Author: Louis Krenn MD

Disclaimer: Information is provided for educational use only and should not be considered medical advice. Always consult your physician for medical advice.

Over 50 million Americans experience allergies each year, with seasonal allergies ranking among the most common chronic conditions in the United States. These allergic reactions, also called seasonal allergic rhinitis or hay fever, can significantly impact quality of life, affecting sleep, work productivity, and daily activities. Despite their prevalence, many people don't fully understand what causes their symptoms or the most effective ways to manage them.

Seasonal allergies occur when your immune system overreacts to certain environmental triggers that appear during specific times of the year. While these substances are harmless to most people, your body mistakenly identifies them as dangerous invaders, launching a defensive response that causes those all-too-familiar symptoms: sneezing, runny nose, itchy eyes, and more.

In this comprehensive guide, we'll explore the science behind seasonal allergies, identify common triggers, discuss evidence-based treatment options, and provide practical strategies to help you breathe easier throughout the year.

Key Takeaways 

• Seasonal allergies are caused by an overreaction of the immune system to specific environmental triggers that appear during different seasons
• Common allergens include tree pollen, grass pollen, weed pollen, and mold spores
• Effective management combines avoidance strategies, medication options, and lifestyle modifications
• Over-the-counter and prescription treatments can significantly reduce symptoms when used correctly
• Knowing when to seek medical help is crucial, especially for severe symptoms or when allergies impact your quality of life

Understanding Your Immune System's Response

How Allergic Reactions Develop

When you have seasonal allergies, your body's immune system identifies certain substances as harmful invaders, even though they're generally harmless. This misidentification triggers a cascade of events in your body.

The process begins with sensitization. The first time your body encounters an allergen like pollen, your immune system produces antibodies called Immunoglobulin E (IgE) specific to that allergen. These antibodies attach to immune cells called mast cells, which are found in tissues throughout your body, particularly in areas exposed to the environment, such as your nose, eyes, lungs, and skin.

Later, when you encounter the same allergen again, it binds to the IgE antibodies attached to the mast cells. This binding causes the mast cells to release powerful chemicals like histamine into surrounding tissues. These chemicals are responsible for the inflammation and irritation you experience as allergy symptoms.

This reaction happens quickly—often within minutes of exposure—which explains why stepping outside on a high-pollen day can trigger almost immediate symptoms for those with pollen allergies.

Why Some People Develop Allergies and Others Don't

Allergies have a strong genetic component. If one of your parents has allergies, you have a 30-50% chance of developing them. If both parents have allergies, your risk increases to 60-80%. However, genetics isn't the whole story.

Environmental factors also play a crucial role. Research suggests that early-life exposures to certain substances and environments may influence whether you develop allergies. Some studies support the "hygiene hypothesis," which suggests that our modern, ultra-clean environments may not provide enough microbial exposure for our immune systems to develop correctly, potentially increasing allergy risk.

Other factors that may influence allergy development include:

• The timing and type of allergen exposures during childhood
• Maternal diet during pregnancy
• Whether you were breastfed
• Early exposure to pets or farm animals
• Exposure to tobacco smoke or air pollution

Common Seasonal Allergens

Spring Allergens (February to May)

Spring allergies primarily revolve around tree pollen. As trees begin their reproductive cycle, they release tiny pollen grains that can travel for miles on the wind. Common tree allergens include:

• Oak
• Maple
• Birch
• Cedar
• Pine
• Elm
• Poplar

Tree pollen levels are highest on warm, dry, windy days when pollen can be carried for miles. Rainy days temporarily clear pollen from the air, providing brief relief for allergy sufferers.

Summer Allergens (May to July)

As spring transitions to summer, grass pollen becomes the primary culprit. Common grass allergens include:

• Timothy grass
• Kentucky bluegrass
• Johnson grass
• Bermuda grass
• Orchard grass
• Sweet vernal grass

Grass pollen levels peak in the early morning and again in the early evening. Mowing the lawn can stir up significant amounts of grass pollen, so those with grass allergies might want to delegate this chore or wear a mask when mowing.

Fall Allergens (August to November)

Fall allergies are predominantly caused by weed pollen, with ragweed being the most notorious offender. A single ragweed plant can produce up to one billion pollen grains in a season, and these lightweight particles can travel hundreds of miles on the wind.

