Seasonal vs. Year-Round Allergies: Differences, Symptoms, and Relief Tips

Seasonal Allergies

Seasonal allergies are exactly what the name describes — allergies that change based on the season. These are often divided into spring, summer, fall, and winter allergies.

While the different types of allergens change throughout the year, seasonal allergy symptoms stay the same, such as:¹

• Runny nose

• Itchy, watery eyes

• Congestion or sinus pressure

• Sneezing

• Itchy throat

Seasonal allergies are different from year-round allergies because they tend to be caused by outdoor allergens like pollen, insects, and mold. On the other hand, year-round allergies are always lurking, but tend to flare up in the winter when we spend more time indoors.¹

Spring Allergies: Tree and Grass Pollens

After long, cold winters, many plants begin growing and flowering during the spring. This can lead to high pollen counts in the air, especially from trees and grasses. Pollen from these plants is typically light and dry and travels easily with the wind. With it swirling around in the air, allergies can be in full swing.²

In the United States, tree pollen is the first allergen to appear each year and is responsible for most allergy symptoms in the spring. For most states, trees produce pollen from March through May — in warmer climates in the South, some trees begin producing pollen in January and continue to do so throughout the year,² causing perennial allergies.

As late spring continues into early summer, grasses also begin releasing pollen that can be irritating to those with spring allergies. The same trend in the South for trees also applies to grasses — they may release pollen for many months throughout the year, triggering allergies for some people over multiple seasons.²

If you’re looking for tips to help manage spring allergies from tree and grass pollens, read our guide to outdoor allergies here.

Summer Allergies: Insects, Mugwort, and Ragweed

Weeds — like ragweed and mugwort — produce pollen during the late summer into early fall. Ragweed is found in 49 of the 50 states and can travel for hundreds of miles with wind, making it difficult to avoid this allergen. Some tree and grass pollens can also continue from the spring into summer, exacerbating allergies for those who are allergic.²

Summer allergies bring more pollen, along with pesky insects that love to bite. Insects like mosquitos, bees, wasps, and hornets are most active during the summer months. These stinging and biting bugs can cause mild reactions in some people and more severe allergic reactions in others. They tend to nest in the ground, walls, bushes, and trees, so be sure to keep an eye out for them in warmer months.^3,4

Fall Allergies: Ragweed Pollen and Outdoor Mold

Even as the weather cools down, pollen from weeds can still trigger your fall allergies. Ragweed begins producing pollen in the summer, but it tends to peak in the early fall.⁵

Damp weather can also bring about outdoor mold, which can trigger allergies in some people. Mold likes to grow on damp surfaces, such as rotting logs and wet piles of leaves that form after falling from trees. Mold spores — which are similar to seeds — can also spread through the air in dry, windy climates. These spores often trigger allergy symptoms and can survive in cold weather, so you may experience mold allergy symptoms until late fall or early winter.⁶

Winter Allergies: Indoor Allergens Thrive

Pollen levels are usually low once the weather turns cold, but staying warm inside can still expose you to indoor allergens like dust mites, mold/mildew, or pet dander. Yes, it is possible to experience allergies in the winter! To help the allergens in your home bite the dust, try these tips:

• Wipe down surfaces regularly with dust rags and damp mops to clean away dust and pet dander

• Wash your bedding in hot water and dry in a hot dryer

• Leave your shoes at the door when coming inside to avoid bringing in dust

For more tips on how to fight indoor allergies, read here.

Year-Round and Indoor Allergies

Year-round allergies can occur at any time, but they’re most common in the winter when we stay indoors. Allergens like dust, pet dander, and mold/mildew can trigger allergic reactions at all times of the year, especially if measures aren’t taken.⁷ Some signs and common symptoms of year-round or indoor allergies include:⁸

• Itchy eyes, nose, mouth, and throat

• Watery eyes

• Nasal congestion

• Sneezing

• Itchy skin or rash

Now let’s discuss the different causes of year-round allergies and ways you can prevent them.

