Ragweed plants are a common allergen. When a person breathes in ragweed pollen, their immune system may react as if it is an illness-causing substance, and they may experience allergy symptoms.
There are 17 types of ragweed that grow in the United States, typically releasing pollen between August and September.
Just one plant can release as many as 1 billion pollen grains, which create future ragweed plants and cause significant seasonal allergies.
In this article, learn about the symptoms and causes of ragweed allergies, as well as how to treat them and prevent symptoms in the future.
A ragweed allergy can cause many symptoms, including:
- itchy eyes, nose, and throat
- puffy eyes
- runny or stuffy nose
- difficulty sleeping
Ragweed allergy symptoms tend to occur in the late summer to early fall when ragweed pollen starts to spread.
Ragweed pollen usually peaks in mid-September. A person may notice their symptoms subside after that time.
In addition to these symptoms, a ragweed allergy may irritate the upper airways, leading to coughing and wheezing in someone who has asthma.
Ragweed tends to grow in rural areas in every state in the U.S. except Alaska. Common sites for ragweed to appear include riverbanks, roadsides, fields, and in vacant lots.
Ragweed seeds can stay dormant for 10 years or more and still grow into plants. Types of ragweed include:
- burweed marsh elder
- groundsel bush
- rabbit brush
Warm temperatures, winds, and humidity all help ragweed growth and transfer the pollen across large areas.
According to the Asthma and Allergy Foundation of America, pollen has been found 400 miles out at sea and 2 miles up in the air.
Ragweed is particularly resistant to herbicides, making it very difficult for farmers to kill when it is on their land.
Ragweed pollen counts tend to be at their highest when the temperatures are warmest during the day, usually between 10 a.m. and 3 p.m.
People with ragweed allergies are often also sensitive to certain foods. This is because some plants can contain pollen that is similar to ragweed. The condition is known as oral allergy syndrome.
Foods that may cause symptoms in a person with a ragweed allergy include:
- chamomile tea
- honey that contains pollen
- sunflower seeds
Some individuals may only experience mild symptoms, such as a runny nose or sneezing when eating these foods.
People can reduce the effects of oral allergy syndrome by cooking, peeling, or canning the fruits.
A ragweed allergy occurs if a person's immune system is sensitive to ragweed pollen.
When that person comes into contact with ragweed, their body will release immune system compounds that are called IgE. These compounds are meant to contain the pollen, but they also signal the release of inflammatory compounds called histamines.
The histamines go to the areas where the pollen was inhaled, often causing swelling and irritation in the nasal passages.
As a result, a person may experience sniffling, sneezing, and itching, usually around the nose and eyes.
Doctors can often diagnose a ragweed allergy based on a person's symptoms alone. They will usually ask when they first noticed symptoms and what makes them worse or better.
To confirm a ragweed allergy, a doctor can perform skin prick testing. This involves placing a small drop of diluted ragweed pollen on to the skin, then making a small scratch or prick.
If a person is allergic to ragweed, they will experience a mild reaction, including swelling, itching, or redness.
Another option to confirm an allergy is to have a blood test. A laboratory can test the blood for the presence of ragweed antibodies that indicate an allergy.
Unfortunately, there is no cure for a ragweed allergy. However, there are many treatments available to help manage the symptoms.
To reduce ragweed allergy symptoms, a person can:
- Check pollen counts daily and avoid going outside for an extended time when pollen counts are high.
- Change their clothes or take a shower after going outside during ragweed season.
- Keep windows closed when driving and at home. This can help to keep indoor areas pollen-free.
- Switch indoor air filters to certified asthma- and allergy-friendly HEPA filters.
- Take anti-allergy medications. These include cetirizine (Zyrtec), loratadine (Claritin), levocetirizine (Xyzal), and fexofenadine (Allegra). Ideally, a person can start to take these medications 1 to 2 weeks before seasonal allergy symptoms start.
- Use anti-itch eye drops or anti-inflammatory nasal sprays to reduce itching.
- Refrain from drying clothes on an outdoor line to avoid the clothes picking up pollen.
- Shampoo pets regularly if they go outdoors to prevent them from bringing pollen indoors.
- Wash bedding in warm, soapy water once a week to ensure pollen is not lingering on the sheets.
Doctors may recommend immunotherapy injections for more severe symptoms. These involve injecting increasingly larger amounts of ragweed pollen to reduce a person's symptoms.
Immunotherapy injections can help someone find relief from ragweed allergy symptoms for many years.
If a person has a fear of needles, they may be able to talk to doctors about tablets or drops to help reduce allergy symptoms.
Fortunately, ragweed allergy season is not year-round. While it may cause unpleasant symptoms for several weeks, symptoms will subside when ragweed plants stop producing pollen.
Until then, over-the-counter treatments and limiting time outdoors can help reduce the symptoms.