Tree Pollen Counts
Are on the Rise

As spring emerges across the country, so too does a less welcome seasonal visitor: tree pollen. Recent data shows that tree pollen counts have reached record highs in many regions, exceeding historical averages. This surge is causing considerable distress for millions of allergy sufferers who find themselves reaching for tissues and antihistamines more frequently than ever before. At our clinic, we have observed a significant uptick in patients reporting severe symptoms, from persistent congestion to itchy, watery eyes — clear indicators that we may be entering one of the most challenging allergy seasons in recent memory.

The Data: Understanding the Rise
in Tree Pollen

Recent analyses indicate that tree pollen levels in California have been rising, leading to more pronounced allergy seasons. The Asthma and Allergy Foundation of America (AAFA) reported in their 2024 Allergy Capitals™ report that several California cities rank among the top 100 most challenging places for seasonal allergies, with high tree pollen scores contributing significantly to these rankings.
Climate change plays a role in these trends, with warmer temperatures causing pollen seasons to start earlier and last longer. AccuWeather’s 2025 predictions suggest that tree, grass, and weed pollen levels will be elevated across many regions, including California, leading to intensified allergy seasons. Pollen counts are expected to grow nearly 40% in the coming decades, leading to more intense allergies. In Northern California, allergy season typically spans from early March to mid-June. Various factors, including temperature and precipitation, influence pollen counts during this period.

Why Are Pollen Levels Increasing?

Climate Change Extending Pollen Seasons

Rising global temperatures and increased carbon dioxide levels in the atmosphere are fundamentally altering how plants reproduce. Research shows that these climate shifts are causing flowering plants to produce pollen in significantly greater quantities. Some studies indicate that up to 40% more pollen per plant will be produced in the coming decades. Additionally, the chemical composition of the pollen itself appears to be changing, potentially making it more allergenic and problematic for sensitive individuals.

Longer Growing Seasons

As winters become shorter and spring arrives earlier across many regions, plants have extended periods to release pollen grains into the environment. What once was a relatively concentrated 6-8-week pollen season in many areas has now stretched to 3-5 months of high exposure. This prolonged release means that sensitive individuals face not only higher peak concentrations but also much longer durations of exposure, leaving little opportunity for symptom relief throughout the extended season.

Changes in Precipitation Patterns

Shifting weather patterns have created new challenges for allergy sufferers. While rain typically washes pollen in the air to the ground, providing temporary relief, the increasingly common pattern of drought followed by brief, intense rainfall can worsen conditions. During dry periods, pollen accumulates and becomes more concentrated; when followed by thunderstorms, the pollen grains rupture into smaller, more easily inhaled particles that penetrate deeper into the respiratory system, potentially triggering more severe reactions.

Urban Landscape Choices and Their Effects

Many urban and suburban communities have inadvertently contributed to rising pollen counts through landscape design choices. The preference for male cultivars of trees and shrubs (which produce pollen rather than seeds or fruit) in municipal plantings creates what allergists call “botanical sexism” — resulting in unnaturally high concentrations of allergenic species in populated areas. Additionally, the limited diversity in urban landscaping means that when common species like oak, maple, or birch trees release pollen, there’s little buffer of non-allergenic plants to mitigate the impact.

Health Impacts of Higher Tree
Pollen Exposure

Common Allergy Symptoms

The surge in tree pollen concentrations has intensified seasonal allergy symptoms for millions of Americans. Patients frequently report persistent nasal congestion, sneezing fits, and postnasal drip that disrupts sleep and daily activities. Itchy, watery eyes have become particularly problematic, with many individuals experiencing symptoms severe enough to impair driving and computer work. Additionally, we’re seeing more complaints of scratchy throats, ear pressure, and the distinctive “allergic shiners” — dark circles under the eyes caused by congested sinuses. For many, these symptoms are no longer merely annoying but have become genuinely debilitating, affecting work performance and quality of life.

