Kathi Valeii is a freelance writer covering the intersections of health, parenting, and social justice.

Daniel More, MD, is a board-certified allergist and clinical immunologist with a background in internal medicine.

Fall allergies occur in the autumn months from September through December. They may be a combination of indoor and outdoor allergies. Since they occur during months when illnesses are more common, people sometimes have difficulty discerning whether they are sick or experiencing allergy symptoms.

This article explains symptoms, causes, and treatment options for fall allergies.

More than 50 million Americans experience various allergies every year.

Fall allergy symptoms occur when your body produces excessive histamine, a chemical that protects your body from foreign substances. With allergies, the immune system misinterprets allergens as harmful and attacks them. 

This immune reaction results in many symptoms that can range from mild to severe, including:

Allergic asthma occurs when allergens prompt an asthma attack. When this happens, you may experience wheezing, coughing, and have trouble catching your breath. These responses can be life-threatening if not controlled, so if you have allergic asthma, be sure to work with a healthcare provider to manage it.

Fall allergies may be caused by both indoor and outdoor allergens. 

Dust allergies result from an allergy to dust mites, microscopic organisms that live in bedding, upholstery, carpeting, and other soft surfaces. Since dust mites thrive indoors, dust mite allergies occur year-round.

While you can’t eliminate dust mites, you can reduce your exposure to them by:

Pet dander is a common source of year-round allergies for many people. Dander isn't an allergy to pet hair, as some mistakenly believe, but rather a pet's skin. However, pet allergies may be exacerbated by shedding breeds because pet hair can carry the dander.

To reduce your pet allergy symptoms, try the following:

Mold is an indoor and outdoor allergen. Indoors, it grows in moist places where water gathers or condenses, like kitchens, bathrooms, and basements. Outdoors, you’ll find it in leaf piles, rotting logs, and compost piles. 

You can reduce your exposure to mold by:

Pollen is responsible for many seasonal allergies during the spring, summer, and fall months. Depending on the season, different pollens may be culprits for your allergy symptoms. For example, the most common culprit in the spring is trees, late spring to mid-summer is grass pollen, and in the late summer, it’s weed pollen.

In the fall, the most common pollen allergy is ragweed.

Pollen is a powdery substance produced by seeding plants. This substance is released into the air so that birds and insects can spread it to fertilize plants. 

Pollen allergies are also known as outdoor allergies, environmental allergies, and hay fever. These allergies can be frustrating because it’s challenging to mitigate exposure without staying exclusively indoors. However, there are some things you can try, including:

COVID-19 and allergies share many symptoms, including nasal congestion, runny nose, cough, sore throat, headache, and fatigue. However, there are some ways to tell them apart.

Loss of taste or smell

Does not produce a fever

Usually no loss of taste or smell, but could be dulled due to congestion

When in doubt, it doesn’t hurt to take a COVID-19 test to be sure.

While there is no cure for allergies, there are many ways to manage symptoms.

Nasal sprays are the most effective line of treatment for nasal allergies. Steroid nasal sprays work by reducing inflammation in your sinuses. Common steroid nasal sprays include Nasonex (prescription) and Flonase (available over-the-counter). 

In addition, saline nasal sprays are a saltwater solution that can help relieve dryness and congestion. 

Antihistamines are medications that block histamine, the chemical responsible for your allergy symptoms. Antihistamines effectively treat allergy symptoms, including itchy and watery eyes, and sneezing. 

These drugs are available over-the-counter (OTC) and by prescription. A common side effect of older antihistamines (known as first-generation medications) was sleepiness and sedation. Benadryl (diphenhydramine ) is an example of a first-generation drug that causes drowsiness. 

However, second-generation medications, like Claritin (loratadine ) and Zyrtec (cetirizine ), do not carry this same side effect. As a result, many people prefer them for this reason. 

Decongestants work by shrinking your blood vessels to help ease congestion. Sudafed and Afrin are examples of OTC decongestants. 

While they are effective, they are intended for short-term use because longer-term use can result in dependence and rebound congestion (nasal congestion that worsens from dependence on decongestant medication).

People often use a combination of medication and home remedies to treat their allergy symptoms. However, limiting exposure to allergens is the best way to manage allergies. 

Keeping indoor humidity low can reduce allergens like dust mites and mold. Try keeping a dehumidifier in damp areas, like the basement, for the best effect. 

The vents in your home are an often overlooked spot that can harbor lots of dust. Consider having your ducts cleaned on a consistent schedule. In addition, remember to replace your furnace filter every few months.

If you have pollen allergies, keep an eye on pollen counts and stay indoors during peak pollen times. If this isn’t feasible, mitigate in other ways like keeping windows closed and showering and washing your clothes after you’ve been outside. 

Fall allergies occur in September through December. Allergy symptoms include sneezing, coughing, congestion, a runny nose, and more. Fall allergens include dust, mold, pet dander, and pollen. Antihistamines and nasal sprays are some of the over-the-counter medications that are used to treat fall allergies, along with home remedies, such as using a dehumidifier and regularly cleaning out vents at home.

If you have fall allergies, you may benefit from a layered mitigation strategy that includes limiting exposure to allergens, medication, and at-home remedies. In addition, allergy testing can help you pinpoint your allergens, which can help you know which things to avoid.

Fall allergies begin late summer into early fall, when fall plants, like ragweed, begin to release pollen.

Fall pollen allergies usually subside around the first frost. So, when you can expect to find relief from fall allergies depends on the climate where you live.

Depending on the climate where you live, fall pollen allergies may last a few months.

The most common fall pollen allergy is ragweed. Mold, which you can find indoors and outdoors in the fall, is also a common fall allergy.

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Asthma and Allergy Foundation of America. Allergy facts and figures.

American College of Allergy, Asthma, and Immunology. Allergy symptoms.

American Lung Association. Dust and dust mites. 

Asthma and Allergy Foundation of America. Mold allergy.

American College of Allergy, Asthma, and Immunology. Environmental allergy avoidance.

National Institutes of Health: News in Health. Is it flu, COVID-19, allergies, or a cold? 

Juel-Berg N, Darling P, Bolvig J, et al. Intranasal corticosteroids compared with oral antihistamines in allergic rhinitis: a systematic review and meta-analysis. Am J Rhinol Allergy. 2017;31(1):19–28. doi:10.2500/ajra.2016.30.4397

American College of Allergy, Asthma, and Immunology. Air filters: overview.

United States Environmental Protection Agency. Climate change indicators: ragweed pollen season.

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