Post-marketing survey on the safety of sublingual immunotherapy in children below the age of 5 years

Background The age below 5 years is considered a prudential limit for immunotherapy in view of the possible severity of side-effects. Sublingual immunotherapy (SLIT) seems to be safe, but no study in very young children is available. We performed a safety post-marketing surveillance study in children below 5 years. Methods Children aged 3-5 years with respiratory allergy receiving SLIT were followed-up for at least 2 years. A diary card for side-effects was filled by parents at each dose given. Local and systemic side-effects were graded as: mild (no intervention, no dose adjustment), moderate (medical treatment and/or dose reduction), severe (life-threatening/hospitalization/emergency care). The comparative safety of different allergens and regimens was also assessed. Results One hundred and twenty-six children (mean age 4.2 years, 67 male) were included. Seventy-six (60%) had rhinitis with asthma, 34 (27%) rhinitis only and 16 (13%) only asthma. Immunotherapy was prescribed for mites (62%), grasses (22.2%), Parietaria (11.9%), Alternaria (2.4%) and olive (1.5%). Eighteen children underwent an accelerated build-up. The total number of doses was about 39 000. Nine side-effects were reported in seven children (5.6% patients and 0.2/1000 doses). Two episodes of oral itching and one of abdominal pain were mild. Six gastrointestinal side-effects were controlled by reducing the dose. All side-effects occurred during up-dosing phase. No difference in terms of safety among the allergens used was observed. Conclusion SLIT is safe also in children under the age of 5 years.