding level: absent, low, medium, or high.

In general, a "low" pollen count means that only people extremely sensitive to pollen will experience symptoms. A "medium" count means many people who are sensitive to pollen will experience symptoms, and a "high" count means most people with any sensitivity to pollen will experience symptoms.

Although the pollen count is an approximate and fluctuates, it is useful as a general guide when you are trying to determine whether or not you should stay indoors to avoid pollen contact.

3. Should I Consider Moving to Decrease My Allergy Symptoms?

No. Moving to a different geographic climate will not help "cure" allergies. Most people who relocate to get away from pollens that cause their allergies tend to find that they eventually develop allergies to the plant pollens in the new area.

4. How Can I Tell if My Son Has Allergies or a Common Cold?

Symptoms of allergies and colds can be similar, but here's how to tell the difference:

Occurrence of symptoms:

Both allergies and colds cause symptoms of sneezing, congestion, runny nose, watery eyes, fatigue, and headaches. However, colds often cause symptoms one at a time: first sneezing, then a runny nose, and then congestion. Allergies cause symptoms that occur all at once.

Duration of symptoms:

Cold symptoms generally last from 7 to 10 days, whereas allergy symptoms continue as long as a person is exposed to the allergy-causing agent. Allergy symptoms may subside soon after elimination of allergen exposure.

Mucus discharge:

Colds may cause yellowish nasal discharge, suggesting an infectious cause. Allergies generally cause clear, thin, watery mucus discharge.

Sneezing:

Sneezing is a more common symptom of allergies, especially when sneezing occurs two or three times in a row.

Time of year:

Colds are more common during the winter months, whereas allergies are more common in the spring through the fall, when trees, plants, and grasses are pollinating.

Presence of a fever:

Colds may be accompanied by a fever, but allergies are not usually associated with a fever.

5. What Does It Mean When a Product Is Labeled "Hypoallergenic"?

"Hypo" means "under" or "less than," so "hypoallergenic" means a product is less likely to trigger an allergic reaction.

Many products that we use every day, such as cleansers and soaps, deodorants, makeup, and even mouthwash, have ingredients that can irritate the skin or act as antigens (substances that trigger an allergic reaction). Exposure of the skin to these ingredients -- most often fragrances and chemicals used as preservatives -- can lead to a condition called contact dermatitis. Contact dermatitis appears as areas of redness, itching, and swelling on the skin, and sometimes as a rash or blisters.

Many manufacturers of cosmetics and cleaning supplies now market their products as "hypoallergenic," meaning the products do not contain ingredients that are known to cause irritation or allergic reactions. However, manufacturers are not required to prove the claim that their products are hypoallergenic, and there are currently no regulations or standards for manufacturers to follow.

Although choosing products that are hypoallergenic may help reduce the risk of contact dermatitis, no product can guarantee never to irritate the skin or produce an allergic reaction. It's always a good idea to test any new product before you use it, especially if you have had skin reactions in the past. To test it, simply put a sample of the product on your inner wrist or elbow and wait 24 hours to see if a reaction occurs.

6. Can Allergies Be Cured?

Allergies cannot be cured but the symptoms they cause can be treated and controlled. This may require making changes in your environment or behavior to avoid or reduce your exposure to certain allergens. Medication also may help relieve symptoms of an allergic reaction. Even with treatment, your body's immune system will continue to react when exposed to allergens. In some cases, however, children may outgrow their allergies, particularly those to food.

Immunotherapy, or allergy shots, is not a cure. Rather, the shots are a way to significantly lessen the symptoms caused by exposure to specific substances.

7. How Does Stress Affect Allergies?

Stress is your body's response to conflict or situations, both internal and external, that interfere with the normal balance in your life. Virtually all of the body's systems, including the digestive system, cardiovascular system, nervous system, and immune system, make adjustments in response to stress. When you are feeling anxious or stressed, your body releases numerous hormones and other chemicals, including histamine. Histamine is a powerful chemical that causes blood vessels to expand, which can lead to allergy-like symptoms.

Stress does not cause allergies but it can make an existing reaction worse by increasing the level of histamine in the bloodstream.

Reviewed by the doctors at The Cleveland Clinic Department of Pulmonary, Allergy and Critical Care Medicine.

Edited by Charlotte E. Grayson, MD, Feb. 2004, WebMD.

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