Common weed allergens include:

• Ragweed
• Sagebrush
• Pigweed
• Lamb's quarters
• Tumbleweed
• Cocklebur

Ragweed pollen levels peak in mid-September and can remain high until the first hard frost. About 75% of people who are allergic to spring plants are also allergic to ragweed.

Year-Round Allergens

While we typically associate allergies with particular seasons, some outdoor allergens can cause problems year-round or during multiple seasons:

• Mold spores: Outdoor molds thrive in damp, dark environments like piles of leaves, compost heaps, and rotting wood. Mold counts are typically highest during warm, humid weather and can remain elevated until the first hard frost. Unlike pollen, mold doesn't die with the first frost—it simply becomes dormant until conditions improve.
• Climate change impacts: Research indicates that climate change is extending pollen seasons and increasing pollen production. Warmer temperatures and higher CO2 levels are causing plants to produce more pollen over longer periods. Some studies suggest that pollen seasons have lengthened by 10-30 days over the past few decades, with pollen concentrations increasing by 10-20%.

Recognizing Seasonal Allergy Symptoms

Common Symptoms

Seasonal allergy symptoms primarily affect the respiratory system and eyes. Common symptoms include:

• Nasal symptoms: Runny or stuffy nose, sneezing, postnasal drip
• Eye symptoms: Watery, red, itchy, or swollen eyes (allergic conjunctivitis)
• Throat symptoms: Scratchy or sore throat, especially from postnasal drip
• Ear symptoms: Itchy ears or ear fullness
• Sinus pressure: Feeling of fullness or pain in the face
• Fatigue: Tiredness from disrupted sleep or the immune system's response

These symptoms typically last as long as you're exposed to the triggering allergen and may fluctuate in intensity based on pollen or mold counts.

Differentiating Allergies from Colds and COVID-19

It's important to distinguish seasonal allergies from other conditions with similar symptoms:

Characteristic
Seasonal Allergies
Common Cold
COVID-19
Onset
Sudden, upon exposure to allergen
Gradual
Variable
Duration
Weeks or months, as long as allergen is present
7-10 days
Variable
Itchy eyes/nose
Common
Rare
Rare
Sneezing
Common
Sometimes
Rare
Runny/stuffy nose
Common
Common
Sometimes
Fever
Never
Sometimes, low-grade
Common
Body aches
Rare
Mild
Common
Fatigue
Sometimes
Sometimes
Common
Sore throat
Sometimes
Common
Sometimes
Cough
Sometimes
Common
Common
Loss of taste/smell
Rare
Sometimes
Common in some variants

Key differentiators of allergies include:

• Symptoms appear rapidly when exposed to triggers
• Itchy eyes, nose, or throat are prominent
• No fever
• Symptoms last longer than a typical cold
• Thin, clear nasal discharge (versus thicker, colored discharge with infections)

Diagnosing Seasonal Allergies

When to See a Healthcare Provider

Consider consulting with a healthcare provider about your seasonal allergies if:

• Over-the-counter medications don't adequately control your symptoms
• Allergies significantly impact your quality of life, sleep, or daily activities
• You experience wheezing or shortness of breath with your allergy symptoms
• You have persistent sinus infections, headaches, or ear infections
• You're unsure whether your symptoms are due to allergies or another condition
• You're pregnant or have other health conditions that limit your treatment options

A proper diagnosis is essential if you're considering immunotherapy (allergy shots), which requires identifying specific allergens.

Diagnostic Methods

Healthcare providers use several approaches to diagnose seasonal allergies:

1. Medical history: Your provider will ask detailed questions about your symptoms, timing, potential triggers, family history of allergies, and response to previous treatments.
2. Physical examination: This typically focuses on your eyes, ears, nose, throat, respiratory system, and skin.
3. Allergy testing: There are two main types:
   • Skin prick tests: Small amounts of suspected allergens are placed on your skin, which is then lightly pricked. A small, itchy bump (like a mosquito bite) will form within 15-20 minutes if you're allergic.
   • Blood tests: These measure the amount of allergen-specific IgE antibodies in your blood. Examples include the RAST (radioallergosorbent test) and the ELISA (enzyme-linked immunosorbent assay) test.
4. Elimination and challenge: Sometimes, your provider might suggest avoiding suspected triggers to see if symptoms improve, then reintroducing them in a controlled manner to confirm the diagnosis.

