Suddenly Allergic to Dust or Pollen? Perimenopause May Be Rewiring Your Immune System
Imagine going most of your life without so much as the annual cold, only to develop recurrent sinus infections and allergies at 52. That’s exactly what happened to Hilary Morse (now 56).
“When I say I don't get sick, I don't get sick,” says the Los Angeles-based publicist. That all changed when she went to the doctor with a severe sinus infection. After extensive testing by an allergist, she learned she had a dust-mite sensitivity, which seemed to explain why she now felt itchy and congested in nearly every room she walked into. One doctor suggested she might be reacting to lingering environmental irritants from the Los Angeles wildfires. Another ENT discussed sinus surgery because her symptoms had become so severe.
Nothing was adding up until, after two years of dealing with these newfound health issues, Morse was chatting with a friend during a ski trip. “I think it's menopause,” her friend told her. “I went through over a year of the same stuff.”
That conversation prompted Morse to get blood work to see whether she had entered menopause. The results revealed she was already postmenopausal.
“I don't know when I started perimenopause because I was on birth control pills, and I had switched to the Mirena IUD, so I didn't ever get a period. And I didn't have hot flashes. I didn't have weight gain. I didn't have anything,” Morse recalls.
As it turns out, her experience may not be a coincidence. A growing body of research suggests that something much bigger may be happening beneath the surface during the menopausal transition. As estrogen and progesterone fluctuate, the immune system appears to shift alongside them, potentially changing how the body responds to everything from environmental allergens and asthma triggers to histamine itself.
“Many women report new or worsening allergy-like symptoms during this transition, and while we still need more research, these findings reinforce that menopause affects far more than just reproductive health,” says Mary Claire Haver, MD, a board-certified OB-GYN and certified menopause specialist.
How Menopause May Influence the Immune System
The recent review published in Frontiers in Allergy took a deep dive into emerging research on menopause and allergy-related conditions, including asthma, allergic rhinitis, eczema, and drug hypersensitivity. While the authors acknowledge “significant knowledge gaps,” and that the studies they reviewed are largely anecdotal or derived from small cohorts, there’s still sufficient evidence to suggest that hormonal changes can influence immune function.
“We've known for a long time that estrogen modulates all these different parts of our immune system,” says Gillian Goddard, MD, an endocrinologist, adjunct assistant professor of medicine at NYU Grossman School of Medicine, and author of The Hormone Loop. “There's almost no part of our immune system that is untouched by estrogen.”
Estrogen does far more than drive your menstrual cycle during your reproductive years—it helps regulate immune cells throughout your body. During perimenopause, your estrogen levels can spike to some of the highest levels a woman experiences outside of pregnancy before dropping sharply again—sometimes multiple times in a single day, Goddard notes.
“Menopause is not just a transition in reproduction; it's a transition in your immune system. —Zachary Rubin, MD, allergist-immunologist”
“It's not just that the estrogen modulates the immune system; it's turning things off and on, and it's almost like the signals get crossed,” she says. She equates this process to an old-fashioned telephone switchboard. As connections are constantly plugged in and unplugged, signals can become crossed.
During perimenopause, these rapid hormonal shifts can make it harder for your body's various systems, including the immune system, to communicate and function as smoothly as they once did. “Estrogen levels are going up and down so much that it's almost like the cells can't turn off and on in the right sequence in the right way,” Goddard explains.
That concept resonates with Zachary Rubin, MD, a double board-certified pediatrician and allergist-immunologist and author of All About Allergies. “Menopause is not just a transition in reproduction; it's a transition in your immune system,” he says.
How Hormones Affect Histamine
Most people think of histamine as the chemical behind classic allergy symptoms, but it also plays a role in a surprising range of functions throughout the body, including sleep, hunger, cognition, wakefulness, and stomach acid production, Rubin explains.
“Histamine is known to act as a neurotransmitter with neuropsychiatric effects on mood, cognition, and anxiety,” says Charis Chambers, MD, FACOG, a board-certified OB-GYN, chief medical officer of Clue, and author of The Period & Puberty Parenting Revolution.
Histamine is like a helicopter parent—in the case of allergies, it often overreacts to harmless triggers like pollen, dust, and other common allergens. When this chemical is released, it leads to classic allergy symptoms. Think: sneezing, itching, congestion, and hives.
Histamine is stored inside immune cells called mast cells, which act as some of the body's first responders to potential threats. When activated, mast cells release histamine into the body—and estrogen is one of the signals that can prompt that release, Rubin says. “We know that estrogen can influence histamine activity, and histamine can, in turn, affect hormone signaling, which may help explain why some women notice changes in mood, allergy symptoms, migraines, or other symptoms during times of hormonal fluctuation,” says Haver.
“Estrogen can influence histamine activity, and histamine can, in turn, affect hormone signaling, which may help explain why some women notice changes in mood, allergy symptoms, migraines, or other symptoms during times of hormonal fluctuation —Mary Claire Haver, MD, board-certified OB-GYN”
Fluctuating estrogen levels can also affect how mast cells behave, says Louise Newson, a physician and hormone specialist in the United Kingdom and author of The Power of Hormones. As hormone levels change, mast cells may become dysregulated and release more histamine than they otherwise would.
“Progesterone and testosterone play important roles in helping stabilize mast cells and dampen down histamine, so when our body has low levels of estrogen and progesterone, this can lead to more severe allergic reactions and asthma—and even lead to new allergies developing,” Newson says.
That means women in perimenopause aren’t the only ones impacted. For example, histamine can worsen symptoms of PMS and premenstrual dysphoric disorder (PMDD)—an often debilitating form of PMS characterized by mood changes in the late luteal phase of the menstrual cycle, Chambers explains. During this phase, both progesterone and estrogen decrease just before your period, which in some people can trigger an uptick in histamine activity.
The hormone-histamine connection is behind the recent online chatter about women using a combination of Allegra and Pepcid AC—over-the-counter antihistamines—to ease symptoms like brain fog associated with both PMDD and menopause.
Allegra blocks one type of histamine receptor associated with classic allergy symptoms, while Pepcid AC blocks a different histamine receptor best known for regulating stomach acid, Rubin explains. Together, the two may help dampen histamine signaling through multiple pathways—however, that remains anecdotal for now.
“There are to date no clinical trials or guideline recommendations to support use of Allegra or Pepcid specifically for PMS or PMDD or for peri/menopause brain fog,” says Alyssa Dweck, MD, FACOG, chief medical officer of Bonafide Health and a Menopause Society Certified Practitioner.
What to Do If You Suddenly Develop Allergy Symptoms
If you're suddenly dealing with new allergies, eczema flare-ups, and sinus issues in midlife—especially if you’ve never had allergies before—reaching for over-the-counter-meds may be a bandaid, not a solution to the main problem. That’s why it’s important to track your symptoms, look for patterns, and discuss them with both your primary care provider and a menopause specialist when possible.
For some women, addressing underlying hormonal changes may be the answer. After starting hormone replacement therapy, for example, Morse says the recurrent sinus infections and allergy symptoms she'd battled for two years completely disappeared.
But Goddard cautions against looking for a single “fix.” Perimenopause is a natural biological transition, and “the process is the process,” she notes. The goal isn't necessarily to stop these hormonal changes, but to manage your symptoms so you can feel and function at your best.
We still have a long way to go in terms of research. “We're in the early stages of understanding how the endocrine system and immune system interact,” says Rubin. “Hopefully, what we're talking about right now opens the door for more investigative studies and more conversations [that lead to] better treatments in the future.”