The Big 3 Seasonal Hay Fever Triggers; Pollen, Phenolics and Terpenes

Spring has arrived, and along with it hay fever, which affects 1 in 5 Australians and New Zealanders. This number is ever increasing due to higher stress levels, impaired gut health and climate change. In this article, learn more about the big 3 seasonal hay fever triggers; pollen, phenolics and terpenes.

These airborne triggers are commonly part of a Positive Association Technique (PAT) treatment plan for seasonal hay fever symptoms.

What is hay fever?

Firstly, hay fever has nothing to do with hay and hardly ever has the symptom of fever!  

Hay fever refers to the ‘haying season’ which happens in the spring months when farmers harvest and bale hay. This can cause high amounts of allergenic triggers to go into the air causing a reaction for some people. Hay fever doesn’t cause a fever but you can have a redness in the face from irritation of your symptoms, so you may look like you do even though your body temperature is in normal range.

Hay fever is also called “allergic rhinitis” and there are two different types;

Firstly, Seasonal allergic rhinitis only occurs during the time of year when plants pollinate and is caused by wind-borne pollen and other seasonal hay fever triggers.

The most problematic pollen is produced from trees, grasses and weeds as these are generally lightweight and spread easily by the wind. They are able to be transported very long distances and can cause adverse reactions in people living a long way from their source. 

The pollen from showy flowers are generally very heavy and sticky and require a pollinator (such as bees) to carry the pollen from one flower to another and so  are less likely to cause seasonal allergies. The exact period that someone reacts depends on what plants the person is allergic to.  In springtime many people react to the flowering trees, in summertime it is more the grass and weed pollens.

Secondly, perennial allergic rhinitis can occur all year round as it is caused more by indoor allergens like dust mites, mould and animal dander from pets.

What causes seasonal hay fever?

Hay fever occurs when the immune system overreacts. When you encounter an allergen, your immune system treats it like an intruder and releases chemicals like histamines, leukotrienes and prostaglandins.

This leads to inflamation the lining of your nasal passages, sinus and eyelids which cause the symptoms of runny nose, itchy watery eyes, itchy mouth throat or ears, post nasal drip, pain or pressure around your sinuses sneezing and coughing. All these symptoms are meant to protect your body by either trapping or expelling the allergen or swelling body areas like the nasal passages so the allergen can’t enter.

If you have perennial allergic rhinitis these symptoms can be all year round. The swelling of your nasal membranes may also close the sinus drainage openings causing sinusitis. Nose bleeds can also occur during a reaction or if you have asthma it can exacerbate it and you can have trouble breathing. 

Fatigue is often the most debilitating part of hay fever, it can feel as though you have a cold or a flu.  For those of you who don’t react, spare a thought for your friends and family as it really affects their quality of life, it can change their mood, affect their sleep and make it harder to focus and the symptoms can happen daily during the spring/summer season!  

The frustrating thing for hay fever sufferers is that these substances are harmless and don’t affect other people. Most people have no immune response to pollen but for some their immune systems perceive it as foreign and dangerous and treat it as if it were a pathogen.

Hay fever is often an inherited trait.  Scientists conducted studies on twins and found that the heritability of hay fever ranges between 33% and 91%. This means that people who have parents or siblings with hay fever have a high chance of getting it themselves.

Scientists also found that asthma and eczema are inherited issues. During these studies they found that 41 genes can lead to hay fever and now DNA tests can identify whether or not your genes could cause you or your children to develop hay fever. 

Why is hay fever becoming more common?

According to the World Health Organization (WHO), climate change is lengthening pollen allergy seasons and increasing the intensity of allergens. Changes in temperature, the weather and Co2 rates have increased the severity and the amount of people who have allergies world wide.

Scientists have discovered that carbon dioxide itself encourages pollen production. Plants thrive in a warm greenhouse with high carbon-dioxide levels and in some cases produce more pollen than they otherwise would which is now happening on a world wide scale, as the world has literally become a greenhouse!