More Severe Reactions in Previously Mild Allergy Sufferers

Our clinic has witnessed a concerning trend: patients with historically manageable pollen allergies now experiencing dramatically intensified responses. The higher environmental pollen load appears to be overwhelming the immune system’s typical threshold for reaction, triggering more pronounced inflammatory responses even in individuals who previously required minimal intervention. Many patients report that their once-reliable over-the-counter medications are no longer sufficient to control their symptoms. Perhaps most troubling is the increasing incidence of lower respiratory involvement, with more people developing allergic asthma symptoms like chest tightness, wheezing, and shortness of breath during peak pollen days.

Cross-Reactivity With Other Allergens, Such as Grass Pollen

Cross-reactivity has become more clinically significant as higher pollen counts create a perfect storm of allergen exposure. Patients sensitized to tree pollens often experience exaggerated reactions when subsequently exposed to grass pollens due to similar protein structures recognized by the immune system. This “priming effect” means that once the immune system is activated by early-season tree pollen, the threshold for reaction to later-emerging allergens decreases substantially. We’re seeing more patients who never previously reacted to multiple pollen types now experiencing continuous symptoms from early spring through late summer as their sensitized immune systems struggle to reset between different pollen seasons. This extended period of reactivity often leads to chronic inflammation, making tissues hypersensitive to even non-allergenic irritants like strong odors or temperature changes.

Who Is the Most at Risk of Seasonal Allergies?

While tree pollen allergies can affect anyone, specific populations face significantly higher risks and more severe consequences:

Children and young adults often bear the heaviest burden, with studies showing that individuals between 10 and 30 years old experience the most intense immunological responses to allergens.
Those with a family history of allergies or asthma have a genetic predisposition that increases their likelihood of developing pollen sensitivities by up to 80%.
Individuals with existing allergic conditions, such as eczema or food allergies, face more significant risks due to their already hypervigilant immune systems.
Older people. In addition, the incidence of allergy in older patients is on the rise and has almost doubled in the past few decades. Many individuals in their 40s, 50s, 60s, 70s, or even older are presenting to our office with the new onset of environmental allergies, including pollen.

Previous allergy history plays a crucial role in predicting susceptibility, as the immune system demonstrates a “memory” for allergen exposure — patients who experienced even mild tree pollen reactions in past seasons frequently develop more pronounced symptoms with each subsequent exposure. These allergies create cascading health effects beyond the immediate symptoms, with asthma exacerbations being perhaps the most dangerous secondary impact. Pollen-induced asthma attacks can be particularly severe during early morning hours when pollen counts typically peak and coincide with the body’s naturally lower cortisol levels. Sleep disturbances represent another significant consequence, as nighttime congestion and coughing create a cycle of fatigue that compounds allergy symptoms and reduces the body’s natural resilience to inflammatory responses.

Prevention and Treatment Options

Environmental Controls and Behavior Modifications

Minimizing pollen exposure requires a strategic approach to daily activities during peak season. We recommend checking local pollen forecasts and scheduling outdoor activities for lower-count periods, typically in late afternoons or after gentle rainfall. Keep windows closed, particularly overnight and early morning when pollen release is highest. If you have to keep your windows open, try to install a pollen filter on them, which will allow fresh air in but can help prevent pollen from coming in. You may also consider using HEPA air purifiers in bedrooms and main living spaces. After spending time outdoors, change clothes immediately and shower before bedtime to remove pollen from hair and skin. For those with severe sensitivities, consider wearing oversized sunglasses and wide-brimmed hats during outdoor activities to reduce eye and facial exposure. These simple adjustments can significantly reduce your overall pollen burden.

Over-the-Counter Medication

The foundation of symptom management for many sufferers begins with readily available allergy medication designed to alleviate symptoms without requiring a prescription. Second-generation antihistamines like cetirizine, loratadine, and fexofenadine offer effective relief without the level of drowsiness associated with older formulations. Intranasal corticosteroid sprays can dramatically reduce nasal inflammation and congestion when used consistently, beginning 1-2 weeks before peak season. Saline rinses and nasal irrigation systems help physically flush pollen from nasal passages, while decongestants can provide temporary relief for severe congestion. For eye symptoms, antihistamine eye drops offer targeted relief. While these options work well for many patients with mild to moderate symptoms, they’re most effective when started before symptoms appear and used consistently throughout the pollen season.

