Efficacy of sublingual immunotherapies (SLIT) is mostly demonstrated during or immediately after the therapy, but little is reported about long-term efficacy.

121 phone interviews were performed to analyze the state of patients after SLIT. All patients were children who were treated in two centers in Germany. Questionnaires were developed and standardized with respect to statistical and social rules. 19 questions were designed to elucidate the subjective estimation of allergic symptoms (conjunctivitis, rhinitis, asthma, atopic dermatitis), duration of therapy (> 2 years), duration of preexisting allergy, type of allergen, symptomatical medication, age, gender and others before starting SLIT, immediately after SLIT and 1 to 6 years after having finished the therapy. All interviews were conducted with the patients’ mothers. Due to ethical considerations, for this period of up to 9 years after initiation of treatment, formation of a placebo control group was impossible.

In summary, the general state of health improved significantly in 93% of all patients during therapy. This was similar for all single symptoms. During the period after therapy, 84% of patients did not feel any worsening of their state and 15% reported a very slight return of symptoms. At the same time, no patient felt worse than before initiating SLIT, and 8% felt similar to the state before. Results were equal 1, 3 and 5 years after termination of SLIT.

In comparison to the expectable allergic march, which implicates a high risk of intensifying symptoms in untreated patients, SLIT treated patients improved and demonstrated a long-lasting clinical effect (5 years) of the therapy. Rates of improvements are higher than spontaneous remissions (age dependently, 5 – 25%) as reported in previous studies.