Morning Versus Evening Dosing of Sublingual Immunotherapy in Allergic Asthma: A Prospective Study.

Background: Sublingual immunotherapy (SLIT) has been proved to be an effective and safe treatment for allergic asthma (AS) in children. Nonetheless, several issues regarding SLIT remain to be resolved, including the information about optimal administration timing. Methods: A total of 163 AS children aged 4-13 years were enrolled and randomized into the morning dosing (MD) group and the evening dosing (ED) group. Participants received SLIT with Dermatophagoides farinae drops between 7:00 a. m. and 9:00 a.m. (for the MD group) or between 8:00 p. m. and 10:00 p.m. (for the ED group). The total asthma symptom score (TASS), total asthma medicine score (TAMS), Asthma Control Questionnaire (ACQ), forced expiratory volume in one second (FEV1), FEV1/forced volume vital capacity (FVC), fractional exhaled nitric oxide (FeNO) and adverse events (AEs) were assessed at baseline, 0.5 and 1 year during the 1-year SLIT. Results: After 1 year, 62 patients in the MD group and 63 patients in the ED group completed the entire study. The clinical efficacy, pulmonary function and FeNO in both groups improved significantly at 0.5 and 1 year (p < 0.001). Compared to the MD group, the ED group showed significant lower ACQ score at 0.5 year (p < 0.001) and lower FeNO at 1 year (p < 0.05). No significant difference between two groups was observed in AE rate (p > 0.05). All AEs occurred in the first month, with no systemic AEs reported. Conclusion: 1-year house dust mite (HDM) SLIT is effective and well-tolerated in AS children regardless of administration time. SLIT dosing in the evening might enhance the asthma control level and reduce FeNO level compared with SLIT dosing in the morning.