Treatment Options for Seasonal Allergies

Over-the-Counter Medications

Several effective over-the-counter options can help manage seasonal allergy symptoms:

1. Oral antihistamines: These medications block histamine, the chemical responsible for many allergy symptoms. They help relieve sneezing, itching, runny nose, and watery eyes.
   • Non-drowsy options (second-generation): loratadine (Claritin), cetirizine (Zyrtec), fexofenadine (Allegra)
   • Potentially sedating options (first-generation): diphenhydramine (Benadryl), chlorpheniramine
2. Nasal corticosteroids: These anti-inflammatory sprays are the most effective medication for allergic rhinitis. They reduce inflammation in the nasal passages and help with congestion, sneezing, runny nose, and postnasal drip.
   • Examples: fluticasone (Flonase), triamcinolone (Nasacort), budesonide (Rhinocort)
   • Most effective when used daily throughout your allergy season, not just when symptoms occur
3. Decongestants: These medications shrink swollen nasal tissues to help you breathe more easily.
   • Oral options: pseudoephedrine (Sudafed), phenylephrine
   • Nasal sprays: oxymetazoline (Afrin), phenylephrine (Neo-Synephrine)
   • Note: Nasal decongestant sprays should not be used for more than three consecutive days, as longer use can lead to rebound congestion
4. Eye drops: Several types address eye symptoms:
   • Antihistamine drops: ketotifen (Zaditor, Alaway), olopatadine (Pataday)
   • Decongestant drops: naphazoline (Clear Eyes)
   • Mast cell stabilizer drops: cromolyn sodium
   • Artificial tears: help wash allergens from the eyes
5. Combination products: Some products combine an antihistamine with a decongestant or other medications to target multiple symptoms.

Prescription Medications

For more severe or persistent allergies, your healthcare provider might recommend:

1. Prescription-strength antihistamines and corticosteroids: Stronger versions of OTC options.
2. Leukotriene modifiers: These oral medications block leukotrienes, chemicals involved in allergic reactions.
   • Example: montelukast (Singulair)
   • Particularly helpful for people with both allergies and asthma
3. Mast cell stabilizers: These medications prevent mast cells from releasing histamine and other chemicals.
   • Nasal sprays: cromolyn sodium
   • Eye drops: lodoxamide, nedocromil
4. Anticholinergics: Nasal sprays like ipratropium bromide (Atrovent) help control runny nose.
5. Biologics: For severe cases, especially those with associated conditions like asthma, injectable biologics that target specific pathways in allergic reactions may be prescribed.
   • Example: omalizumab (Xolair), which binds to IgE antibodies

Immunotherapy Options

For long-term relief, especially for severe or persistent allergies, immunotherapy gradually desensitizes your immune system to specific allergens:

1. Allergy shots (subcutaneous immunotherapy): A series of injections containing small, gradually increasing amounts of your specific allergens. Treatment typically involves:
   • Build-up phase: Shots every 1-2 weeks for several months
   • Maintenance phase: Monthly shots for 3-5 years
   • Potential for long-lasting relief even after treatment ends
2. Sublingual immunotherapy: Tablets or drops placed under the tongue that contain small amounts of specific allergens.
   • FDA-approved tablets exist for grass pollen, ragweed, and dust mite allergies
   • Generally taken daily at home
   • First dose is typically given in a medical setting to monitor for reactions

Immunotherapy is the only treatment that can alter the underlying allergic disease rather than just treating symptoms. Success rates for reducing symptoms and medication needs range from 70% to 85%.

Lifestyle and Environmental Management

Reducing Exposure to Seasonal Allergens

While complete avoidance of outdoor allergens is impractical, these strategies can help reduce your exposure:

1. Track pollen and mold counts: Many apps and websites provide daily allergen forecasts. The National Allergy Bureau also offers reports for various regions.
2. Time your outdoor activities: Pollen counts are typically highest in the morning (5-10 AM) and on warm, dry, windy days. Consider:
   • Scheduling outdoor activities for late afternoon or after a rainfall
   • Limiting outdoor time on high pollen days
   • Wearing a mask designed to filter pollen when gardening or mowing
3. Create an allergen barrier:
   • Wear sunglasses to protect your eyes from pollen
   • Consider a wide-brimmed hat to keep pollen from settling in your hair
   • Change clothes and shower after spending time outdoors to remove pollen
   • Use a saline nasal rinse to wash away allergens in your nasal passages
4. Home management:
   • Keep windows closed during high pollen seasons; use air conditioning if possible
   • Use high-efficiency air purifiers with HEPA filters
   • Change clothes in the laundry room or bathroom rather than bedroom
   • Wash bedding weekly in hot water
   • Consider removing shoes at the door to avoid tracking pollen inside
   • Vacuum regularly with a HEPA-filter vacuum
   • Keep pets that go outdoors off furniture and out of bedrooms
5. Reduce mold exposure:
   • Clean gutters and ensure proper drainage around your home
   • Remove fallen leaves and avoid compost piles if you're mold-sensitive
   • Keep the humidity in your home below 50%
   • Ensure bathroom, kitchen, and basement areas are well-ventilated

