During the spring and fall most people with allergies experience the typical symptoms of sneezing, itchy eyes, and runny nose associated with "hayfever", medically termed seasonal allergic rhinitis. Other people with allergies may experience the same symptoms year round, they suffer from chronic allergies or perennial allergic rhinitis. The Major cause of seasonal allergies in the fall are weeds and molds. Ragweed, in particular, is one of the major causes of allergies in the United States. It is an allergen that is found in high concentrations across the country. Prior to colonial times, ragweeds were restricted to riverbanks, flood plains, and naturally eroded areas. They grew far apart and survived by their great ability to produce large quantities of small, buoyant pollen. As the country was explored and populated by settlers, these plants became ever more dominant, especially in the Northeast and Midwest.

Ragweed starts blooming as the days become shorter and the nights longer, but pollen stops forming as nights hours lengthen and the temperatures drop below 60 degrees Fahrenheit. Thus, in most areas, ragweed blooms for four to six weeks at nearly the same period each year (mid-August to the end of September, or until the first frost). In Texas ragweed may pollinate until late November. Each ragweed plant produces about one billion microscopic pollen grains during an average allergy season. Higher pollination rate is usually expected following mild winters when no freeze occurred. Ragweed pollens float in the air and may be carried out to sea as far as 300 or 400 miles. If a person is allergic to ragweed, it does not need to be growing in their back yard in order for symptoms to surface.

Molds also cause problems for allergy sufferers in the fall. Outdoor mold spores begin to appear after a spring thaw and reach their peak in either July, August, September, or October in the northern United States. Outside molds can be found all year long in the south. The most common molds are Alternaria, Cladosporium and Aspergillus species. Outdoors, molds can be found in soil, vegetation and rotting wood. Molds are propagated by their spores and can also be carried out hundred of miles away. Inside, molds are found in attics, basements, bathrooms, refrigerators and other food storage areas, garbage containers, carpets, and upholstery.

While the major causes of seasonal allergies in the fall are weeds and molds, spring allergies are mainly caused by tree and grass pollens. Trees start to pollinate early on in the spring while grass pollens may pollinate until June July. As for perennial allergies, indoor molds, dust mites and pet hair and dander are the main culprit for recurrent symptoms of sneezing, itchy eyes, and runny nose associated with "hayfever".

In order to determine if problems are caused by allergens (the substances which induce the allergic symptoms such as pollens, molds etc.), people should write down when symptoms have occurred in the past. Pollens allergens usually bother allergy sufferers during the fall or spring time. Mold spores can be stirred-up by a person working with any plant material, such as raking leaves or working in the garden. Recurrent allergic symptoms without a seasonal pattern may very likely be associated to perennial allergens such as molds, dust mites and pet allergens. Dust mite allergies are usually worse at night or early mornings.

If a person has a "cold" every fall when the weather cools, it may be allergies. A person who cannot rake leaves without feeling miserable, sneezing, or having a runny nose for hours afterwards, may have mold allergies. The child who is always sick at the beginning of the school year may not be "allergic to school", but rather to pollen in the air or allergens in classroom. The child who has nasal congestion or coughing after visiting a friend or his grandparents who have a dog or a cat, may suggest allergies. The tendency for recurrent symptoms and a specific seasonal or other associated pattern help your physician to determine whether your symptoms may be allergic.

Once allergies are suspected, it is important to discuss your problems with a trained allergist. An allergist is a physician who has had specific training in allergy as a subspecialty of internal medicine or pediatrics. He or she is trained to identify and solve the problems caused by allergies. The solution to the problem may be something as simple as avoidance of the allergen(s). If avoidance is not possible, as is often the case, there are number of effective medicines that may be tried.

If medications and avoidance are not effective in treating your allergies, allergy injections or immunotherpy is another effective alternative. Such injections have the advantage of potentially stopping the allergy-causing process, thereby eliminating the allergy rather than just treating the symptoms. Allergy injections have different benefits for different patients. Their usefulness for you can be determined by your allergist. If fall or spring brings sneezing, itching, and runny nose, it may be time to look at what allergens may be causing problems. Many effective solutions are available and should lead to more pleasant months for all allergy sufferers.