Running from Ragweed: How to Cope with Fall Allergies

By: Christine Haran
Last Reviewed on: April 25, 2005
Some people find themselves retreating indoors in late August, not because of the heat and humidity but because of their allergies. In the Northeast, South and Midwest, ragweed begins blooming in mid-August and continues until late October and sometimes longer. This leaves ragweed-allergy sufferers unable to enjoy the fall season.

A Hardy Weed
Ragweed, like other fall allergens such as sage, mugwort, and rabbit brush, usually grows in undeveloped areas such as fields, roadsides, and abandoned lots. But because billions of pollen grains from a single ragweed plant can travel through the air for up to 400 miles, ragweed pollen is found in urban, suburban and rural settings.

"Ragweed is incredibly hardy." says Dr. Christopher Randolph, an associate professor of allergy and immunology at Yale University School of Medicine and a spokesperson for the American Academy of Allergy, Asthma and Immunology (AAAAI). "It can be borne for miles into the air and is found at sea and on every continent."

Sufferers? Symptoms
When someone is allergic to ragweed, the immune system treats the plant?s pollen as a foreign invader. First, white blood cells produce IgE antibodies that specifically target ragweed pollen. These antibodies attach themselves to mast cells, which exist in large numbers in the nose, eyes, lungs and digestive tract. When pollen is inhaled, these mast cells release histamine and other chemicals that cause the misery of hay fever: sneezing, an itchy, runny nose, and itchy, red eyes. Such symptoms can lead to fatigue, trouble concentrating, and missed days of work or school.


Compared with certain year-round allergens, such as dog and cat dander, seasonal allergens like ragweed may be less likely to cause asthma symptoms. "Animal allergens, for example, are very small, which means they can get deep in the airway and trigger asthma." Randolph explains. "Pollens don?t get much below the windpipe, so they cause nasal symptoms."

Still, worsening nasal allergies can generate asthma attacks and can be an important element in asthma treatment.

Some people with ragweed allergies may notice that they develop itchiness around their mouth and in their throat when they eat melons and bananas. This is due to a protein in these fresh fruits that is similar to the one in ragweed. Luckily, this cannot lead to a life-threatening allergic reaction known as anaphylaxis.

While symptoms are often used to diagnose ragweed allergy in the primary care doctor?s office, a more accurate approach is a skin sensitivity test performed by a board-certified allergist. In these tests, the skin is pricked with an extract of ragweed pollen. If a person has a ragweed allergy, the skin will become red and swollen.

Pollen Exposure
While the peak pollen times are between 10 a.m. and 4 p.m., pollen counts vary from day to day. Hot, dry and windy days are often the worst for pollen and, in general, pollen counts over 100 are considered high. According to Randolph, pollen counts can be useful, if not completely precise. "Most pollen counts reflect what?s going on over a 24-hour period, not what?s going on right now, so use it as a guide." he says.

To minimize exposure to ragweed and other pollens, the AAAAI recommends that allergy sufferers stay indoors with the windows closed and the air conditioning running as much as possible. After spending time outdoors, it?s a good idea to shower to remove pollen that?s collected on your hair and skin.

Easing Allergies If avoidance just isn?t doing the trick, people with ragweed allergies may need medication. Nasal sprays, including nasal antihistamines and nasal inhaled corticosteroids can reduce inflammation and ease symptoms. Randolph cautions that certain over-the-counter decongestant nasal sprays can have a "rebound effect" because they do not block histamine, but rather constrict the blood vessels in the nose. After about a week, the nervous system rebounds and dilates the blood vessels, causing increased blood flow and congestion.

Likewise, patients with eye symptoms, also known as allergic conjunctivitis, should seek out prescription eye drops that block histamine or inhibit mast cells, rather than over-the-counter eye drops that just constrict the blood vessels to reduce redness. Randolph recommends refrigerating eye drops for extra relief. Other ways to ease itchy, red eyes include applying cold compresses and using artificial tears to wash away allergens from the eyes.


Over-the-counter and prescription oral antihistamines and decongestants treat multiple symptoms, though Randolph warns that non-sedating antihistamines are safest. People with chronic allergy symptoms who need antihistamines on a regular basis may be candidates for immunotherapy, or allergy shots. This treatment, which is prescribed by an allergist/immunologist, seeks to build the immune system?s tolerance to an allergen. Patients receive a series of injections that contain a small amount of the offending substance?usually weekly at first, and then monthly; the therapy may continue for three to five years.

So those with ragweed allergies who are just trying to wait out the end of the season can take heart: With avoidance and treatment, you don?t have to sniffle your way from late summer to Thanksgiving.