Why Perimenopause Can Feel Like an Allergic Reaction
If I was to ask you about histamine, chances are you’ll respond with….. “Oh not an issue for me. I don’t have hayfever or allergies?”
But if you have entered your 40’s and all of a sudden things like night sweats, anxiety, heavy periods, migraines or a period flu have entered the chat, chances are we need to chat about histamine.
In clinic, I see this pattern constantly. A woman comes to me convinced her hormones are simply "unbalanced," and while that's often true, what's actually driving a lot of her symptoms is an oestrogen and histamine loop that nobody filled her in on. A loop that I am all too familiar with (ask me how I know).
And when it comes to this loop, perimenopause isn't a slow decline. It's a rollercoaster….I know, I know like we needed more to think about in our 40’s.
Most women assume perimenopause means oestrogen is quietly dropping off. In reality, especially in the earlier years, oestrogen doesn't decline in a straight line at all. It swings, often climbing well above what's considered a normal premenopausal level, before crashing down at the end of each cycle (feels rather dramatic doesn’t it).
It’s this steep drop at the end of your cycle thats part of why some of your perimenopause symptoms (the anxiety, the brain fog, the sleep disruption) can feel so intense. But the spikes matter just as much as the crashes, because those spikes are what set off the histamine response.
The oestrogen and histamine connection
I’ve spoken about this in the past in particular with the neurodivergent brain and nervous system (check out this article), but it’s important to understand that histamine isn't only involved in allergies and hayfever. It's a stimulating neurotransmitter, which is part of why antihistamines make people drowsy. When histamine is elevated, we can often feel more awake but not in a good way, more an agitated, wired but tired can't-switch-off kind of way. It can also show up as feeling like you keep getting a cold/flu around ovulation or your period (also known as a period flu). You might get headaches or migraines or just feel down. Feeling like you have a foggy head or trouble with cognition. Feeling almost blurry? Thats all signs your histamine is off the rails too.
So whats happening here?
Higher oestrogen increases histamine in a few different ways. It activates mast cells (the immune cells that store and release histamine), it increases the enzyme that converts histidine into histamine, and it reduces the activity of DAO, the enzyme responsible for clearing histamine out of the body. At the same time, histamine stimulates the ovaries to produce more oestrogen, which is how this can turn into a feedback loop no one asked for instead of a one-off flare.
To make things more complicated, progesterone is usually the first hormone to decline in perimenopause, and progesterone is one of the body's natural mast cell stabilisers. Losing it early means losing some of your natural protection against histamine build-up, right at the point when oestrogen swings are asking more from you.
Why "too much histamine in" isn't the whole story
Histamine levels come down to a balance between how much your body is making and how well it's clearing it. When that balance tips, either because there's too much going in or too little coming out, symptoms start to show up.
On the "too much in" side, the main drivers are mast cell activation from inflammation, alcohol or food sensitivities (dairy is a common one), naturally histamine-rich foods, and gut dysbiosis, since certain gut bacteria produce histamine themselves. Oestrogen excess adds to this load by activating mast cells directly.
On the "not enough clearance" side, the main drivers are a genetic tendency toward slower histamine-clearing enzymes, small intestinal bacterial overgrowth (SIBO), low vitamin B6 (an essential cofactor for clearing histamine), oestrogen excess again (this time by slowing the clearance enzyme rather than just increasing production), and low progesterone. The pill can make things worse since it tends to create both oestrogen excess and progesterone deficiency at once.
So many of these symptoms can be filed under "oestrogen dominance" but really what we are looking at is this loop. The same mechanism turns up in conditions like endometriosis, PMDD and heavy menstrual bleeding, not just perimenopause.
What high histamine can look like
Because the symptom picture overlaps so heavily with "typical" perimenopause presentations, high histamine is easy to miss and it can be misdiagosed as a different hormone issue. Often, it shows up as:
Hives or unexplained skin reactions
Fluid retention
Ringing in the ears
Anxiety or a wired, agitated feeling
Trouble sleeping, even when you're exhausted
Brain fog
Headaches or migraines, particularly around ovulation or before a period
Breast tenderness
Feeling stuffy and blocked up.
