Recurrent respiratory infections (RRI) are an intriguing challenge for both otolaryngologists and paediatricians. Therefore, to prevent RRI is an ambitious target in clinical practice. In this regard, modulation of the immune system may have a critical role. Sinerga, a dietary supplement (containing: palmitoylethanolamide (PEA), Kluyveromyces marxianus B0399, bovine colostrum, and phenylalanine), was supplemented in 20 allergic children with RRI (20/30 days per 3 months) and treated with standard therapy (antihistamine plus intranasal corticosteroid). Other 20 allergic children with RRI were treated only with standard therapy. Sinerga significantly reduced the number of RI and the size of both inferior and middle turbinate consistently with the postulated mechanisms of action. In conclusion, the current study demonstrated that Sinerga supplementation in allergic children with RRI may significantly prevent RI and reduce events depending on allergic inflammation.