A 19-year follow-up study was carried out to explore the long-term effect of intralymphatic immunotherapy (ILIT) on the quality of life and efficacy of the treatment in allergic rhinitis patients.

Patients who underwent ILIT and subcutaneous immunotherapy (SCIT) treatment, as well as another group of patients who finished SCIT, were enlisted. A conventional Rhinoconjunctivitis Quality of Life Questionnaire and an internal survey tailored specifically for the trial were given to each participant. Off-season and on-season data were collected. Descriptive statistics were used.

The findings of the study indicated the long-term effectiveness of ILIT for treating rhinoconjunctivitis due to sensitization to grass pollen allergens. Notably, 25 (43%) and 29 (54%) of the original 58 and 54 patients who got ILIT or SCIT, respectively, returned the questionnaires for examination. As found, 15 (60%) and 20 (69%) of the ILIT and SCIT patients, respectively, expressed satisfaction with the allergy immunotherapy they got.

Four (16%) and three (11%) of these patients attained complete protection against grass pollen-mediated rhinitis. Any persisting effects were described as modest in both groups. Comparable amounts of medication were taken by the SCIT and ILIT groups. Additionally, 23 (79%) in the SCIT group and 19 (76%) patients in the ILIT group said they were pleased with their allergy immunotherapy.

Nineteen years after treatment, allergic rhinitis patients treated with grass pollen ILIT exhibited considerable improvement in their quality of life, and this impact was comparable to that of SCIT.