In the late summer, about 15% of Americans have symptoms from an allergy to ragweed pollen.1 The symptoms can make life miserable for those with allergies. This allergy can also cause asthma symptoms for people with allergic asthma.
You may feel uncomfortable when ragweed plants release pollen into the air. Your symptoms may continue until the first frost kills the plant. Depending on your location, ragweed season may last six to 10 weeks. In most areas in the U.S., it peaks in mid-September.
Ragweed is a weed that grows throughout the United States, especially in the Eastern and Midwestern states. Each plant lives only one season. But that one plant can produce up to 1 billion pollen grains.
When mid-August nights grow longer, ragweed flowers mature and release pollen. Warm weather, humidity and breezes after sunrise help release the pollen. The pollen then travels through the air to another plant to fertilize the seed so a new plant can grow next year.
Ragweed usually grows in rural areas. Near the plants, the pollen counts are highest right after dawn. Rain and morning temperatures below 50 degrees Fahrenheit slow down the release of pollen.
Ragweed pollen can travel far. It has been found in the air 400 miles out to sea and two miles up in the atmosphere. But most falls close to its source.
Turf grasses and other perennial plants easily overgrow ragweed. But where streams of water, farming or chemicals upset the soil – like salting roads in the winter – ragweed will grow. It is often found along roadsides, riverbanks, in vacant lots and fields. Dormant seeds that live in the soil for decades may grow when the conditions are right.
The job of your immune system is to find foreign substances, like viruses and bacteria, and get rid of them. This response normally protects us from harmful diseases. People with allergies have immune systems that react when they come in contact with allergens. When you are allergic to ragweed pollen and inhale it from the air, rhinitis (hay fever) symptoms show up.
Seventeen types of ragweed grow in North America. Ragweed also belongs to a larger family of plants that can spread pollen by wind. These plants can also cause symptoms.
Members of this plant family include:
Some family members spread their pollen by insects instead of by wind. They cause fewer allergic reactions. But sniffing these plants can cause symptoms.
Seventy-five percent of people who are allergic to pollen are also allergic to ragweed. If you have allergies to one type of pollen, you tend to develop allergies to other types of pollen as well.
If you have a ragweed allergy, you may also get symptoms when you eat these foods:
This is called oral allergy syndrome (OAS). OAS occurs because your immune system confuses ragweed pollen with certain foods. Common OAS symptoms include itchy mouth, throat, tongue or face.
Rhinitis symptoms often include:
If you think you are allergic to ragweed pollen, see a board-certified allergist. They will ask you about your medical history, do a physical exam and allergy testing. They may do a skin prick test to confirm your allergy.
For prick/scratch testing, the doctor or nurse places a small drop containing ragweed pollen on your skin. They will then lightly prick or scratch your skin with a needle through the drop. If you are sensitive to ragweed, you will develop redness, swelling and itching at the test site within 15 minutes. Sometimes your doctor may take a blood test to see if you have the antibody to ragweed.
There is no cure for a ragweed pollen allergy. But there are ways to treat and manage it.
Track the pollen count for your area. The news media often reports the count for your area, especially when pollen is high. You also can get your area’s pollen counts from the National Allergy Bureau.
Stay indoors in central air conditioning when the pollen count is high. Get a CERTIFIED asthma & allergy friendly® air filter for your air conditioner. If you do spend time outside, try to go out before 10 a.m. and after 3 p.m. Ragweed pollen peaks in the middle of the day.
Prevent pollen from being tracked into your home. If you spend a lot of time outside during peak pollen time:
You might even consider moving to get away from ragweed. This will often help you feel better for a short time. But you can develop allergies to plants in your new location in a few years. And ragweed is found in every state except Alaska. A well-thought out treatment plan is a better way to live with your allergies.
Take anti-inflammatory or antihistamine medicines, and start treatment in the summer. Many over-the-counter medicines work well to control pollen allergy symptoms. They can also help eye, nose and asthma symptoms. Many newer antihistamines don’t cause as much drowsiness as older ones.
Anti-inflammatory and antihistamine nose sprays also help and have few side effects. You can also find eye drops for eye symptoms. Leukotriene inhibitors can help by blocking chemicals your body releases when you have an allergic reaction.
For long-term relief, see an allergist about immunotherapy. This type of treatment can reduce the allergic response to specific allergens. There are two types: allergy shots and sublingual immunotherapy (SLIT).
Allergy shots involve giving injections of allergens in an increasing dose over time. They relieve symptoms for most people and can last for years to decades.
With SLIT, you take a small dose of an allergen under your tongue. You also gradually become more sensitive.
With the right treatment plan, you should see major improvements in your symptoms.
1. Salo, P.M., S.J. Arbes, Jr., R. Jaramillo, A. Calatroni, C.H. Weir, M.L. Sever, J.A. Hoppin, K.M. Rose, A.H. Liu, P.J. Gergen, H.E. Mitchell, and D.C. Zeldin. 2014. Prevalence of allergic sensitization in the United States: Results from the National Health and Nutrition Examination Survey (NHANES) 2005–2006. J. Allergy Clin. Immun. 134(2):350–359.
Medical Review August 2019.