Climate change is reshaping the landscape of allergic disease in ways that affect both patients and the diagnostic workflows that support their care. Spring allergy season is arriving earlier, lasting longer, and hitting patients harder than in previous years. For clinical laboratories, this shift matters. As more patients seek answers, labs are increasingly central to helping clinicians diagnose and manage allergic disease.

Laboratory directors and their teams need to understand both the science driving these changes and the expanded role labs can play in responding to them.

A season that no longer follows the calendar

For decades, clinicians and patients could roughly anticipate when allergy season would begin and end, yet these predictable timelines are not as consistent. Warmer global temperatures, rising carbon dioxide (CO₂) levels, and increased rainfall are directly altering the intensity, duration, and geographic spread of allergen exposures.¹ Recent projections suggest that pollen emissions in North America could increase by 16–40%, with pollen seasons lengthening by up to 19 days.²

What this means clinically is that tree pollen, which historically peaked in early spring, is now extending further into the summer and increasingly overlapping with grass pollen seasons that are also beginning earlier. These overlapping exposures complicate symptom evaluation significantly. A patient presenting in May with rhinitis, cough, or wheezing can no longer be assessed through the lens of a single seasonal trigger. Relying solely on patient history or seasonal timing may no longer provide sufficient diagnostic clarity.

Rising CO₂ levels also affect mold allergenicity in ways that compound the problem. Research on Aspergillus fumigatus — one of the most common allergenic mold species found in both indoor and outdoor environments — found that fungi grown under present-day CO₂ levels exhibited significantly higher allergenicity compared to those grown at pre-industrial levels, suggesting that rising atmospheric CO₂ may be meaningfully increasing the allergenic potency of common molds.³ Increased rainfall and humidity further drive indoor allergen proliferation, including dust mites and mold.

For clinical laboratories, this environmental complexity creates a more demanding diagnostic landscape where comprehensive testing is becoming increasingly necessary rather than optional.

Adults with no prior history: A growing clinical challenge

One of the more striking trends clinicians are reporting is a rise in adult patients presenting with allergy-like symptoms for the first time. These individuals have had no pediatric history or prior sensitization on record. This is consistent with what is now known about cumulative allergen exposure: allergy is a threshold disease, and as pollen seasons intensify and overlap, previously sub-threshold exposures are crossing into clinically significant territory for more people.

Up to 90% of children and 60% of adults with asthma have allergic triggers that can induce or worsen symptoms.⁴^,⁵ Even in patients with chronic obstructive pulmonary disease (COPD), allergic sensitization plays a role in nearly 30% of cases.⁶ Yet many of these patients — and the clinicians managing them — are unaware that allergy is a driver, particularly when symptoms present atypically or outside of traditionally expected seasons.

Nonallergic triggers add another layer of complexity. Temperature fluctuations, elevated ozone levels, and particulate matter can worsen airway inflammation independent of allergen exposure.⁷ A patient whose symptoms spike during a period of poor air quality may be experiencing nonallergic exacerbation, allergic exacerbation, or both simultaneously. Without objective data, distinguishing between these scenarios is difficult, and the treatment implications are meaningfully different.

How clinical laboratories enable precise allergy diagnosis

This is precisely where clinical laboratories provide value that cannot be replicated by clinical impression alone. Specific immunoglobulin E (IgE) testing enables clinicians to identify which allergens, if any, are driving a patient’s symptoms and to map those triggers against the allergen profiles most prevalent in their geographic region.

Multiple national and international guidelines support the use of specific IgE testing to characterize individual sensitization patterns in patients with upper and lower respiratory symptoms.⁸ Clinical laboratories that offer region-specific environmental allergen panels make it possible for clinicians to conduct comprehensive trigger assessments efficiently, without ordering an unwieldy array of individual tests.

This matters operationally as well as clinically. As allergy seasons grow longer, the volume of patients presenting with respiratory symptoms earlier in the year is increasing. Laboratories that have established testing workflows and can turn around specific IgE results quickly are positioned to be meaningful partners in managing that patient volume — helping primary care clinicians, allergists, and pulmonologists make faster, better-informed decisions before symptoms escalate.