A cold/flu like symptom around ovulation or your period.
It's important to understand, none of these symptoms are only caused by histamine. But if you've addressed the obvious diet and lifestyle factors and you're still struggling, it's worth asking whether histamine is part of what's going on underneath. I often find it is.
The reason being, gut health is a big issue in the world we live in. Dysbiosis and DAO deficiency combines with a sluggish liver detoxification process, whether that be phase 1 or phase 2. Stress, which makes everything worse. Medications. Undereating. Dieting constantly and jumping from one thing to the next. All of this will pull the trigger on the histamine loop, especially in your 40s.
What this means for treatment
This is exactly why "just balance your hormones" is not going to work. How on earth is one supposed to just “balance their hormones”. Run for the hills if this is the only advice being given (especially if its tied to someone trying to sell you a magical product that will fix everything). Its way too vague to be useful advice. If high histamine is part of your picture, the approach needs to include supporting how your body clears and regulates histamine, not only managing oestrogen and progesterone in isolation.
In practice, this can involve several layers working together:
Gut health first. Underlying dysbiosis or SIBO can quietly drive histamine production and impair clearance, so this is often the foundation rather than an afterthought.
We might also need to address a potential DAO deficiency and make you have enough. DAO is the enzyme that breaks down dietary histamine in the gut, so low levels mean histamine accumulates.
Vitamin B6. As a key cofactor for the enzyme that clears histamine, B6 is one of the more underrated tools here, and it supports calming neurotransmitters at the same time.
Bitter foods and herbs. Coffee, cruciferous vegetables, dandelion root, milk thistle and berberine can help stabilise mast cells.
A short-term trial of lower-histamine eating. Reducing high-histamine foods like alcohol, aged cheese, cured meats and fermented foods can offer clarity while the underlying drivers are being addressed, though long-term restriction usually isn't necessary once gut health improves.
Supporting methylation, which helps the body clear histamine more efficiently.
Body-identical progesterone, where appropriate, given its natural antihistamine and mast-cell-stabilising effect.
Making sure oestrogen is being cleared properly, that your detoxification pathways are doing their job. I have a few tools in my kit when it comes to achieving this.
Honestly, there is enough going on as a woman, especially in perimenopause, without being on the histamine-oestrogen merry go round. Lets get you off this wild ride. To do this, we must stop accepting that all of these symptoms are just part of ageing. Part of perimenopause. Menopause is not a disease, BUT it will be pretty disruptive if we don't address some of the main things that can cause drama. This loop is one of those things. It's linked to gut health, stress, liver function, diet.....and often it will have been festering away for a decade or so before you feel the impact.
What I would like you to take away from this article is this. None of this is permanent. It just requires understanding what's actually driving it, and a plan that addresses the right layer and works with you as a whole person.
This is the kind of layered, physiology-first thinking I bring into an Initial Naturopathic Consultation. Rather than treating "perimenopause" as one generic diagnosis, we look at what's actually driving your specific symptoms, so the plan we build is based on your biochemistry, not a one-size-fits-all approach.
If this article sounds like it could be describing you, it might be time to find out what's really going on underneath the surface. I welcome you to book a discovery call HERE, or if you're like, "No Carolyn, I already know this is what's happening and I need to jump off the merry go round," book your Initial Naturopathic Consultation HERE. I see clients from all over Australia online via Zoom. And if you're in Noosa on the Sunshine Coast and prefer a face to face appointment, I practice out of the Noosa Wellness Collective every single Friday.
So book HEREor reach out with questions. This is the kind of work I find most meaningful because understanding changes everything.
Carolyn Allen is a naturopath and yoga therapist specialising in women's hormonal health in perimenopause and beyond. She works with women across Australia via online consultations from her practice in Maleny, Queensland. She also sees clients in Noosa at the Noosa Wellness Collective. To enquire about comprehensive functional testing like gut, DNA or hormone testing, results interpretation, and personalised support, visit carolynallenhealth.com or email hello@carolynallenhealth.com
This article is written for educational purposes and does not constitute individual medical advice. Please work with a qualified practitioner for personalised assessment and treatment.