Immunotherapy -- also known as desensitisation or allergen-specific immunotherapy (AIT) -- is the only treatment that addresses the cause of hay fever rather than merely suppressing the symptoms. In 70--80% of patients it leads to a significant reduction in symptoms.
In brief: with immunotherapy the immune system is gradually exposed to the allergen (via injections or tablets) over 3--5 years. It learns to tolerate the allergen instead of reacting strongly to it. Result: fewer symptoms and less medication.
How does immunotherapy work?
With immunotherapy the immune system is gradually exposed to increasing amounts of the allergen that causes the hay fever (for example birch pollen or grass pollen extract). Through this repeated exposure, the immune system learns to tolerate the allergen instead of reacting strongly to it.
Two forms: injections or tablets
SCIT -- injections
Build-up phase (~3 months): weekly injections with a gradually increasing dose, at the allergist's office.
Maintenance phase: monthly injections for 3--5 years.
Note: you must wait 30 minutes at the hospital after each injection for observation.
SLIT -- tablets or drops
Daily: tablet or drops placed under the tongue, where they dissolve.
First dose: at the hospital; then at home.
Duration: 3--5 years daily, year-round.
Available: Grazax (grass pollen), Itulazax (birch pollen).
What are the results?
Significantly fewer symptoms
The majority experience substantial improvement with less or no medication. Many patients notice a difference as early as the first season.
Completely symptom-free
Some become completely symptom-free after treatment, without any medication. The second and third years often bring further improvement.
No improvement
A small percentage unfortunately experience no improvement. Immunotherapy does not work for everyone.
In people with a cross-allergy to birch pollen, immunotherapy can also reduce reactions to foods.
Side effects
With injections (SCIT)
Common: swelling, redness or itching at the injection site (harmless).
Rare: breathlessness, drop in blood pressure. This is why you wait 30 minutes after injection.
With tablets (SLIT)
Common: itching in the mouth, itchy ears, sneezing, throat irritation, mouth swelling. Diminishes after the first few weeks.
Rare: serious allergic reaction (very rare with SLIT).
Who is immunotherapy suitable for?
Suitable if: antihistamines and nasal spray are not helping enough, hay fever has caused severe symptoms for at least two seasons, and a specific pollen allergy has been confirmed with an allergy test.
Not suitable for: severe or unstable asthma, conditions that suppress the immune system, use of certain heart medication (beta-blockers), or children younger than 5 years.
How do you get started?
The route to immunotherapy goes through your GP. They will refer you to an allergist at the hospital for diagnostics (blood test and/or skin prick test). If immunotherapy is indicated, treatment usually starts outside the pollen season -- for grass pollen this means in autumn or winter.
Reimbursement
Immunotherapy is covered by basic health insurance in the Netherlands. The costs fall under the annual deductible (eigen risico). The allergist and your health insurer can inform you about the specific conditions.