What is Sublingual Immunotherapy?

Sublingual immunotherapy (SLIT) is an allergy treatment involving introduction of trace amounts of allergens under the tongue to a patient to decrease sensitivity over time. It is an alternative to injections, also known as allergy shots. It is important for the treatment to be supervised by a doctor, as there are potential risks and complications if patients attempt sublingual immunotherapy on their own, including the risk of anaphylaxis and death if too much of an allergen is given.

In this treatment, patients take tablets or drops containing a solution of an allergen several days a week or every day, depending on the dosing schedule. The allergen is absorbed through the less reactive mucus membranes of the mouth, allowing the immune system to become familiar with it and to learn to react with less extreme measures when the patient is exposed to the allergen. Over time, patients on sublingual immunotherapy can eventually reach a point where they can safely be around or consume an allergen.

Dosing is variable, as patients all react slightly differently. Patients experiencing problems like gastrointestinal distress, skin irritation, and tenderness around the mouth are taking too much and their dosage needs to be backed down to a safe level, with breaks at each reduction in dosage to allow the body to recover and see if the new dosage will work. In very rare cases, sublingual immunotherapy can cause a patient to experience anaphylaxis, where the airways close and the patient can no longer breathe.

Slow exposures over time will gradually blunt immune responses to allergens. The level of success achieved can depend on the allergen and the patient. Some patients have less severe allergies, so they can safely be in environments where the allergen is present. Other patients may be able to closely interact with known allergens without experiencing ill effects. Usually, exposures to the allergen in the real world are medically supervised at first to make sure the patient is safe.

This treatment option is not available everywhere. In some regions, only allergy shots, and no sublingual immunotherapy, are available for management of allergies. Patients interested in this treatment can talk with their physicians to see if it is available and suitable for the treatment of their conditions. Patients should plan on spending weeks or months in treatment, as the process is very gradual, and they need to be able to stick with the regimen through to the end.