What are fall allergies?

Couple laughing at the joyful whirl of fall leaves tossed up in the air by a gust of wind

Late August to November is one of the busiest times of the allergy year. Weed pollen and mold spores fill the air outdoors. They’re the typical fall allergies. But dust mites and pets (not officially seasonal) can make allergic rhinitis symptoms flare up too as we spend more time indoors.

You’ve got an itchy nose and watery eyes. And there it is, another sneeze. Summer’s over. So it could be fall allergies. But your hay fever symptoms might also be a cold, which is another type of rhinitis. Being in closer proximity to people again and kids going back to school makes this a season for sharing cold viruses.

Confusing, isn’t it? That’s why we’ve written this article about the causes and symptoms of fall allergies. You'll also find out how to get an allergy diagnosis and what to do if you are allergic to something, from avoiding your trigger to treatment options.

What allergies flare up in the fall?

Seasonal allergies follow the life cycle of particular plants. That is, when they release pollen or spores to reproduce. Perennial allergies can cause symptoms all year round but may also wax and wane according to what’s happening in your life. Read on to find out more.

Allergy or back-to-school cold?

Man in the park blowing his nose into a white handkerchief – does he have a cold or an allergy?

Fall allergies: Seasonal triggers

In the fall months, weed pollen counts are high (trees mainly release pollen in the spring and grass in summer). Here are some common types of weed pollen that can cause hay fever symptoms:

  • Ragweed
  • Burning bush
  • Cocklebur
  • Lamb’s-quarters
  • Mugwort
  • Pigweed
  • Russian thistle
  • Sagebrush
  • Tumbleweed

Ragweed is considered to be the main culprit behind fall allergies. Its pollen grains are tiny and very light, so the wind can carry them hundreds of miles from the plant. This means people with ragweed allergy may get symptoms and have no idea why.

From late summer into the early fall months, outdoor mold species release their spores. Go kicking through piles of fallen leaves and you could end up sneezing.

Year-round triggers with a seasonal peak

The allergies in this article are respiratory. It’s breathing in airborne particles which triggers your allergic symptoms. As well as pollen and spores outdoors, there are indoor allergens in household dust that can be more troublesome at this time of year. Sitting on the sofa to watch the fall season of your favorite TV show can make dust fly, though you may not realize it. Snuggling up under the duvet for longer can increase your exposure to certain allergens too.

Dust mites thrive in warm, humid environments. The tiny creatures are commonly found in bedding, upholstered furniture and carpeting. Exposure to dust mite waste can cause allergy symptoms. Our cats and dogs also add to household dust. Pet dander is made up of tiny flecks of dead skin and other allergens. It can remain suspended in the air for long periods of time and sticks to fabrics, bedding and furniture. Allergenic indoor mold spores can be a component of household dust too.

Why do my allergies feel worse in the fall?

Some people have more than one allergy but only have mild symptoms until they’re exposed to all their triggers at once. Maybe you’re allergic to dust mites and have the occasional stuffy nose in the morning for most of the year. Then along comes weed pollen season. Now your immune system is reacting to the cumulative allergen levels of both dust mites and weed pollen.

Fall allergies…or a cold?

Seasonal allergies can be tricky to diagnose. Many people assume they have a cold when they start getting a runny nose and sneezing.

But colds tend to come on gradually and last for several days (or longer). Allergic rhinitis may appear suddenly and lingers as long as you’re exposed to the allergen, which could be weeks or months. Also, colds usually involve other symptoms like fever and body aches, which are not typical with fall allergies.

A doctor explaining a patient about dust mites allergy treatment in pink

Dust mite allergy treatment

Symptoms of fall allergies

It can vary from person to person but these are the common symptoms of perennial and seasonal allergic rhinitis:

  • Stuffy nose (nasal congestion)
  • Runny nose, usually with clear fluid
  • Sneezing
  • Itchy nose
  • Itchy, red or watery eyes
  • Post-nasal drip (the feeling of mucus moving down the back of your throat)
  • Cough
  • Tight chest or wheezing
  • Sinus inflammation/pain

As well as these allergy symptoms, dust mites can give you an itchy rash.

How to tell if it could be fall allergies

Your healthcare provider will help you figure it out. They may suggest you have one or more allergy tests to check what you could be sensitized to. An account of your symptoms and medical history will help make the diagnosis. Also whether allergy runs in the family.

Managing your fall allergies

Allergies can be frustrating to deal with, until you know how. The typical approach is to avoid your allergen but to be ready to relieve any symptoms if you are exposed to it. Long-term treatment may also be an option.

Tips on how to avoid your allergen

Avoiding your allergen is the first step to managing symptoms. That could be checking the pollen count and shutting windows on pollen-y days. Or keeping humidity down, which dust mites won’t like. Or putting a HEPA filter into your vacuum and cleaning your home even more rigorously than you do already.

You’ll find more advice in our seasonal allergies article.

Young woman holding a small dog that might be causing her allergy symptoms
Allergy checker
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Short-term relief for fall allergy symptoms

Saline nasal spray or eye drops from the pharmacy are a drug-free soother and help flush out allergens. A saline nasal spray can also make antihistamine, a common allergy medication, more effective. Corticosteroids are an alternative symptom-reliever. Taking allergy medicine before you expect your fall allergies to start could mean milder symptoms when the season starts.

Meanwhile nasal decongestants unblock a stuffy nose. But you should only use your nasal spray for a few days even if the symptoms of fall allergies persist. After that, you may find it doesn’t work as effectively. Overuse of nasal decongestants can cause swelling, which is known as the rebound effect.

Long-term treatment for fall allergies

Allergy immunotherapy aims to influence the way your body reacts to your allergens so that you eventually have fewer symptoms. It’s also known as desensitization.

The treatment exposes you to tiny doses of your trigger over a period of time, usually available as a series of injections or tablets. Ask your healthcare provider if it could be right for you. We can also help you find an allergy specialist, if you need one.


Weed pollen and mold spores are the big allergy triggers in the fall. But perennial allergies can flare up at this time of year too, including pet dander and dust mites. But there are things you can do to tackle your fall allergies and live the life you want to. Get expert advice on how to avoid your allergen, and how to ease hay fever symptoms when you can’t. Drug-free relief, short-term allergy medicines and immunotherapy may all be options.

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Last medically reviewed on 8/11/2022