What is sublingual immunotherapy?
Sublingual allergen immunotherapy, commonly referred to as SLIT, is a long-term treatment designed to reduce allergic symptoms by gradually retraining the immune system. Instead of injections, SLIT involves placing allergen extracts under the tongue on a regular basis, usually daily.
SLIT is most commonly used to treat environmental allergies such as dust mite and grass pollen allergy. In Australia, it is prescribed and supervised by clinicians with training in allergy management and is increasingly chosen by patients seeking a needle-free, home-based alternative to injectable immunotherapy.
Like all immunotherapy, SLIT requires commitment over several years. For appropriately selected patients, it may lead to sustained improvement in symptoms and quality of life.
How SLIT works: the immune science explained
SLIT works by delivering small, controlled amounts of allergen to immune cells located in the lining of the mouth. These immune cells play a key role in teaching the immune system how to tolerate substances that would otherwise trigger allergy symptoms. With regular exposure over time, SLIT promotes:
- Reduced sensitivity of allergy-driving immune pathways
- Increased production of protective antibodies
- Greater immune tolerance to everyday allergen exposure
These changes occur gradually. Most patients begin to notice improvement after several months, with benefits continuing to build over the first one to two years of treatment.
The SLIT treatment journey
1.Initial assessment and first dose
SLIT begins with a comprehensive allergy assessment. The first dose is often administered under medical supervision to assess tolerance and provide education on correct use.
2.Home-based daily treatment
After the initial dose, treatment is usually continued at home. Drops or tablets are placed under the tongue and held for a short period before swallowing, according to specific instructions. Consistency is essential. Missing doses may reduce effectiveness.
3.Long-term maintenance
SLIT is typically continued daily for at least three years. Regular follow-up appointments allow your clinician to monitor progress, manage side effects, and adjust treatment if required.
4.Completion and ongoing management
After completing the planned course, treatment is stopped. Many patients experience lasting benefit, although some may continue to require medications or other management strategies.
