The German Weather Service (DWD) forecasts an average winter for the coming months. This is good news for people with pollen allergies, because if the winter is cold, pollen counts will not be high in December with any luck.
All the same, people with pollen allergies should not wait to undergo allergen-specific immunotherapy (SIT, AIT) – previously also referred to as hyposensitisation. Even now is not too late to start.
What can be achieved with specific immunotherapy?
The idea behind SIT is to allow the body to get used to the pollen gradually. The therapy teaches the immune system not to overreact to pollen, which is actually harmless. The allergy can then be kept under control.
SIT has an impact on any existing symptoms of hay fever in the eyes and nose, which not only significantly affect quality of life, but also day-to-day functioning.
But it is also important for a second reason: SIT helps prevent allergic asthma, the most serious consequence of hay fever. When asthma occurs, the respiratory tract is permanently inflamed and causes not only coughing, but also wheezing and shortness of breath. In fact, around 30 per cent of all people with allergic diseases of the upper respiratory tract develop asthma sooner or later. SIT prevents this “allergic march”, or progression from the upper respiratory tract to the lungs.
How does SIT work?
Step 1 – Identify allergy triggers.
First, the allergens triggering the symptoms are identified. After a detailed interview, the doctor usually performs a skin test (prick test) and/or takes a blood sample. The blood is tested to determine the level of antibodies it contains against certain allergens. For example, the level of immunoglobulin E (IgE) antibodies against birch pollen is measured.
This first step is important for the success of the treatment, so you should go directly to the allergy specialist for the examination. Allergy experts know, for example, that in many cases, people with allergies to birch and hazel also react to oak and chestnut. This is why these allergy triggers are investigated at the same time.
The diagnosis of allergens has become more and more accurate in recent years. This is above all thanks to molecular allergy diagnostics, which enable the detection of antibodies not only against allergens such as birch pollen, but also against individual birch pollen components. This also makes the treatment more precise. Knowing exactly which protein the body reacts to allows the treatment to prepare the body against it precisely.
Step 2 – Administer a small trial dose.
If the exact allergy trigger is known, a small dose can be administered. At first a minuscule amount is given, then the dose is gradually increased. This allows the immune system to get used to it gradually. The allergy triggers are either injected into the upper arm under the skin (subcutaneous specific immunotherapy, or SCIT), or taken as a tablet or drop under the tongue (sublingual specific immunotherapy, or SLIT).
The market for allergen preparations manufactured especially for SIT has grown a lot in recent years. But now they are also subject to stricter controls: By 2025 at the latest, the main artificially produced allergens must be approved by health authorities before they can be prescribed by doctors and reimbursed by health insurance providers.
Step 3 – Maintain dosage for three years.
Once the so-called maintenance dose has been reached, the allergen must continue to be administered for a longer period – usually three years. After that, the allergic reactions are usually noticeably and permanently reduced.
Whether to use drops or injections for treatment should be discuss beforehand with the doctor. Each method has its advantages and disadvantages.
The best treatment option
“We discuss treatment options with the patient and decide which one is the best for each individual. Many of my patients opt for a regular injection at the clinic because they don’t want to have to remember to the drops every day”, says Professor Dr Torsten Zuberbier, ECARF expert and director of the Allergy Centre at Charité in Berlin.
There are generally four SIT options:
- SCIT for one year: The allergen is first injected every week (10-12 weeks) until the maintenance dose is reached. The maintenance dose is then injected every month. Each injection requires a doctor’s visit.
This is the traditional method used by people who receive individual allergens. These are allergen cocktails specially prepared for the allergy of a specific individual. Those who react to common allergens for which standard, mass-produced cocktails are available can use the following schedules.
- Pre-seasonal SCIT: In this “short-term therapy”, the allergen dose is increased rapidly in the initial phase. In this way, the maintenance dose can be achieved earlier. The maintenance dose injection is also administered monthly in the doctor’s office. Therapy is put on hold during the pollen season. This means fewer injections and fewer doctor’s visits overall.
- SLIT for one year: The patient self-administers the allergen every day. A doctor’s visit is only necessary at the beginning and on monitoring dates. The disadvantage is that the patient has to remember to take the tablet or the drops every day.
- Pre-/co-seasonal SLIT: For this schedule, the patient self-administers the allergen four months before and during the pollen season. A doctor’s visit is also necessary in this case at the beginning of the treatment and on monitoring dates. But there are fewer doctor’s visits overall. The disadvantage in this case is also having to remember to take the tablet or the drops.
Specific immunotherapy and COVID-19
Should allergy-specific immune therapy still be followed during the coronavirus pandemic? DGAKI (German Society of Allergology and Clinical Immunology) recommends it if possible, as long as the patient is healthy and has no symptoms of COVID-19. “If you have signs of infection, such as fever, dry cough or overall discomfort, SIT should be discontinued and started again at a later time (when symptoms have subsided)”, according to the specialis society. Patients who must interrupt SCIT or SLIT should see their doctor for a check-up before starting treatment again.