Hay Fever & Seasonal Allergies
Why Symptoms Can Be So Intense – And How the Gut, Immune System, Hormones and Nervous System Are Involved
Bay Functional Health | Tauranga Naturopaths Lisa & Paige
In the Bay of Plenty, hay fever season can feel relentless. This season has been one of the worst I have seen symptom wise.
We hear you when you tell us:
“My nose never stops running.”
“My eyes itch and burn.”
“I’m constantly sneezing.”
“My head feels full and heavy.”
“I’m exhausted and foggy.”
“My throat is itchy.”
“My sinuses feel blocked or inflamed.”
“I can’t sleep properly.”
“My skin is reactive.”
“Antihistamines help a bit, but I still don’t feel right.”
From a functional perspective, hay fever is not just about pollen.
It’s about immune sensitivity, histamine load, gut health and nervous system reactivity.
Common questions we are asked:
“Why is my hay fever so bad this year?”
“Natural treatment for hay fever”
“Histamine and allergies”
“Gut health and hay fever”
“Why do antihistamines stop working?”
“Hay fever and fatigue”
“Hay fever and brain fog”
Histamine is the chemical that drives sneezing, itching, runny nose, watery eyes and swelling. But histamine also acts as a neurotransmitter in the brain, which is why hay fever can come with anxiety, poor sleep, irritability and that wired, inflamed feeling.
The immune system
Allergic reactions reflect an immune system that is over-responding to otherwise harmless triggers. Chronic stress, nutrient depletion, post-viral states and ongoing inflammation can all increase this sensitivity.
The gut–immune axis
Around 70% of the immune system is regulated through the gut. Dysbiosis, leaky gut, SIBO, constipation and poor microbial diversity can all skew immune signalling toward allergy and inflammation, increasing histamine release and reducing tolerance to environmental allergens.
Histamine breakdown (DAO enzyme)
Histamine is normally broken down by an enzyme called DAO, produced in the gut lining. When the gut is inflamed or under-functioning, DAO levels drop, and histamine accumulates. This means pollen exposure plus dietary histamine plus internal histamine release can overwhelm the system.
Hormones and perimenopause
Oestrogen increases histamine release and reduces its breakdown. This is why many women notice hay fever worsening in perimenopause, during certain phases of the cycle, or when hormone balance shifts.
The nervous system
A nervous system in chronic fight-or-flight becomes more reactive to sensory input, including allergens. Stress, poor sleep and burnout lower the threshold for immune activation and intensify symptoms.
Nutrient foundations
Healthy immune regulation and histamine clearance rely on:
• Vitamin C (histamine degradation, mast cell stability)
• Vitamin B6 (DAO production)
• Zinc (immune balance, tissue repair)
• Copper (DAO activity)
• Magnesium (nervous system calming, inflammation modulation)
• Vitamin D (immune tolerance)
• Quercetin and bioflavonoids (mast cell stabilisation)
Why antihistamines aren’t always enough
Antihistamines block histamine receptors but don’t address why histamine is high in the first place:
• Gut permeability
• Dysbiosis
• Hormonal shifts
• Nutrient depletion
• Stress and cortisol dysregulation
• Post-viral immune priming
• Environmental load
At Bay Functional Health, we look beyond symptom suppression and support the systems that regulate immune tolerance.
Lisa supports:
• Nervous system regulation
• Histamine and inflammatory patterns
• Hormonal transitions and perimenopause
• Sleep and cortisol rhythm
• Post-viral immune recovery
Paige supports:
• Gut health and microbiome balance
• Motility and constipation
• Gut–immune signalling
• Nutrient uptake
Hay fever isn’t “just seasonal.”
It’s a reflection of how sensitised the system has become.
When the gut barrier is strengthened, histamine clearance improves, the nervous system calms and immune tolerance is restored, seasonal symptoms often soften significantly.
Lisa & Paige
