Spring allergies are getting worse because climate change is physically altering pollen seasons — they now start 20 days earlier, last 10 days longer, and carry 21 percent more pollen than they did in 1990, according to research published in the Proceedings of the National Academy of Sciences. The drugs that still work best are second-generation antihistamines like Zyrtec, Allegra, and Claritin, combined with nasal steroid sprays like Flonase or Nasacort — but timing matters more than most people realize. Experts now recommend starting allergy medications a full month before symptoms typically appear, not after the sneezing starts.
For the millions of older adults managing both seasonal allergies and cognitive health, this shift matters on multiple levels. Over one in three U.S. adults suffer from seasonal allergies, and the wrong medication choice — particularly first-generation antihistamines like Benadryl — can impair memory, increase fall risk, and worsen confusion in people with dementia or mild cognitive impairment. This article breaks down why pollen seasons keep intensifying, which medications are safest and most effective for brain-health-conscious adults, and what new treatments are emerging in 2025 and 2026.
Table of Contents
- Why Are Spring Allergies Getting Worse Every Year?
- The Hidden Cognitive Cost of Untreated Allergies and Wrong Medications
- Which Over-the-Counter Antihistamines Actually Work Best in 2026
- Why Nasal Steroid Sprays May Be the Smarter First Choice
- Allergy Medication Interactions and Dementia-Related Risks
- The Rising Asthma Risk and What It Means for Vulnerable Adults
- New Allergy Treatments on the Horizon
- Conclusion
- Frequently Asked Questions
Why Are Spring Allergies Getting Worse Every Year?
The short answer is that warmer temperatures and rising carbon dioxide levels are supercharging plant growth and pollen output. The freeze-free growing season has lengthened in 87 percent of 198 U.S. cities analyzed by Climate Central — by an average of 21 extra days since 1970. The Pacific Northwest leads with 31 additional frost-free days. More growing days means trees and grasses have a longer window to produce pollen, and higher CO₂ concentrations make each plant produce more of it.
If carbon pollution continues at current rates, the United States could face up to a 200 percent increase in total pollen production by the end of this century. The 2026 season is shaping up to be especially brutal. AccuWeather meteorologists project that 29 states may see above-average pollen levels this year, with the Ohio Valley — Ohio, Indiana, and Kentucky — expected to be among the hardest-hit regions, particularly after spring rainfall encourages rapid plant growth. Tree pollen season has already begun as of early March 2026 across Southern California, southern Arizona, and the Gulf Coast. Portland and Seattle may see dramatically high tree pollen levels earlier than usual. In Atlanta, pollen seasons have been starting earlier and lasting longer, with record-breaking counts occurring primarily since 2020.
The Hidden Cognitive Cost of Untreated Allergies and Wrong Medications
Allergies cause approximately 3.8 million missed work and school days annually in the United States, but the toll on older adults is harder to measure and often overlooked. Chronic nasal congestion disrupts sleep, and poor sleep is one of the most consistent risk factors for cognitive decline. Histamine itself plays a role in brain function — it helps regulate wakefulness and attention — so when allergy symptoms flare or when the wrong antihistamine floods the brain, thinking can get noticeably foggy. The critical warning here is about benadryl (diphenhydramine).
Despite its familiarity, Benadryl is no longer recommended as a first-line allergy treatment, according to Dartmouth Health. It is a first-generation antihistamine that crosses the blood-brain barrier aggressively, causing significant drowsiness, confusion, and impaired coordination. For older adults — especially those with any degree of cognitive impairment — these effects compound existing vulnerabilities. However, if you are caring for someone with dementia who has been taking Benadryl for years, do not stop it abruptly without consulting their physician, as sudden changes in routine medications can also cause confusion and agitation.
Which Over-the-Counter Antihistamines Actually Work Best in 2026
The three main second-generation antihistamines — Allegra (fexofenadine), Zyrtec (cetirizine), and claritin (loratadine) — are all available without a prescription, but they are not interchangeable. Zyrtec is generally considered the most effective of the three, but it is also the most sedating within the group, with drowsiness rates running 3 to 8 percent above placebo. For someone managing early cognitive symptoms or taking other medications that cause drowsiness, that difference matters. Allegra is the least sedating option, with drowsiness rates only 1 to 3 percent above placebo, and it may work better for itchy, watery eyes specifically.
Claritin is the most widely recognized name but is considered slightly less effective overall. A fourth option, Xyzal (levocetirizine), may offer superior relief for sneezing and nasal itching. On price, the differences are notable. Zyrtec starts around $6.20 for a 30-count supply and can go as low as $3.97 with a GoodRx Gold membership. Allegra runs about $11.79 at retail but drops to roughly $2.00 with a GoodRx coupon. Brand-name Claritin costs around $27.99 for 30 tablets, though its generic form is the cheapest second-generation option available. For anyone on a fixed income — common among older adults and their caregivers — generic cetirizine or loratadine purchased in bulk is the most cost-effective route.
Why Nasal Steroid Sprays May Be the Smarter First Choice
Allergists have been saying for years that nasal steroid sprays like Flonase (fluticasone) and Nasacort (triamcinolone) may actually be more effective than oral antihistamines for nasal symptoms — congestion, sneezing, and runny nose. These sprays work by decreasing inflammation directly in the nasal passages rather than blocking histamine throughout the body. Because they act locally, they cause far fewer systemic side effects, which makes them an appealing option for older adults who are already managing multiple medications. The tradeoff is consistency. Nasal steroids work best when taken daily, and they can take several days of regular use before reaching full effectiveness.
