Who Gets Seasonal Allergies, and Why: Gender, Age and Hormones

Seasonal allergies are among the most common health conditions in the United States. In 2021, 25.7% of adults and 18.9% of children had been diagnosed with a seasonal allergy, according to the National Center for Health Statistics. Who is affected, and when, follows patterns. Gender, age and hormones all appear to play a part, and researchers are still working out how.

What a seasonal allergy is

A seasonal allergy, known clinically as allergic rhinitis or hay fever, begins with sensitization. In some people, the immune system produces IgE antibodies that recognize specific proteins in pollen. On later exposure, those antibodies signal mast cells in the nose and eyes to release histamine and other messengers. The pollen grain is not the cause on its own. The response comes from the body's recognition of it.

Children: more common in boys

In childhood, seasonal allergies are more common in boys. In the 2021 U.S. data, 20.0% of boys and 17.7% of girls had a diagnosed seasonal allergy. Prevalence also rose with age, from 10.4% of children under 6 to 24.2% of those aged 12 to 17 (Zablotsky et al., NCHS, 2023).

A meta analysis of 67 population studies with nearly 594,000 participants found the same pattern worldwide. Before age 11, significantly more boys than girls reported rhinitis symptoms (Pinart et al., International Archives of Allergy and Immunology, 2017).

Adolescence: the balance shifts

Around adolescence, the pattern reverses. In the same meta analysis, adolescents aged 11 to 18 showed a shift toward female predominance. The authors described this as a switch that occurred on every continent studied except Asia, where the male predominance continued past childhood (Pinart et al., 2017). A companion meta analysis found the shift was most pronounced in people who have both allergic rhinitis and asthma, and less pronounced for allergic rhinitis alone (Fröhlich et al., Clinical and Translational Allergy, 2017).

Adults: two measures, two pictures

In adulthood, the answer depends on how prevalence is measured. The international meta analyses found no significant difference between men and women in reported rhinitis symptoms (Pinart et al., 2017; Fröhlich et al., 2017). In the United States, however, women were more likely than men to report a diagnosed seasonal allergy: 29.9% compared with 21.1% in 2021 (Ng and Boersma, NCHS, 2023). The reasons the two measures differ are not yet settled.

How hormones may influence immune response

A shift that begins around puberty points researchers toward sex hormones. The leading hypothesis is that estrogen tends to amplify the allergic type of immune response, while testosterone tends to quiet it. Much of the supporting evidence comes from laboratory and animal research, and studies in people are still limited.

Estrogen. Reviews of the field describe estrogen as enhancing Th2 responses, the branch of the immune system associated with allergy, along with IgE production and mast cell activity, while progesterone tends to promote immune tolerance (Valerieva et al., Frontiers in Allergy, 2026). In cultured mast cells, estradiol increased the release of mediators when IgE was engaged, and it raised the number of IgE receptors on the cell surface, effectively lowering the threshold for a response (Hernández Bello et al., Frontiers in Allergy, 2025; Zierau et al., Frontiers in Immunology, 2012).

Testosterone. Androgens appear to work in the opposite direction. They are broadly immunosuppressive, dampening Th2 activity and supporting regulatory T cells, which help keep immune responses in check (Hernández Bello et al., 2025). In mice, male sex hormones reduced the number of group 2 innate lymphoid cells, immune cells that help drive allergic airway inflammation, and males showed less airway inflammation in response to environmental allergens (Laffont et al., Journal of Experimental Medicine, 2017). In a small human study of 78 people, women with allergic rhinitis or asthma had significantly lower testosterone levels than women without allergic disease (Lokaj Berisha et al., Scientific Reports, 2021).

What is not yet known. Together, these findings make hormones a strong candidate for explaining the adolescent shift. They do not yet show that a given hormone level produces a given IgE response to pollen in a given person. Reviewers describe the human evidence as incomplete and at times contradictory; estrogen, for example, also supports regulatory cells that can calm allergic responses (Hernández Bello et al., 2025). Testing that link directly in people is the work still ahead.

The menstrual cycle. Most cycle research has focused on asthma, a closely related condition. Around 30% to 40% of women with asthma report symptoms worsening in the days around menstruation (Zierau et al., 2012).

Menopause. The evidence is mixed. Researchers have not reached a consistent conclusion about how allergic rhinitis changes after menopause, and diagnosis is complicated by overlap with nonallergic rhinitis and other conditions. Hormone therapy has been associated with increased rhinitis symptoms, particularly the nonallergic kind (Valerieva et al., 2026).

Age

Among U.S. adults, diagnosed seasonal allergy was reported by 24.7% of people aged 18 to 44, 27.9% of those aged 45 to 64, 26.4% of those aged 65 to 74 and 21.7% of those 75 and older (Ng and Boersma, NCHS, 2023). Seasonal allergies are not only a childhood condition. They remain common through midlife and into the later decades.

Longer seasons

The season itself is changing. An analysis of North American pollen records from 1990 to 2018 found that pollen seasons began about 20 days earlier, lasted about 8 days longer and carried about 21% more pollen. The researchers identified climate change as the dominant driver of the longer seasons (Anderegg et al., Proceedings of the National Academy of Sciences, 2021).

Why this matters to us

ALTA ORLA formulates for people who spend time outside. Understanding who is affected by pollen season, and how differently, shapes how we think about hair, routine and the days between washes. It does not change what our products are: haircare.

ALTA ORLA products are not intended to diagnose, treat or prevent allergies. If pollen season is difficult for you, talk to your doctor.

This article is educational. ALTA ORLA makes haircare, not medicine. Nothing here describes an effect of our products, and questions about your own health belong with your doctor.

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Sources

• Ng AE, Boersma P. Diagnosed Allergic Conditions in Adults: United States, 2021. NCHS Data Brief No. 460, January 2023
• Zablotsky B, Black LI, Akinbami LJ. Diagnosed Allergic Conditions in Children Aged 0 to 17 Years: United States, 2021. NCHS Data Brief No. 459, January 2023
• Pinart M, Keller T, Reich A, Fröhlich M, Cabieses B, Hohmann C, Postma DS, Bousquet J, Antó JM, Keil T. Sex Related Allergic Rhinitis Prevalence Switch from Childhood to Adulthood: A Systematic Review and Meta Analysis. International Archives of Allergy and Immunology, 2017;172(4):224 to 235
• Fröhlich M, Pinart M, Keller T, et al. Is there a sex shift in prevalence of allergic rhinitis and comorbid asthma from childhood to adulthood? A meta analysis. Clinical and Translational Allergy, 2017;7:44
• Hernández Bello J, et al. Sex hormones and allergies: exploring the gender differences in immune responses. Frontiers in Allergy, 2025
• Lokaj Berisha V, Gacaferri Lumezi B, Berisha N. Low serum levels of dehydroepiandrosterone sulfate and testosterone in Albanian female patients with allergic disease. Scientific Reports, 2021
• Valerieva A, et al. Women hormones and hypersensitivity: allergic diseases in menopause. Frontiers in Allergy, 2026
• Zierau O, Zenclussen AC, Jensen F. Role of female sex hormones, estradiol and progesterone, in mast cell behavior. Frontiers in Immunology, 2012;3:169
• Laffont S, Blanquart E, Savignac M, et al. Androgen signaling negatively controls group 2 innate lymphoid cells. Journal of Experimental Medicine, 2017;214(6):1581
• Anderegg WRL, et al. Anthropogenic climate change is worsening North American pollen seasons. Proceedings of the National Academy of Sciences, 2021;118(7):e2013284118