Hay fever and allergic asthma

Hay Fever Tests and Sublingual Immunotherapy: A More Personal Approach to Allergy Care

By Professor Michael Rudenko, Consultant in Allergy and Immunology
London Allergy and Immunology Centre

Sneezing through spring, waking with a blocked nose or avoiding the outdoors when pollen levels rise can make hay fever feel like much more than a minor inconvenience. For some people, itchy eyes, poor sleep and difficulty concentrating return year after year despite antihistamines and nasal sprays. If you also cough, wheeze or feel short of breath, your breathing deserves attention too.

At London Allergy and Immunology Centre, Professor Michael Rudenko assesses the pattern of your symptoms, identifies relevant allergens and discusses a treatment plan tailored to you. For suitable patients, that plan may include allergen immunotherapy delivered as a liquid spray under the tongue.

Is it really hay fever?

Hay fever is allergic rhinitis caused by pollen. Grass pollen often causes symptoms in late spring and summer; tree pollen may cause symptoms earlier in the year. Similar symptoms throughout the year may involve house dust mite or another trigger. A careful history matters: the timing of symptoms, exposure, eye symptoms and any asthma symptoms all help determine which tests are useful. A positive test shows sensitisation, but it only identifies a clinically relevant allergy when it fits your history.

Which hay fever tests might you need?

Skin prick testing checks for an immediate allergic response to selected allergens, commonly including grass and tree pollens and, when appropriate, house dust mite. Results are usually available during the appointment. Specific IgE blood testing can be useful when skin testing is unsuitable or further detail is needed. In selected cases, testing individual allergen components may help distinguish genuine sensitisation from cross-reactivity and guide an immunotherapy decision. Broad panels without a clear clinical question can produce confusing results.

If you have wheeze, cough, chest tightness or breathlessness, the consultation may also include an asthma assessment and appropriate breathing tests. Allergy testing alone does not diagnose asthma.

What can treatment include?

Many people benefit from a combination of practical pollen exposure measures, a correctly used corticosteroid nasal spray, and other symptom-relieving medicines where appropriate. Current ARIA–EAACI guidance continues to place intranasal treatment at the centre of allergic rhinitis care. If symptoms remain troublesome despite suitable treatment, or you want to discuss a treatment directed at the underlying allergy, an immunotherapy assessment may be worthwhile.

How does sublingual spray immunotherapy work?

Sublingual immunotherapy (SLIT) exposes the immune system to carefully prescribed amounts of the allergen through a liquid spray placed under the tongue. Over time, it aims to reduce the allergic response and the burden of symptoms. It is a regular, long-term treatment rather than an instant remedy. A course of at least three years is generally recommended when the aim is a lasting effect. The allergen, formulation, dose and schedule must be selected for the individual; evidence for one liquid preparation should not automatically be assumed to apply to every preparation or mixture.

A 2025 systematic review of randomised studies of a specified liquid SLIT formulation found improvements in allergic rhinoconjunctivitis symptoms and use of symptom medicines compared with placebo. Another 2025 review specifically evaluated a five-grass liquid formulation. These findings support discussing liquid immunotherapy with eligible patients while keeping expectations realistic: benefit varies, and the available evidence is product and allergen specific.

What if I also have allergic asthma?

Hay fever and asthma commonly occur together. Professor Rudenko will consider both your nose and your breathing when assessing treatment. Immunotherapy may be an option for selected people with allergic respiratory disease, but it does not replace prescribed asthma preventer or reliever treatment. Asthma control must be reviewed before starting and throughout a course; uncontrolled or severe asthma can make immunotherapy unsafe. Tell the clinic promptly if your breathing worsens.

Is the treatment safe?

Itching or mild irritation in the mouth or throat can occur, particularly at the beginning. Serious systemic reactions are uncommon but possible. A specialist will review your medical history, asthma control, other medicines and the particular product’s precautions, explain what to do if you become unwell or miss doses, and arrange initiation and follow-up according to the prescribed regimen. Do not begin, restart or alter immunotherapy without your treating team’s instructions.

Could I be suitable?

You may benefit from an assessment if pollen symptoms return each year, interfere with sleep, work or school, remain troublesome despite appropriate medication, or occur alongside possible asthma symptoms. A consultation can establish which allergens actually matter, whether further testing is needed and whether sublingual spray immunotherapy is an appropriate option for you.

Take the next step. Book an allergy and immunology consultation with Professor Michael Rudenko at the London Allergy and Immunology Centre to discuss hay fever testing, allergic asthma assessment and personalised treatment options.

Frequently asked questions

Can a blood test alone tell me what is causing my hay fever?

No. Specific IgE results should be interpreted alongside the timing and pattern of symptoms. A positive result by itself does not prove that an allergen is causing your symptoms.

Will I feel better straight away?

Immunotherapy works gradually. You may still need symptom medicines, especially early in the course or during high-pollen periods. Your specialist will review your progress over time.

Does immunotherapy cure hay fever or asthma?

It can reduce allergic symptoms and medicine use in suitable patients and may have a lasting effect after a completed course, but results vary. It is not a guaranteed cure and should not be used in place of asthma care.

This article is general information and does not replace individual medical advice. Reviewed against research and professional guidance available in September 2026.

Research and guidance

1. EAACI guideline: allergen immunotherapy for allergic rhinoconjunctivitis.
2. Di Bona D et al. Liquid sublingual immunotherapy in allergic rhinoconjunctivitis: systematic review and meta-analysis, 2025.
3. Five-grass pollen liquid sublingual immunotherapy: systematic review and meta-analysis, 2025.
4. BSACI: Immunotherapy.
5. BSACI: Allergic rhinitis patient information.
6. ARIA–EAACI 2024–2025 recommendations on intranasal treatments.