Diet and Lifestyle Factors

While research is still evolving, some evidence suggests certain lifestyle factors may influence allergy symptoms:

1. Anti-inflammatory diet: Some studies suggest that diets rich in fresh fruits, vegetables, whole grains, and omega-3 fatty acids may help reduce allergic inflammation. Foods with natural antihistamine or anti-inflammatory properties include:
   • Fatty fish (salmon, mackerel)
   • Fruits and vegetables high in quercetin (apples, berries, onions, kale)
   • Probiotic-rich foods (yogurt, kefir, sauerkraut)
   • Turmeric, ginger, and other anti-inflammatory spices
2. Hydration: Staying well-hydrated helps thin mucus secretions and supports overall immune function.
3. Exercise: Regular moderate exercise may help reduce allergy symptoms by improving circulation and immune function. Consider indoor exercise on high pollen days.
4. Stress management: Chronic stress can worsen allergy symptoms by increasing inflammation. Techniques like meditation, deep breathing, and adequate sleep may help.
5. Saline irrigation: Using a neti pot or saline spray to rinse your nasal passages can physically remove allergens and thin mucus.

Special Considerations

Seasonal Allergies in Children

Children may experience allergies differently than adults:

• Symptoms may be less specific, manifesting as irritability, sleep disturbances, or decreased appetite
• Children may rub their noses upward (the "allergic salute"), creating a crease across the nose
• Dark circles under the eyes ("allergic shiners") may be prominent
• Children may have more ear and sinus infections alongside allergies

Management approaches should be age-appropriate:

• For very young children, environmental controls are especially important
• Medication dosing must be adjusted for age and weight
• Some medications are not approved for young children
• Involve children in age-appropriate self-management, like tracking symptoms or reminding them about medications

Allergies and Asthma

Approximately 60-80% of people with asthma have allergies, and allergens are common asthma triggers. This connection, known as the "allergic march" or "atopic march," represents the progression from allergies to asthma many people experience.

If you have both conditions:

• Controlling your allergies is essential for asthma management
• Be vigilant about peak flow monitoring during allergy season
• Make sure your asthma action plan addresses seasonal changes
• Consider seeing an allergist or pulmonologist who can manage both conditions
• Some medications, like leukotriene modifiers, target both conditions

Pregnancy and Allergies

Pregnancy can affect allergies in unpredictable ways:

• Some women experience improvement due to natural immune system changes
• Others find their symptoms worsen
• Nasal congestion is common during pregnancy, even without allergies (rhinitis of pregnancy)

Treatment considerations during pregnancy:

• Always consult your healthcare provider before taking any medication
• Some antihistamines (like loratadine and cetirizine) are generally considered safe
• Nasal saline rinses are safe and can be helpful
• Some nasal corticosteroids may be used if the benefits outweigh the risks
• Avoid decongestants, especially in the first trimester

Emerging Research and Treatments

Climate Change and Allergies

Research indicates that climate change is significantly impacting seasonal allergies:

• Longer growing seasons extend allergy seasons by 2-4 weeks in many regions
• Higher carbon dioxide levels increase pollen production in many plants
• More frequent extreme weather events can affect pollen distribution
• Changes in precipitation patterns influence mold growth
• Geographic ranges of allergenic plants are shifting

A study in the journal PNAS found that North American pollen seasons start about 20 days earlier and have 21% more pollen than in 1990. This trend is expected to continue, potentially increasing the prevalence and severity of seasonal allergies.