Moving beyond empiric treatment

A long-standing challenge in allergy management is the tendency toward empiric, symptom-driven treatment, such as antihistamines prescribed because the patient has sneezing and itchy eyes  a steroid inhaler added because of wheeze, without a clear picture of what is actually driving disease. This approach can control symptoms for some patients, but it leaves the root cause unaddressed and often falls short in patients with complex or multiple sensitizations.

Among individuals with allergies, 80–90% are sensitized to more than one allergen.⁹ When multiple allergic triggers overlap with nonallergic environmental stressors, the cumulative burden can overwhelm what would otherwise be manageable with appropriate trigger avoidance. A patient sensitized to tree pollen, dust mites, and pet dander may keep symptoms under adequate control through most of the year, but during a peak pollen overlap period compounded by high ozone days, that cumulative threshold is exceeded, and standard medications may no longer be sufficient.

Objective laboratory data enables a more personalized approach. When clinicians know which specific allergens are sensitizing a patient, they can counsel on targeted avoidance, consider allergen immunotherapy candidacy, and make more informed choices regarding pharmacotherapy. This shifts allergy management from reactive to proactive, which is especially important now that "season" is an increasingly unreliable concept.

A practical case for lab engagement

For laboratory directors and managers considering how to position their services for this evolving need, the opportunity is clear. Specific IgE testing is an established methodology backed by a strong evidence base and well-defined clinical guidelines. At the same time, the patient population is growing, including adults presenting earlier in the season with more complex symptom profiles and, in many cases, no prior allergy diagnosis. Many of the primary care clinicians seeing these patients first may also lack timely access to allergy specialists or streamlined referral pathways.

Laboratories that proactively communicate with clinical partners about available allergen panels, regional allergen trends, and testing protocols can help close an important gap in care. Even simple measures, such as ensuring clinicians are aware of panel options or providing interpretive context alongside results, can improve their ability to act confidently on testing insights.

The diagnostic infrastructure laboratories provide is not peripheral to allergy care. As environmental changes continue to drive earlier symptom onset, overlapping allergen exposures, and higher rates of sensitization across the population, laboratory testing is becoming increasingly central to effective diagnosis and management.

References

1. Making the connection: Climate changes allergies and asthma. American Public Health Association, Climate for Health, and ecoAmerica. Accessed June 15, 2026. https://www.apha.org/getcontentasset/9eb942e2-8b95-4b17-8994-65ad03c9670b/7ca0dc9d-611d-46e2-9fd3-26a4c03ddcbb/asthma_allergies.pdf.
2. Pershad AR, Krishnan R, Lee E, et al. How climate change is impacting allergic rhinitis: A scoping review. Laryngoscope. 2025;135(8):2670-2682. doi:10.1002/lary.32124.
3. Lang-Yona N, Levin Y, Dannemiller KC, et al. Changes in atmospheric CO2 influence the allergenicity of Aspergillus fumigatus. Glob Chang Biol. 2013;19(8):2381-8. doi:10.1111/gcb.12219. 
4. Allen-Ramey F, Schoenwetter WF, Weiss TW, et al. Sensitization to common allergens in adults with asthma. J Am Board Fam Pract. 2005;18(5):434-9. doi:10.3122/jabfm.18.5.434. 
5. Høst A, Halken S. Practical aspects of allergy-testing. Paediatr Respir Rev. 2003;4(4):312-8. 
6. Wiginton K. Household hazards for people with COPD. WebMD. January 4, 2021. Accessed June 15, 2026. https://www.webmd.com/lung/copd/features/household-hazards-for-people-with-copd.
7. American Lung Association editorial staff. Too hot? How to not trigger your asthma. American Lung Association. May 2, 2024. Accessed June 15, 2026. https://www.lung.org/blog/asthma-heat-triggers.
8. Wickman M. When allergies complicate allergies. Allergy. 2005;60 Suppl 79:14-8. doi:10.1111/j.1398-9995.2005.00852.x. 
9. Calderón MA, Cox L, Casale TB, Moingeon P, Demoly P. Multiple-allergen and single-allergen immunotherapy strategies in polysensitized patients: looking at the published evidence. J Allergy Clin Immunol. 2012;129(4):929-34. doi:10.1016/j.jaci.2011.11.019.