The Horror of Ragweed and Seasonal Allergic Rhinitis

What is seasonal allergic rhinitis? If you do not know or have no reason to, consider yourself very, very lucky because in the United States alone, approximately 20% of the population suffers from what we commonly call seasonal allergies or hay fever. Rhinitis, meaning the inflammation of the lining of the nose, can cause severe discomfort and significantly affect one’s ability to function day to day. Millions of school and work days are lost to the disease; annual medical costs to treat allergic rhinitis exceed over four billion dollars per year (2). Why and how do we become the victims of our immune system as the seasons change? Seasonal allergies are a problem, a big problem, that we must understand and treat in order to best preserve our health and wellbeing.

One of the most disappointing aspects of allergies, I find, is that we are not born with allergies, rather we develop them over time as our bodies and immune system become exposed to allergens in the environment, such as pollens, dust, animal dander and other airborne substances. While many people develop allergies at a young age, a person may develop allergies at any time of his or her life; two-thirds of patients experiencing allergic rhinitis develop the illness before the age of thirty (2). I, for example, did not develop allergies until the age of eighteen, and previous to that point had never known what it was to be debilitated by a relatively harmless substance such as ragweed. I still a newly coping patient of allergies and have not quite come to terms with my condition: what is happening to my body, what causes a person to develop allergies? Why me? Why is my immune system unnecessarily attacking these allergens and thus significantly impairing my ability to work, study and live? Although we do not understand why we are allergic to certain substances in our environment and what evolutionary/ biological purpose allergies serve, if any, we do know that allergies are a highly common, highly hereditary trait. If your parents experience allergic rhinitis, your chances of developing allergies reach up to 60% (3).

Allergic rhinitis can be seasonal or perennial. Perennial allergic rhinitis is a result of sensitivity to house dust mites, mold spores, animal dander, and other substances present year round that provoke chronic symptoms of allergies, such as sneezing, runny nose, itchy eyes, congestion and coughing. Seasonal allergic rhinitis can begin in early spring and last until the first freeze of fall; ragweed pollen is the most common trigger of seasonal fall allergies (4). Ragweed is a yellow flowering weed that flourishes during hot and dry spells of the summer. It releases copious amounts of pollen, which can only be suppressed by humidity and freezing temperatures that kill the weeds and prevent the pollen from being spread. This weed is rampant all throughout the United States; the peek of pollen dispersal usually is during mid-September. When we breathe in this pollen is when problems begin to occur and we experience seasonal allergic rhinitis (5).

We have allergic reactions to ragweed pollen because when we breathe it in, our body and immune system identifies it as a foreign invasion that must be destroyed. The symptoms we experience such as the runny nose and sneezing are the body’s attempt to expel the foreign substance and are triggered by antibodies produced by plasma cells located under the mucus membranes. The development of antibodies occurs after the body has become sensitized to the offending allergen. Immunoglobulin E, IgE, is the antibody most commonly associated with allergic reactions; the IgE attaches itself to the mast cells that reside in the tissue that lines our nasal passages, bronchial tubes, gastrointestinal tract and even in our skin. The IgE also infiltrates our basophils, cells that circulate through our blood stream. When the pollen enters the body, the antibodies attack it by sending signals to the mast and basophil cells, which then release a deluge of chemicals such as histamine and heparin. These chemicals cause surrounding tissue to inflame, mucous production becomes bountiful, and then we itch all over as another reminder from our body to stay away from the offending allergen. Some people experience a delayed response in allergic reactions because the chemicals released will attract other immune system cells such as lymphocytes, who then in turn release other chemicals that can cause tissue damage up to 24 hours following exposure to the allergen (3).

One of the injustices of seasonal allergies is that it is very hard to avoid contact with airborne allergens. Pollen and dust are virtually everywhere and leave us little room to hide. Wind can carry pollen grains hundreds of miles before we inhale it, or it can come from the backyard. Preventing seasonal allergies, or rather its corresponding horrendous symptoms, requires a multifaceted strategy, combining medication (such as antihistamines), education and avoidance of allergens. Educating yourself about how to best treat and prevent your specific allergies can allow you to lead a life less disturbed by the discomforts of allergic reactions.

Sources:
1) “Allergies and Their Treatments” by Samantha Manewitz, a fall 2001 Biology 103 web paper (/biology/b103/f01/web2/manewitz.html)
2) Health Encyclopedia- Diseases and Conditions: Allergic Rhinitis, an article online health and medicine encyclopedia (http://www.healthscout.com/ency/68/208/main.html)
3) “Ragweed Pollen Allergy,“ helpful information about seasonal allergies, treatments, and seasonal rhinitis. (http://allergies.about.com/od/ragweed/)
4) “How Did I become Allergic, “ A complete allergy guide from the National Jewish Medical Research Center (http://www.njc.org/disease-info/diseases/allergy/about/causes/become.aspx)
5) “Something to Sneeze at: Seasonal Allergic Rhinitis, “ A great article from CBC News (http://www.cbc.ca/news/background/health/hayfever.html)