Skip to main content
Medically Approved

Why does my asthma flare up in the fall?

twitter share buttonfacebook share buttonlinkedin share buttonemail article button
If you have allergic asthma, autumn weather can bring as much suffering as spring. Prepare for the season with these tips.
Written by Emily Shiffer
Updated on September 19, 2022

Seasonal allergies can quickly take the joy out of a beautiful day. Spring is often thought of as allergy season. But fall is one of the worst times for allergies. And mid-September, in particular, takes the cake. Doctors often call the third week of September “asthma peak week.”

So why is fall the perfect storm for seasonal allergies? Mostly because of pollen.

“Weed pollen, especially ragweed, is one of the main causes of fall allergy symptoms,” says Clifford Bassett, MD. He’s an allergist who serves on the Asthma and Allergy Foundation of America Medical Scientific Council.

Human-caused climate change is creating longer and warmer growing seasons in North America. That’s according to a study published in 2021 in Proceedings of the National Academy of Sciences (PNAS). It’s based on research done from 1990 to 2018. This gives plants more time to grow and produce more pollen. So pollen concentrations are higher, and pollen seasons are longer.

“Pollen growing seasons have gotten 2 weeks longer on average. And more carbon dioxide emissions can create more potent pollen,” says Kenneth Mendez. He’s the president and CEO of the Asthma and Allergy Foundation of America (AAFA).

And a side effect of seasonal allergies is asthma. More than 25 million people in the U.S. have asthma. And allergic asthma is the most common type. It affects around 60% of people with asthma, according to the AAFA.

Here’s what happens with allergic asthma. Your immune system thinks the allergens are harmful. It responds to the threat by releasing a substance called immunoglobulin E (or IgE). This triggers inflammation and swelling in your lungs and can make it hard to breathe.

Struggling to breathe is a scary feeling. So read on to learn the most common fall triggers and how to prevent allergic reactions.

(Whether you use an inhaler or other medications to help with your asthma, we want to help you save on your prescriptions. Simply show this free discount card to your pharmacist — you could save up to 80%.)

The 2 biggest fall allergy triggers

Ragweed pollen

This pollen affects about 15% of Americans, according to the AAFA. Several types of ragweed grow in 49 states and have pollen so light that it can travel hundreds of miles. Depending on where you live in the U.S., ragweed season can start around July or August, peak in mid-September and last until November.

Ragweed can cause several asthma and allergy symptoms. They can include:

  • Runny nose
  • Nasal congestion
  • Sneezing
  • Red and watery eyes
  • Itchy nose, eyes, ears and mouth
  • Swelling around the eyes


The allergy symptoms from mold are very similar to ragweed and other allergens. “Mold spores may become airborne as we ease into autumn as decaying leaves and other vegetation fall to the ground,” says Dr. Bassett.

How to care for fall allergies

You can choose from many over-the-counter (OTC) and prescription medications to help treat fall allergies.

“OTC nasal corticosteroid sprays [such as Flonase or Nasacort®] are effective for allergic rhinitis (also known as hay fever). They’re especially good for nasal congestion and/or stuffiness,” says Dr. Bassett. Other medications that may help reduce symptoms include long-acting or non-sedating antihistamines, antihistamine nasal sprays, oral montelukast (Singulair) and cromolyn sodium nasal spray, he adds.

“A saline nasal rinse can help flush away excess nasal secretions and/or mucus, which can provide relief,” says Dr. Bassett. “This is helpful with cold symptoms as well.”

Antihistamines can also help. They block histamines, which are chemicals released by white blood cells when the immune system is triggered.

“If you need an antihistamine, choose one that is longer-acting and has fewer side effects than [traditional] diphenhydramine (Benadryl®),” adds Mendez.

If OTC options don’t ease your symptoms, you may need prescription inhalers or medications. These might include albuterol, ProAir® HFA, Symbicort, Flovent HFA and prednisolone.

Talk with your allergist before allergy season begins about which treatment is right for you. Some treatments work best if taken before symptoms start. Dr. Bassett recommends seeing an allergist for skin testing. It can help pinpoint a person’s seasonal or year-round triggers.

Pharmacists looking at medications.

Save up to 80% on your medications

Get prescriptions for as low as $4 with our free discount card, redeemable at over 64,000 pharmacies nationwide.

Get free card

How to prevent fall allergies

You can’t stop pollen and mold from getting into the air. But there are ways to protect yourself, according to the asthma & allergy friendly® Certification Program. This program is jointly run by the AAFA and Allergy Standards Limited (ASL).

Keep windows and doors closed

Although a nice cool breeze on a crisp fall day may be refreshing, it could be trouble for your allergies. Keeping your windows closed will prevent pollen from coming into your home. 

Change and wash your clothes after spending time outdoors

Pollen can stick to any and all surfaces. So as soon as you come indoors, remove your clothes and throw them in the washer to help reduce exposure.

Cover your hair when you go outside or wash it at night to remove pollen

Hair is the perfect pollen trap. To keep pollen from sticking, cover your hair with a scarf or hat. And wash it to rinse out all the pollen.

Protect your eyes, nose and mouth

Wear sunglasses and a mask while outside to keep pollen from getting in your eyes and prevent you from inhaling pollen.

Stay on top of yard work

Maintaining your yard can reduce the amount of mold outside your home. Cleaning up fall leaves and yard debris as soon as possible prevents more mold from growing. While raking, protect yourself by wearing a mask (an N95 mask is recommended for mold). 

Reduce moisture in the bathroom and kitchen

This can help prevent mold from growing in these spaces. You can do that by:

  • Not running the shower for a long time before you get in
  • Using dehumidifiers to keep humidity below 45%
  • Limiting the number of houseplants you have
  • Fixing all leaks as soon as possible
  • Cleaning up mold right away

Talk with your doctor

If you’re struggling with severe fall allergies, don’t be afraid to reach out to your doctor.

“Seasonal allergy symptoms can be similar to a cold, the flu or other respiratory infections,” says Dr. Bassett. “The respiratory symptom chart [available in English and Spanish] developed by the AAFA can help you understand the different symptoms you may be experiencing.”

No matter how you manage your allergies, Optum Perks wants to help you save at the pharmacy. Here’s how it works.

Additional sources
Climate change and pollen levels: Proceedings of the National Academy of Sciences (2021). “Anthropogenic climate change is worsening North American pollen seasons”
Statistics on allergies in the U.S.: Asthma and Allergy Foundation of America
Ragweed pollen allergies: Asthma and Allergy Foundation of America
Allergy certification program: asthma & allergy friendly®
Respiratory symptoms chart: Asthma and Allergy Foundation of America