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Do pollen allergies cause anxiety?

Feeling anxious?

You’re not alone.

The NY Times ran a story about a year ago titled “Prozac nation is now the United States of Xanax.”

Why is everyone anxious? If you believe, as I do, that anxiety is a symptom, not an identity, there are lots of potential reasons, many of which are work stress related. Constantly checking email for news of a fire drill at work will put anyone in a state of anxiety.

Allergy and mental health

But today I want to focus on a lesser known cause of anxiety, which is seasonal allergies.

When you think of allergy, you probably think of itchy, watery eyes and sneezing, maybe a cough. You don’t think of mental health. But living in an environment with multiple allergy triggers can cause anxiety.

For those of you who regularly read the blog, you know I’ve been writing a lot lately about histamine, a topic that first came on my radar after having a rough allergy season when living in Austin (I have since moved, 100% because the allergies are so severe there for me that I simply cannot live there).

You can read my histamine intolerance post here, but the bottom line is that pollen allergy, or any other seasonal allergy, can cause mental unrest when it’s paired with other factors that cause histamine to build up to excessive levels in the body, or when the allergy is severe enough on its own to cause histamine overload.

In my case, I had some allergy tests done and found that I have some major allergies to central Texas grasses, like Timothy and Bermuda grass. When the grass was in full swing a few months ago, I would wake up feeling unusually scattered and on edge. When I went to California, as I do often, I experienced a total abatement of symptoms.

Total Zen mode, relatively speaking.

This began to fascinate me. Why was I calmer in San Diego?

I’m sure there were a few factors at play, but one was certainly allergy related. There is nothing I am allergic to in San Diego.

The whole experience of living in Texas, and the utter pain the environment visited upon me, was so odd, I felt compelled to write this post for what I imagine is a large group of people who would be better off taking a Zyrtec, or a whole bunch of vitamin C (has been shown to clear histamine), than they would a benzodiazepine.

Allergies can contribute to anxiety

I wouldn’t go as far as to say that pollen allergies cause anxiety. I think it’s more accurate to say that they contribute to anxiety. For most people, normal airborne allergens alone won’t be enough to cause severe anxiety symptoms. It’s likely you’ll need to add to the equation reduced genetic ability to clear histamine, a diet of at least some histamine rich foods, or compromised gut health, so the issue, like most, is multifactorial.

Having said that, if any one of the following four factors are particularly strong, that factor alone could be causing your anxiety.

  • Allergens12
  • Histamine Genes
  • Compromised gut health plus histamine rich food

Let me explain.

Histamine affects the central nervous system

People forget that histamine, the stuff your immune cells release when they perceive a threat (and if you have allergies, pollen is a threat), is a neurotransmitter.

It is responsible for cell to cell communication, sending signals that impact sleep, body temperature, cardiovascular signals, food intake, memory and much more.3

Simply put, histamine affects the central nervous system and anxiety is one of the tell tale symptoms of histamine intolerance. The equation is relatively simple: as histamine levels rise beyond what your body can effectively clear, symptoms like anxiety can rear their ugly head.

The histamine genes

We screen for both of these genes as part of assigning a histamine score to our custom nutrition plan customers.


The terminating enzyme for histamine clearance is called histamine-N-methyltransferase and its job is to clear intracellular histamine as well as histamine in the brain.4 Not everyone has the same ability to clear histamine. HNMT levels can vary by as much as 5 times between individuals based on genetics.56


Diamine oxidase (DAO) is another enzyme I’ve written about lately. DAO is found in largest concentrations in the gut and its job is to clear extracellular, or free floating histamine. Like HNMT, variants in the AOC1 gene (the gene that is coded to make DAO) have been associated with varying levels of DAO. Lifestyle decisions can also reduce DAO. NSAIDs, antibiotics, and alcohol are some of the biggest culprits for reducing DAO levels.

If you have reduced genetic ability to clear histamine, or you’ve recently taken high dose Ibuprofen or a potent antibiotic, and you live in an environment with multiple allergy triggers, you could be predisposed to anxiety, especially while on a histamine rich diet, and especially during allergy season.

My experience with pollen and anxiety

I eluded to this above, but my personal experience is that I feel calmer in coastal cities, especially in California (kind of hard to go into Zen mode in NYC). I don’t have many HNMT SNPs but I do have a relevant AOC1 SNP which is associated with reduced diamine oxidase levels, the enzyme that clears histamine from the gut, and the Texas grass is what seemed to push me into symptom range all on its own.

Note: I have never had my serum diamine oxidase levels tested. My understanding is that it is difficult to find good labs to run this test – which doesn’t mean there aren’t labs that can run a DAO panel, just that it may be tricky to get reliable results.

Note: While most blogs exclusively discuss DAO and HNMT in connection with histamine intolerance, AOC1 and HNMT are not the only genes that affect histamine metabolism. We also include IL-8 and ALDH2 as part of our histamine scoring system.

During spring time, removing myself from environments where severe allergens are present in large amounts, like Austin for example, improves my quality of life.

See also: Why are my allergies so bad in Austin?

Studies linking allergy to anxiety

Think this is all bullshit?

Consider this meta-analysis of studies done on allergy and anxiety /depression that appeared in the Journal of Innovations in Clinical Neuroscience:

Through a review of the relevant articles in the PubMed and PsycINFO databases, the authors found that the majority of studies (9 of 11 studies on anxiety syndromes, 10 of 12 studies on depressive syndromes) indicate associations between allergies and anxiety/mood syndromes, despite a number of methodological variances.

Interestingly, one of the studies included in the meta-analysis found a link between self reported hay fever and panic attacks.7 At first glance, it seems strange, but once you start thinking of histamine as a neurotransmitter that impacts the central nervous system, which it is, it all starts to make sense.

Do you have allergies and anxiety?

Removing yourself from an environment with loads and loads of airborne allergens, or popping some Zyrtec, could be better than Xanax.

Experiments to run:

All subject to the approval of your physician.

  • Zyrtec (start with the lowest possible dose so you can find the minimum effective dose)
  • Try a low histamine diet to see how you feel
  • Try a grain free diet and see how you feel (grains could be creating an environment in your gut that causes bacteria to flourish that produce histamine)
  • Go to the coast for a few days, see how you feel
  • If you haven’t already, find out what you’re allergic to in your area through traditional allergy testing
  • Get your genetic data and check for histamine clearing SNPs

Key takeaways

There is abundant scientific evidence establishing a link between mental health and allergy. so if this is something you are experiencing don’t let someone talk you out of a hard fought insight.

The health and wellness world loves to identify all the foods that can cause inflammation in people, but there is very little attention paid to the myriad ways our ambient air can be a driver of inflammation as well.

John O'Connor

John O'Connor is the founder of Gene Food, host of the Gene Food Podcast and a health coach trained at Duke's Integrative Medicine Program. Read his full bio here.

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