New and Upcoming Treatments

The field of allergy treatment continues to evolve:

• New biologics targeting specific immune pathways (beyond omalizumab)
• Improved sublingual immunotherapy options for more allergen types
• Novel drug delivery systems for more effective medication distribution
• Potential for gene therapy approaches in the future
• Continued refinement of personalized treatment approaches based on specific allergen sensitivities and individual immune responses

Resources for Further Reading

1. National Allergy Bureau: Pollen and mold counts across the U.S. https://www.aaaai.org/nab
2. American Academy of Allergy, Asthma, & Immunology (AAAAI): Patient information on allergies and treatments. https://www.aaaai.org/conditions-treatments/allergies
3. American College of Allergy, Asthma and Immunology: Allergy management resources https://acaai.org/allergies/
4. National Institute of Environmental Health Sciences: Environmental factors in allergies https://www.niehs.nih.gov/health/topics/conditions/allergies/index.cfm
5. Centers for Disease Control and Prevention: Allergies and Hay Fever https://www.cdc.gov/nchs/fastats/allergies.htm

When to Seek Medical Help

Red Flags Requiring Prompt Attention

While seasonal allergies are rarely dangerous, specific symptoms warrant immediate medical attention:

• Severe facial or throat swelling
• Difficulty breathing or shortness of breath
• Wheezing
• Lightheadedness or feeling faint
• Severe asthma attack triggered by allergies
• Symptoms that don't respond to appropriate treatment

These could indicate a more serious allergic reaction or complication requiring emergency care.

Signs You Should Consult an Allergist

Consider seeing an allergist or immunologist if:

• Your symptoms aren't well-controlled with over-the-counter treatments
• Allergies significantly impact your quality of life
• You have co-existing conditions like asthma, sinusitis, or eczema
• You experience allergy symptoms most of the year
• You want to identify your specific triggers through testing
• You're interested in immunotherapy options

Allergists have specialized training in diagnosing and treating allergic conditions and can offer the most current and comprehensive treatment approaches.

Final Thoughts

Seasonal allergies affect millions of Americans, but with proper understanding and management, they don't have to impact your quality of life significantly. You can minimize symptoms and enjoy the changing seasons by identifying your specific triggers, working with healthcare providers when needed, and implementing appropriate environmental controls and treatments.

Remember that allergy management is often a matter of finding the right combination of strategies for your specific situation. What works best may change over time and with different seasons, so be prepared to adjust your approach as needed.

If your allergies are significantly affecting your daily life, sleep, or ability to enjoy outdoor activities, don't hesitate to speak with your family physician. Your physician can help you develop a comprehensive management plan tailored to your specific needs.

References

American Academy of Allergy, Asthma & Immunology. (2023). Allergy Statistics. https://www.aaaai.org/about/news/for-media/allergy-statistics

Asthma and Allergy Foundation of America. (2022). Allergy Facts and Figures. https://aafa.org/allergies/allergy-facts/

Centers for Disease Control and Prevention. (2022). Allergies and Hay Fever. https://www.cdc.gov/nchs/fastats/allergies.htm

Dykewicz, M. S., Wallace, D. V., Amrol, D. J., Baroody, F. M., Bernstein, J. A., Craig, T. J., Finegold, I., Golden, D. B. K., Nassif, S. A., Oppenheimer, J., Portnoy, J. M., Randolph, C. C., Rank, M. A., Santos, C. B. S., Schwartz, L. B., Sher, L., & Shaker, M. (2020). Rhinitis 2020: A practice parameter update. Journal of Allergy and Clinical Immunology, 146(4), 721–767. https://doi.org/10.1016/j.jaci.2020.07.007

National Institute of Allergy and Infectious Diseases. (2022). Pollen Allergy. https://www.niaid.nih.gov/diseases-conditions/pollen-allergy

Pawankar, R., Canonica, G. W., Holgate, S. T., Lockey, R. F., & Blaiss, M. S. (2022). WAO White Book on Allergy: Update 2022. World Allergy Organization. https://www.worldallergy.org/resources/white-book

Ziska, L. H., Makra, L., Harry, S. K., Bruffaerts, N., Hendrickx, M., Coates, F., Saarto, A., Thibaudon, M., Oliver, G., Damialis, A., Charalampopoulos, A., Vokou, D., Heiβwolf, M., Brizuela, E., Villamil-Buenrostro, N., Montes, J. L. G., Czuppon, A., Fiechter, G., Bonnstetter, A., & Crimmins, A. (2019). Temperature-related changes in airborne allergenic pollen abundance and seasonality across the northern hemisphere: a retrospective data analysis. The Lancet Planetary Health, 3(3), e124–e131. https://doi.org/10.1016/S2542-5196(19)30015-4