Sublingual Immunotherapy: “Allergy Vaccination” Without Needles

Spring and summer time: for most people a reason to rejoice, for pollen allergy sufferers this time is associated with a runny nose, itchy eyes and breathing difficulties. Specific immunotherapy can effectively combat the causes of hay fever – now even with drops instead of injections. This is called sublingual immunotherapy (SLIT). You can find out how the “allergy vaccination” works and what needs to be taken into account here.

Pollen makes life difficult for allergy sufferers

Hay fever sufferers have a hard time in the warm months: when others open their windows and ride their bicycles into the countryside, they have to postpone airing until nighttime, wash their hair before going to bed, and – if they have ventured outside – leave their clothes outside the bedroom door. Many allergy sufferers move their annual vacation to the high mountains to escape the pollen count. Although the symptoms can be alleviated with various remedies, those affected are always at risk of developing known or new symptoms, including allergic shock. Often the allergy worsens over the years or the symptoms shift from one organ to another. For example, allergy to grass or tree pollen may begin as swelling of the nasal mucosa and later develop into asthma of the lungs.

Allergy – hypersensitivity of the immune system.

The organism of an allergy sufferer reacts intensively to foreign but harmless substances – called allergens – judges them as dangerous and tries to fight them. In particular, the immune system forms immunoglobulin E antibodies, which can also be detected in the blood. These cause the typical symptoms of an allergy such as:

  • Mucosal swelling
  • Sneezing
  • Eye itching
  • Breathing difficulties

Cure through hyposensitization

Currently, the only way to get to the root of the evil is specific immunotherapy (SIT), also known as hyposensitization or “allergy vaccination”. With this, one starts at the principle of origin of the allergy. In hyposensitization, the body is regularly given the substance to which it is allergic, initially in very small doses and then in increasing doses. This causes it to become accustomed to it instead of fighting it aggressively.

Hyposensitization: injections versus swallowing.

For many years, specific immunotherapy has been successfully performed using subcutaneous immunotherapy (SCIT)-that is, treatment by injection. Over three years, the patient receives an injection with increasing doses under the skin (subcutaneously) on the upper arm, initially weekly and later monthly. Afterwards, he or she must remain in the practice for at least 30 minutes, as allergic reactions requiring treatment may occur. All in all, SCIT is therefore a very time-consuming procedure that requires discipline and stamina on the part of the affected person. Another option may be “allergy vaccination” by drops or tablets.

SLIT: Sublingual immunotherapy as an alternative.

As an alternative, sublingual immunotherapy (SLIT) has now been known for several years. Here, the allergy sufferer dribbles a certain number of drops daily under his tongue (sublingual) or takes tablets. The preparation must then be kept under the tongue for a few minutes and then swallowed. Again, the treatment is carried out over a period of three years and the dose is increased according to a set schedule. The patient must see the doctor regularly. In the case of sublingual immunotherapy, it should be noted that the drops or tablets should not be taken immediately after brushing the teeth. This is because this irritates certain areas of the oral mucosa and side effects such as itching may occur there.

For which allergies does hyposensitization help?

Hyposensitization is used primarily to treat allergies to pollen and – particularly successfully – allergies to bee and wasp venom. For the latter, the success rate is 90 percent; for pollen allergy, it is 60 to 70 percent, and for allergy to dust mites, 50 percent. The method is less recommended for allergies to spores of molds or animal hair, for neurodermatitis, or for a food allergy.Hyposensitization is less appropriate for people with severe asthma and patients taking beta blockers for cardiovascular disease.

When should hyposensitization be done?

In both forms of hyposensitization, the physician uses various tests to determine which allergens the affected person reacts to before starting therapy. Treatment should be started during the pollen-free season in the fall and, if possible, before allergies to multiple substances, more severe forms, or allergic asthma have developed. Therapy is already possible in childhood.

Advantages of sublingual immunotherapy

The advantages of sublingual immunotherapy are initially obvious:

  • The treatment is painless.
  • Sufferers do not need to constantly visit a doctor’s office, but can take the drops or tablets independently in any place.
  • The time required is less and fewer appointments with the doctor are necessary.
  • There is less risk of allergic shock and other side effects.

Disadvantages of sublingual immunotherapy

On the other hand, there are also some disadvantages:

  • Sublingual immunotherapy has a lower chance of success than subcutaneous immunotherapy.
  • Sublingual immunotherapy in tablet form has so far been approved only for certain allergens.
  • There are in contrast to subcutaneous immunotherapy for all allergens clinical (long-term) experience and not available.
  • There have been few studies of this treatment (especially in childhood and in direct comparison with SCIT) and the results are partly contradictory.
  • It must be taken daily.

How does sublingual immunotherapy work?

Ultimately, in the case of sublingual immunotherapy, the exact principle of action is not known. Scientists assume that it is not a “swallow vaccination,” meaning that the drops work even if they do not enter the gastrointestinal tract. Presumably, they cause the cells of the oral mucosa to produce certain substances that inhibit the production of the immune cells that cause allergies. Therefore, sublingual immunotherapy has not yet been recognized as having the same status as the subcutaneous form.