If you check the pollen count and it's finally trending down, but you still feel wrecked, you're not imagining it. Pollen isn't the only thing floating around outside in August — mold is having its biggest moment of the year.
Mold gets far less attention than pollen, but outdoor mold spore counts typically stay elevated from July through early October, often outnumbering pollen counts by late summer. Warm, humid air and decaying plant matter make ideal conditions for mold to thrive, and unlike a single plant's bloom window, mold spores get released continuously as long as conditions stay warm and wet (sources linked at the end). That means an itchy nose, watery eyes, or sudden asthma flare-up in August is just as likely to be mold as it is ragweed.
Two mold species, Alternaria and Cladosporium, are responsible for the vast majority of outdoor mold allergy symptoms in the U.S. Both peak in warm, humid conditions and release spores most heavily on hot, breezy afternoons — which is why symptoms can spike even on a day with a "low" pollen forecast. Rain doesn't wash mold away either; a rainy stretch followed by heat and humidity tends to make counts worse, not better.
To make matters worse, ragweed season typically starts in mid-to-late August, right as mold levels are already elevated. For anyone sensitive to both, this creates a period of compounding allergen exposure that's often more intense than the individual pollen or mold season alone — one reason "back to school allergies" can feel like the worst stretch of the year.
Antihistamines and nasal sprays treat mold allergy symptoms in the moment, but they don't change how the immune system responds to mold spores — so symptoms come right back the next time counts spike.
Sublingual immunotherapy works differently: it gradually trains the immune system to become less reactive to specific allergens, including common outdoor molds, over time. Because SLIT addresses the underlying immune response rather than just the symptoms, many people using allergy drops for mold report fewer and milder flare-ups during peak late-summer conditions.
If your symptoms tend to worsen in late summer even when pollen counts are low, mold sensitivity is worth ruling out. The next step is identifying your specific triggers — mold, ragweed, or both are common late-summer culprits — and exploring whether at-home allergy immunotherapy fits your routine.
Can you be allergic to mold the same way you're allergic to pollen?
Yes. Mold allergy works the same way as pollen allergy — the immune system overreacts to proteins in mold spores, triggering symptoms like sneezing, congestion, itchy eyes, and in some people, asthma flare-ups.
How long does it take for allergy drops to help with mold allergies?
As with other allergens, immunotherapy for mold is a gradual process. Many people notice fewer and milder symptoms over the course of several months as the immune system adjusts, rather than immediately.
UW Health. Outdoor Allergens. Patients & Families.
Aggarwal S, et al. Increased duration of pollen and mold exposure are linked to climate change. PMC, 2021.
Atlanta Allergy & Asthma. Are You Allergic to Mold?.
Asthma and Allergy Foundation of America. Allergy Capitals Report.
