Though the flowers are no longer blooming and the air has turned crisp and cool, many allergy sufferers get no reprieve during the fall months. The allergy triggers might be slightly different, but they can be just as misery-inducing as the flower pollen that fills the air in the spring and summer.

What Causes Fall Allergies?

Male plants release tiny cells called pollen into the air in order to reproduce. When these pollen or other allergy triggers get into the noses of certain people, their immune system mistakenly sees them as foreign invaders and releases antibodies -- substances that normally identify and go after bacteria, viruses, and other illness-causing organisms. The antibodies attack the allergens, which leads to the release of chemicals called histamines into the blood. Histamines trigger the runny nose, itchy eyes, and other symptoms of allergies.

During the fall season, ragweed is the biggest allergy trigger. Though the yellow-flowering weed typically begins pollinating in August, it can linger well into the fall months. About three-quarters of people who are allergic to spring pollen-producing plants are also allergic to ragweed. Ragweed pollen can travel for hundreds of miles on the wind, so even if it doesn't grow where you live, it can still make you miserable if you're allergic to it.

Mold is another culprit, because its spores can easily get airborne. Mold thrives in damp areas, both indoors and outdoors. The piles of damp leaves that line yards and streets in the fall are breeding grounds for mold, as are damp basements and bathrooms at home.

Dust mites -- microscopic, spider-like insects -- are yet another common indoor allergen. They are most prevalent during the humid summer months, but can get stirred into the air the first time you turn on your furnace in the fall. From the air, dust mites can make their way into your nose, triggering sneezes, wheezes, and runny noses.

Children and Fall Allergies

For children, the start of a new school year can also mean the beginning of fall allergy symptoms. Dust mites and mold both flourish in schools. Add to that chalk dust, which can get airborne with the bang of an eraser and trigger wheezing in children with asthma. Considering all of these potential allergens, it's not surprising that researchers have noted a sharp spike in asthma symptoms among children during late September and early October.

Food allergies are also an issue during the fall. Going back to school means sharing a cafeteria with children who are eating peanut butter, eggs, milk, and other foods that can be irritating --even life threatening -- to kids with allergies. Even Halloween becomes more trick than treat for kids who are allergic to the nuts and other candy ingredients.

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