Sublingual immunotherapy (SLIT) was introduced in the treatment of respiratory allergy as an option to subcutaneous immunotherapy (SCIT), which is clinically effective but has the problem of adverse systemic reactions, quite rare but sometimes life-threatening. A large number of trials, globally evaluated in several meta-analyses, demonstrated that SLIT is an efficacious treatment for allergic rhinitis and allergic asthma and has a satisfactory safety profile, severe reactions being extremely rare, though an increased risk is apparent in subjects undergoing SLIT because of previous systemic reactions to SCIT.
The suitability of SLIT is ensured by a good compliance, higher than reported for SCIT, the injections being a major factor for noncompliance with the latter, and by its cost-effectiveness performances. In fact, a number of studies showed that SLIT may be very beneficial to the healthcare system, especially after its stopping, when there is no more the cost of the treatment but its efficacy on symptoms persists.