You can read our full blog post all about climate change and allergies HERE.

Australia went through a millennial drought between 2000 and 2010 causing grass levels to be low so less people suffered severe symptoms as they had previously. But from 2012 onwards, Australia began to get more rain and it has dramatically increased grass pollen in the atmosphere which is the major allergen responsible for hay fever in Australia. 

Furthermore, the la Nina weather events from 2020-2023 has contributed to the problem, as it brings more rain, warmth and humidity which creates optimal growing conditions for pollen producing grass, weeds and trees.  Last year Canberra recorded its worst hay fever season on record with the highest rates of hay fever sufferers in the country, with 1 in 3 likely to be affected compared to 1 in 5 nationally.

Modeling suggests that by the end of this century the hay fever season will begin 40 days earlier and finish 15 days later, with much higher rates of pollen in the atmosphere too.

Because there is now more pollen in the air, people who previously didn’t get hay fever are now suffering from it as they have reached a threshold of their tolerance to it. These people didn’t know they had allergies but they do, they just hadn’t been exposed to enough pollen to experience symptoms yet. 

The body reacts when it perceives there is too much and so new people, especially adults are experiencing symptoms for the first time, and others who usually get hay fever are experiencing a worsening of their symptoms and length of time they react.

Climate change has also created a new phenomenon called the ‘priming effect’. A mild winter can trigger an early release of pollen and once allergy sufferers are exposed to this their immune system is primed to react to the allergens, meaning that even if there is a small amount of pollen in the air their body will launch an immune response and cause hay fever symptoms making for a longer hay fever season for them, with stronger symptoms.

Where you grew up can also have a big impact on your susceptibility to hay fever as it depends on what you were exposed to, especially if you move countries.  If you grew up in a dry inland environment you may not have been exposed to much grass pollen, and moving to Australia and New Zealand where grass pollen is one of the leading causes of hay fever can make your immune system susceptible and you may start reacting. 

The same goes for people who have moved from tropical to non tropical countries as they will encounter seasons for the first time and with it new species of pollen that their immune systems have not experienced. 

You don’t have to move to encounter new types of pollen, as the planet warms up opportunistic plants are managing to thrive in areas they normally would not be able to grow, exposing people to new pollens their immune system doesn’t recognise and therefore reacts to.

Other Seasonal Hay Fever Triggers; Phenolics and Terpenes

While pollen may be the most prevalent hay fever trigger, there are a couple of other plant metabolites that can contribute to hay fever symptoms as well that are not so well known; plant phenolics and terpenes.

Plant phenolics are naturally occurring chemicals in all plants that are responsible for taste, color and smell. They also play a major role in defending the plant against pests and pathogens. Whenever you mow your grass, cut or prune a tree the plants will release these chemicals in defense which can cause hay fever, asthma or skin conditions in some people. Plant phenolics are why some people get itchy sitting on cut grass but are okay when it hasn’t been mowed. 

They are also the way plants communicate and defend against other plants, as they can release specific biomolecules that can create a barren space around them that no other plant can thrive in to allow their species more growth. This is termed ‘allelopathy’ and they are potent chemicals that some people react to. Climate change may also be playing a role in an increase in these interactions, with plants releasing more phenolics in the environment, causing an increase in phenolic related allergies. 

Terpenes are aromatic compounds that determine the smell of many plants and herbs like rosemary, lavender and pine. They play a vital role in plants attracting pollinators or repelling insects and animals. Some play a protective role in the plant helping it to recover from damage, or as part of its immune system. They were first identified in the 19th century and got their name from turpentine, a product made from pine tree resin that is rich in the terpene known as pinene. 

Terpene sensitivity or allergy occurs when terpenes are inhaled or applied to the skin. When this happens, antibodies are produced. This process then activates the production of chemicals that trigger hay fever symptoms like sneezing, runny nose, watery eyes, inflammation, and coughing.

