Safety of sublingual immunotherapy started during the pollen season

Sublingual immunotherapy (SLIT) is safer than subcutaneous immunotherapy (SCIT) and this has lead to the reconsideration of the use of ultra-rush schedules for SLIT. The aim of this study was to assess the safety of ultra-rush SLIT in pollen-allergic children according to different timing of administration in relation to the pollen season.

In total, 34 children with pollen-induced rhinitis and 36 with pollen-induced asthma and rhinitis, were enrolled and assigned to three study groups: group 1 (n = 17 patients): conventional pre-seasonal-SLIT treatment; group 2 (n = 23 patients), seasonal SLIT ended before the pollen seasonal peak; group 3 (n = 30 patients), SLIT began after the pollen seasonal peak and ended after the pollen season. SLIT was performed using extracts from Stallergenes (Antony, France) and following an ultra-rush schedule, consisting in four doses at a 30-min intervals, and maintenance treatment by administering the top dose three times a week.

In all, 54 adverse events (AEs) were reported: 12 in nine patients in group 1 (9/17, 52.9%), 22 in 14 patients in group 2 (14/23, 60.9%), and 20 in 13 patients in group 3 (13/30, 43.3%). No statistically significant differences were found between the three groups. Local AEs (oral itching and burning) were short lasting and self-resolving. Systemic AEs were also mild, except for a case of asthma, which lasted 5 days, in a patient from group 1. There were no severe reactions, and none of the patients dropped out.

This study suggests that SLIT with pollen extracts may be safely started at the beginning and also during the pollen season, with a tolerability profile comparable to the conventional pre-seasonal SLIT.