Background Over the last few decades, the level of pollen from birch and homologous trees has increased in parts of Europe. Sensitization to birch pollen allergens (principally Bet v 1) has been associated with food cross‐reactivity called pollen‐food‐allergy syndrome (PFAS). Objective To evaluate changes in allergic diseases due to IgE sensitization over 25 years in asthmatic children. Methods This was a cross‐sectional retrospective study conducted in Paris. We analyzed two cohorts of asthmatic children with similar characteristics explored between 1993‐1999 (old cohort=OC) and 2012‐2018 (recent cohort=RC). Results 121 children were in the OC and 120 in the RC. An increase in sensitization to tree pollens was found especially for birch pollen which was 11.6% in the OC and 31% in the RC (p=0.0002). Allergic rhinitis prevalence was significantly higher in the RC than in the OC (96% vs 52%, respectively, p<0.0001). IgE‐mediated food allergy increased from 6% to 16% in the OC and RC, respectively, (p = 0.01) mainly due to PFAS. In the RC, a higher mean Bet v 1‐specific IgE level was observed in children with PFAS compared to children without (105.7 KU/L± 17.8 and 48.9 kU/L ± 15.7, respectively, p<0.05). Conclusion Allergic rhinitis and food allergy with tree‐pollen sensitization has increased in Paris over 25 years mainly due to PFAS. Environmental factors could be responsible for these modifications as described in literature.