Terpenes themselves are not allergenic, they only cause allergies when oxidized when or exposed to air. Some studies show that oxidized terpenes can trigger asthma and rhinitis in certain people. In particular, inhalation of pinene from a pine tree has been found to cause respiratory symptoms and nasal congestion. This is why some people react when they walk into a house with a freshly cut Christmas tree or live near a pine plantation.

They can also cause contact dermatitis as manufactures use isolated terpenes to create flavors and scents in perfumes, body products, and even foods. Reactions have been dated back from the early part of the 20th century where painters were recorded getting occupation contact dermatitis from the use of turpentine as a solvent to dissolve paints and varnishes.

The Hygiene Hypothesis

All allergic conditions, not just hay fever, have become much more common over the last few decades and there are a couple of theories being researched to explain why this is happening; the ‘hygiene hypothesis‘ and low vitamin D levels.

The ‘hygiene hypothesis’ is the idea that more developed countries are too clean, and so children are not being exposed to micro-organisms which protects them against allergies by strengthening the immune system. Exposure to parasites and bacteria is what trained the immune system to be so effective, it has evolved over millions of years and is used to being under constant threat, but now as it has less to do it can overreact and become aggravated by harmless substances like pollen or dust mites and interprets them as bacterial invasions and tries to expel them.  

Low vitamin D levels may also be contributing to the rise of allergies as scientific evidence has shown that food allergies and anaphylaxis occur at much higher rates in areas where there is much less sun exposure. Asthma, eczema and atopy (an exaggerated IgE mediated immune response) have been associated with low vitamin D levels.  Many studies suggest that vitamin D deficiency is very common, even in Australia where there is lots of sun.

In recent years, COVID and a increased rainfall has kept people indoors more, and since vitamin D is made in the skin with sunlight exposure, covering up or using sunscreen when outside prevented vitamin D synthesis. 

Vitamin D can activate certain regulatory immune  system cells that prevent the release of chemicals that cause and worsen allergies, so deficiency may inhibit this regulatory mechanism, which may worsen or trigger an allergic disease.

Why do anti-histamines stop working?

Hay fever sufferers traditional way of combating it is with the use of antihistamines, which essentially stops the body releasing histamine reducing their symptoms. But unfortunately, when these medications are taken over a long period of time they can stop being as effective because the body has developed a tolerance to the drug. 

This can happen when the body’s cells become less responsive to a drug the longer it is exposed to it, like how the taste receptors on your tongue adapt to extra spicy foods when eaten often, termed ‘dynamic tolerance’. The body can also start to respond to the ongoing presence of a drug and begin to break it down and excrete it more actively, lowering the drug concentration, termed ‘kinetic tolerance’.

Also, when your stress levels increase, antihistamines may have a weakened effect and provide less relief than in less stressed periods (1). This is because long term stress disrupts your immune system and worsens allergies by increasing sensitivity to them, as mental or emotional stress can cause mast cell deregulation which releases inflammatory mediators that can cause airway constriction, increased mucus production, coughing and sneezing, hives and other symptoms associated with hay fever and allergies.

Natural Hay Fever Treatment

At Health & Wellness Australia & Auckland (HWA), we use a technique called muscle testing (or kinesiology) to help identify reactions to pollen, phenolics, terpenes, grasses and trees.

Following testing, you can work with your qualified Naturopath to address the reactions to these airborne triggers using a natural allergy treatment called Positive Association Technique (PAT).

We have clinics located all over Australia and in Auckland, New Zealand, and help thousands of people relief their hay fever symptoms each year.

To find out more about how we can help you, get in touch!

• Call us on 1300 853 023 / 09 479 5997 (NZ) to chat to our friendly staff
• Send us your question HERE
• Request a Free PAT Information E-PACK HERE

---

---

Please note that this blog post contains general information only. Always consult your health care professional before changing your diet, starting new supplements or regarding any medical condition.