Seasonal allergies, also known as hay fever or seasonal allergic rhinitis, affect more than 35 million people nationwide. Allergy season generally lasts from February or March through October, depending on where you live. Allergy outbreaks usually happen when trees, flowering plants, grasses and weeds release pollen. Airborne mold spores also can bring on symptoms.

Pollen & Mold

Pollen are tiny, egg-shaped, powdery grains that help flowering plants reproduce. They usually are less than the width of a human hair.

Some people say they are allergic to roses or other brightly colored flowers, but these kinds of plants usually don't trigger hay fever. Bees and other insects carry the large, waxy pollen from plant to plant.

Instead, pollen particles from trees, grasses and weeds are usually the source of allergy outbreaks. Light and dry, these pollens are easily carried by the wind. During the late summer and early fall, ragweed is the most common cause of hay fever.

Mold spores float through the air like pollen. Outdoor mold spores often are released after the spring thaw, peaking in July in warmer states and October in colder states. Mold grows in soil, vegetation and rotting wood, to name a few places.

Signs & Symptoms

Symptoms include sneezing, congestion, a runny nose, postnasal drip, coughing and watery eyes, as well as itchy eyes, ears, nose and throat.

A person with allergies might also have "allergic shiners," dark circles under the eyes caused by increased blood flow near the sinuses. In children, watch for upward rubbing of the nose, known as an "allergic salute."

Airborne allergens also can trigger respiratory symptoms of asthma, such as difficulty breathing.

Hay Fever or Head Cold?

It's easy to mistake seasonal allergies for the common cold, but there are a few ways to tell the difference between the two.

Most colds clear up in 7-10 days, while allergy symptoms can last for weeks or months. If you're feeling achy and feverish, you probably have a cold. Hay fever usually produces a thin, watery, clear nasal discharge; a cold produces a thick, yellow or green discharge.

If your cold symptoms don't go away, see your healthcare provider. Allergists, doctors who specialize in allergic diseases, can conduct skin or blood tests to identify any allergies you might have.

Helpful Hints

Check pollen and mold counts. The National Allergy Bureau (NAB) collects pollen and mold counts from certified stations across the U.S. and reports them 3 times a week. Local and national weather reports generally carry these updates. Information about pollen and mold also is available on the NAB page of the American Academy of Allergy Asthma & Immunology Web site at www.aaaai.org.

Watch the weather. Rainy, cloudy or windless days mean lower distribution of pollen and mold spores. Hot, dry, windy weather spreads more pollen and mold spores and can make your allergy symptoms worse.

Close your windows and doors at night. This prevents pollen from entering your home while you sleep. Experts also suggest keeping your vehicle windows closed during travel.

Limit time outside. The early morning hours, especially between 5 a.m. and 10 a.m., are when the pollen count is normally high. Avoid being outside in dry and windy weather whenever you can.

Limit or avoid gardening and yard work. These activities can release pollen and mold spores. If you do work outside, wear sunglasses to protect your eyes and a face mask designed to stop pollen from entering your nose and mouth.

Kinds of Treatment

Antihistamines relieve sneezing, as well as itching in the nose and eyes, and reduce nasal swelling and drainage. However, some of these medicines have side effects that include sleepiness and loss of alertness and coordination.

Topical nasal steroids - anti-inflammatory medication that stops the allergic reaction - are sometimes used with antihistamines to treat moderate to severe allergies. Topical nasal steroids can have side effects, but they are generally safe when used at recommended doses.

Some doctors also might recommend using a decongestant, which helps drain nasal passages. Over-the-counter or prescription decongestant nose drops and sprays should not be used for more than a few days. When overused, these medications can cause more congestion and swelling of nasal passages.

Cromolyn sodium, a nasal spray, helps prevent allergic rhinitis from starting. The drug has few side effects and can help some people manage allergies.

A series of allergy shots, called immunotherapy, can help reduce symptoms over time. You receive injections of allergens to which you are sensitive under the skin at increasingly high levels. Research has shown about 85 percent of people with hay fever experience fewer symptoms and need less medication within 12 months of starting immunotherapy.

If your physician has prescribed medication, take it according to directions and recommended dosage. Also, be sure to consult your healthcare provider if you have questions about what type of allergy treatment is best for you.

Karin Lillis is regional editor at ADVANCE.