Advanced Treatments Available at Our Clinic

For patients experiencing inadequate relief from over-the-counter options, our clinic offers comprehensive treatment solutions tailored to your specific allergy profile. Prescription-strength antihistamines, nasal sprays, and leukotriene modifiers can enhance symptom control under medical supervision.
For long-term relief, we specialize in immunotherapy treatments that address the underlying cause of allergies rather than just managing symptoms. Traditional allergy shots (including cluster immunotherapy) involve regular in-office injections of gradually increasing allergen concentrations to retrain your immune system, with high success rates for most patients. For those seeking a more convenient option, we also offer allergy drops (sublingual immunotherapy), allowing at-home administration by placing liquid extracts under the tongue daily.
Both approaches can significantly reduce sensitivity to tree pollens over time, often providing relief beyond the treatment period and potentially preventing the development of new allergies or asthma.

The Allergy & Asthma Clinic Is a Top
Destination for Allergy Treatment in California

The Allergy & Asthma Clinic is a premier destination for allergy and respiratory care in California, serving the Bay Area with distinction for over 30 years. Led by Dr. Andrew C. Engler, a Stanford-educated physician recognized as a Castle Connolly Top Doctor for 25 consecutive years, our clinic offers comprehensive allergy testing, immunotherapy options, and specialized treatments for conditions ranging from seasonal allergies to complex immunological disorders. We have a team of board-certified specialists with impressive credentials from leading institutions, including Yale, UCLA, Stanford, and the University of Pennsylvania. Our patients benefit from personalized care plans incorporating innovative treatments and attentive service in a warm, welcoming environment designed to address their unique health needs.

Conclusion

As tree pollen counts continue to rise, taking proactive steps is essential for managing your allergy symptoms and protecting your quality of life. While environmental changes present new challenges, remember that you don’t have to suffer through allergy season. Our experienced team at the Allergy & Asthma Clinic offers comprehensive testing, personalized treatment plans, and the latest therapeutic options to help you breathe easier.
Contact us today to schedule a consultation and discover how we can help you find relief from seasonal allergies — because life is too short to spend it sneezing.

Tree Pollen Counts
Are on the Rise

Table Of Contents

Table Of Contents

The Data: Understanding the Rise
in Tree Pollen

Why Are Pollen Levels Increasing?

Climate Change Extending Pollen Seasons

Longer Growing Seasons

Changes in Precipitation Patterns

Urban Landscape Choices and Their Effects

Health Impacts of Higher Tree
Pollen Exposure

Common Allergy Symptoms

More Severe Reactions in Previously Mild Allergy Sufferers

Cross-Reactivity With Other Allergens, Such as Grass Pollen

Who Is the Most at Risk of Seasonal Allergies?

Prevention and Treatment Options

Environmental Controls and Behavior Modifications

Over-the-Counter Medication

Advanced Treatments Available at Our Clinic

The Allergy & Asthma Clinic Is a Top
Destination for Allergy Treatment in California

Conclusion

Office Hours

Allergy Shot Hours

Office Hours

Allergy Shot Hours

Tree Pollen Counts Are on the Rise

Table Of Contents

Table Of Contents

The Data: Understanding the Rise in Tree Pollen

Why Are Pollen Levels Increasing?

Climate Change Extending Pollen Seasons

Longer Growing Seasons

Changes in Precipitation Patterns

Urban Landscape Choices and Their Effects

Health Impacts of Higher Tree Pollen Exposure

Common Allergy Symptoms

More Severe Reactions in Previously Mild Allergy Sufferers

Cross-Reactivity With Other Allergens, Such as Grass Pollen

Who Is the Most at Risk of Seasonal Allergies?

Prevention and Treatment Options

Environmental Controls and Behavior Modifications

Over-the-Counter Medication

Advanced Treatments Available at Our Clinic

The Allergy & Asthma Clinic Is a Top Destination for Allergy Treatment in California

Conclusion

Office Hours

Allergy Shot Hours

Office Hours

Allergy Shot Hours

Tree Pollen Counts
Are on the Rise

The Data: Understanding the Rise
in Tree Pollen

Health Impacts of Higher Tree
Pollen Exposure

The Allergy & Asthma Clinic Is a Top
Destination for Allergy Treatment in California