This is the opposite of how most people use them — grabbing the bottle only when symptoms flare. For a caregiver managing someone else’s medication routine, adding a daily nasal spray is a small but meaningful commitment. One practical approach is to pair it with an existing daily habit, such as brushing teeth in the morning. The American College of Allergy, Asthma and Immunology recommends starting allergy medications — including nasal sprays — at least one month before symptoms typically appear. In most of the country, that means February for tree pollen and April for grass pollen.
Allergy Medication Interactions and Dementia-Related Risks
One of the least-discussed problems with allergy management in older adults is the anticholinergic burden. Many common medications — not just Benadryl — have anticholinergic properties that can impair memory, cause urinary retention, increase heart rate, and worsen confusion. When a first-generation antihistamine is stacked on top of other anticholinergic drugs that a person may already be taking for overactive bladder, depression, or nausea, the cumulative effect on cognition can be substantial.
A limitation worth noting: even second-generation antihistamines are not entirely free of central nervous system effects in every individual. Cetirizine (Zyrtec), while far safer than diphenhydramine, does cause drowsiness in a meaningful minority of users. If a person with mild cognitive impairment starts Zyrtec and their caregiver notices increased afternoon sleepiness or confusion, switching to fexofenadine (Allegra) is a reasonable next step. Always inform the prescribing physician about over-the-counter allergy medications, because they can interact with cholinesterase inhibitors like donepezil (Aricept) and other dementia-related treatments.
The Rising Asthma Risk and What It Means for Vulnerable Adults
Allergies and asthma are closely linked — allergic inflammation in the airways can trigger or worsen asthma attacks — and climate change is amplifying both. According to Climate Central, just 2 degrees Celsius of warming could result in a 17 percent annual increase in asthma-related emergency room visits among children due to pollen exposure. While that statistic focuses on children, older adults with asthma face similar escalating risks, often with fewer physiological reserves to cope with a severe episode.
For someone with both dementia and reactive airway disease, the inability to clearly communicate breathing difficulty makes the stakes even higher. Caregivers should watch for increased coughing, wheezing, or labored breathing during high-pollen days — especially in individuals who may not be able to articulate that they are having trouble breathing. Keeping windows closed during peak pollen hours (typically mid-morning to early afternoon), using HEPA filters, and showering before bed to remove pollen from hair and skin are non-pharmacological strategies that reduce exposure without adding medication complexity.
New Allergy Treatments on the Horizon
Several new treatments approved or nearing approval in 2025 and 2026 could eventually change how severe allergies are managed. Remibrutinib, marketed as Rhapsido by Novartis, became the first oral BTK inhibitor approved by the FDA for chronic spontaneous urticaria — persistent hives that do not respond to standard antihistamines. Depemokimab received FDA approval for severe eosinophilic asthma, offering a new biologic option for patients with the most treatment-resistant forms of allergic airway disease.
DBV Technologies is expected to submit its application for the Viaskin Peanut Patch in the first half of 2026, targeting food allergy desensitization. Further out, researchers are exploring mRNA-based allergy vaccines and microbiome-based treatments, though both remain in early-stage research. These approaches aim to retrain the immune system rather than simply blocking its overreaction, which could eventually reduce or eliminate the need for daily symptom management. For now, though, the practical reality for most allergy sufferers — including older adults and their caregivers — remains a combination of avoidance strategies, properly timed medications, and careful attention to side-effect profiles.
Conclusion
Spring allergy seasons are measurably worse than they were a generation ago, and the trend is accelerating. Earlier starts, longer durations, and heavier pollen loads mean that the old strategy of popping a Benadryl when symptoms hit is not only ineffective but potentially harmful — especially for older adults and anyone with cognitive concerns.
The better approach is to start a second-generation antihistamine and a nasal steroid spray at least a month before pollen season hits your region, choose medications with the lowest sedation risk for your situation, and keep your physician informed about every over-the-counter product in the mix. For caregivers managing allergy symptoms in someone with dementia, the priority is straightforward: avoid first-generation antihistamines entirely, monitor for sedation even with safer alternatives, and reduce pollen exposure through environmental controls. Allergies are not life-threatening for most people, but the cognitive side effects of poor treatment choices can meaningfully worsen quality of life for those already navigating memory loss and confusion.
Frequently Asked Questions
Is Benadryl safe for older adults with dementia?
No. Benadryl (diphenhydramine) is a first-generation antihistamine with strong anticholinergic properties that can worsen confusion, cause excessive sedation, and increase fall risk. Dartmouth Health and other medical sources no longer recommend it as a first-line allergy treatment for any age group, and it is especially risky for people with cognitive impairment.
Which allergy medication causes the least drowsiness?
Allegra (fexofenadine) is the least sedating second-generation antihistamine, with drowsiness rates only 1 to 3 percent above placebo. It is generally the safest choice when sedation is a primary concern.
When should I start taking allergy medicine for spring?
The American College of Allergy, Asthma and Immunology recommends starting at least one month before your symptoms typically begin. For most of the U.S., that means starting in February for tree pollen allergies and April for grass pollen.
Are nasal steroid sprays better than antihistamine pills?
For nasal symptoms specifically — congestion, sneezing, runny nose — experts say nasal steroid sprays like Flonase and Nasacort may be more effective than oral antihistamines. However, they must be used consistently every day and can take several days to reach full effect.
Can allergies make dementia symptoms worse?
Indirectly, yes. Untreated allergies disrupt sleep, and chronic poor sleep is a known risk factor for cognitive decline. Additionally, the wrong allergy medications — particularly those with anticholinergic properties — can directly impair memory and worsen confusion.
Why is the 2026 allergy season expected to be so bad?
AccuWeather projects 29 states may see above-average pollen levels in 2026. Warmer temperatures have extended the frost-free growing season across 87 percent of U.S. cities analyzed, and rising CO₂ levels are boosting pollen production per plant. The Ohio Valley is expected to be one of the hardest-hit regions.
