Allergy · ALEX3 Testing

Hay Fever or Allergy? How to Tell the Difference

Dr Raj Dhillon  ·  September 2026  ·  5 min read

Hay fever is a form of allergy — specifically, an allergy to grass and tree pollen that causes seasonal symptoms in spring and summer. But not all "hay fever" is pollen allergy, and not all year-round nasal symptoms are hay fever. Getting the distinction right changes how you treat it.

Seasonal vs Perennial: The Key Distinction

Hay Fever (Seasonal)Perennial Allergic Rhinitis
TimingSpring/summer (March–August in UK)Year-round — or worst in autumn/winter
TriggersGrass pollen, tree pollen, mould sporesHouse dust mites, pet dander, mould
Worst time of dayMorning and evening (when pollen counts peak)First thing in the morning, on waking
Symptoms better when?Indoors, air-conditioned, in cities, on rainy daysOutside and away from the home/triggering environment
Duration without treatmentLasts weeks (during pollen season)Constant, year-round
Common in childrenYes — begins in childhood typicallyYes — often co-exists with eczema

The Warning Signs It's Not Just Hay Fever

House dust mites are the most common cause of year-round allergic rhinitis in the UK. They live in bedding, carpets, and soft furnishings — which is why symptoms are worst on waking and improve after leaving the house.

Why Getting the Right Diagnosis Matters

If you're treating grass pollen allergy but your actual trigger is house dust mite, antihistamines and pollen-based avoidance strategies will give you partial relief at best. The treatment strategy differs significantly:

How Allergy Testing Gives You the Answer

The ALEX3 allergy blood test analyses IgE antibodies to over 300 allergens from a single blood draw — including all UK-relevant pollens, house dust mite species, pet danders, moulds, and foods. Results are returned as a detailed allergen profile showing which specific substances you're sensitised to and the strength of each reaction.

This takes the guesswork out completely. Instead of trialling treatments and noticing which ones do something, you start with a precise picture of what your immune system is reacting to.

ALEX3 Allergy Testing in Surbiton

One blood draw. 300+ allergens tested. Results within days. Book your ALEX3 allergy test at Lambert Medical Practice.

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