Dust and Dust Mite Allergies

Try as we might, dust always finds its way back onto surfaces throughout our homes. Tiny creatures — known as dust mites — can be found living in this dust, feeding on tiny skin flakes. Dust mites thrive in warm, humid environments and don’t fare well in extreme temperatures or low humidity. Dead mites and their waste can cause an allergic reaction in many people.⁹

To help kick dust mites to the curb, try these tips:⁹

• Cover your mattresses and pillows with dust-proof covers that zip close

• Wash sheets and blankets in hot water weekly to kill dust mites

• Keep humidity low in your house with a dehumidifier

Pet Dander and Saliva Allergies

Our furry friends can trigger allergies all year round with their dander, saliva, and urine. These allergens can be found on all surfaces that pets touch, such as furniture and rugs. Even if you don’t have an animal at home, pet allergens can stick to your clothes from other places you’ve been.¹⁰

To help keep pet allergies to a minimum, try to:¹⁰

• Keep your pet off your bed, or out of your bedroom entirely; keeping them off other furniture like couches and chairs can also help minimize your exposure to allergens

• Dust and vacuum frequently – but be aware that this might stir up more allergens in the air, temporarily making allergies worse

• Brush pets outside when you can to keep dander out of your house

For more tips on managing pet dander allergies, read our guide here.

Mold Allergies

Mold can be found indoors and outdoors, making it one of the most common triggers of allergic reactions. Indoors, it likes to grow in damp places like kitchens, bathrooms, laundry rooms, and basements.¹¹

While most mold and mildew tend to be harmless, there are certain kinds that can be dangerous. Very rarely, some toxic molds can grow and release hazardous substances. The Centers for Disease Control and Prevention notes that mold can be many different colors. No matter the color, it should be properly cleaned to prevent it from growing elsewhere.¹¹

The best way to keep mold at bay in your house is to keep a low humidity environment with a dehumidifier. Regularly cleaning damp rooms and ensuring there is proper airflow in them can also help.

References

1. Mayo Clinic. Hay fever. July 16, 2020. Accessed from: https://www.mayoclinic.org/diseases-conditions/hay-fever/symptoms-causes/syc-20373039. Accessed 18 Dec. 2024.

2. Asthma and Allergy Foundation of America. Pollen Allergy. February 2022. Accessed from: https://www.aafa.org/pollen-allergy/. Accessed 18 Dec. 2024.

3. Asthma and Allergy Foundation of America. Insect Allergies. October 2015. Accessed from: https://www.aafa.org/insect-allergy/. Accessed 18 Dec. 2024.

4. American College of Allergy, Asthma, & Immunology. Insect Sting Allergies. February 5, 2018. Accessed from: https://acaai.org/allergies/allergic-conditions/insect-sting-allergies/. Accessed 18 Dec. 2024.

5. American College of Allergy, Asthma, & Immunology. Seasonal Allergies. December 28, 2017. Accessed from: https://acaai.org/allergies/allergic-conditions/seasonal-allergies/. Accessed 18 Dec. 2024.

6. Asthma and Allergy Foundation of America. Mold Allergy. October 2015. Accessed from: https://www.aafa.org/mold-allergy/. Accessed 18 Dec. 2024.

7. American College of Allergy, Asthma, & Immunology. Hay Fever. June 17, 2020. Accessed from: https://acaai.org/allergies/allergic-conditions/hay-fever/. Accessed 18 Dec. 2024.

8. American Academy of Allergy Asthma & Immunology. Indoor Allergens. August 08, 2023. Accessed from: https://www.aaaai.org/tools-for-the-public/conditions-library/allergies/indoor-allergens-ttr. Accessed 18 Dec. 2024.

9. Allergy & Asthma Network. Allergy to Dust Mites. Accessed from: https://allergyasthmanetwork.org/allergies/allergy-to-dust-mites. Accessed 18 Dec. 2024.

10. “Pet Allergy.” Edited by Mitchell Grayson, Asthma & Allergy Foundation of America, 17 Oct. 2024, aafa.org/allergies/types-of-allergies/pet-dog-cat-allergies/. Accessed 11 Dec. 2024.

11. US Centers For Disease and Control Prevention. https://www.cdc.gov/mold-health/about/index.html. Accessed 26 September 2024.

12. https://www.mayoclinic.org/diseases-conditions/hay-fever/in-depth/seasonal-allergies/art-20048343#:~:text=Reduce%20your%20exposure%20to%20allergy,if%20you%20do%20outside%20chores. Accessed 18 Dec. 2024.

13. https://www.merckmanuals.com/home/immune-disorders/allergic-reactions-and-other-hypersensitivity-disorders/year-round-allergies#Treatment_v780093. Accessed 18 Dec. 2024.

14. https://allergyasthmanetwork.org/news/seasonal-allergies/. Accessed 18 Dec. 2024.