*Statistical Analysis*

The sample size was calculated from a pilot study [12], in which ESS improved by 2.85 ± 1.75 following the use of propranolol gel. We anticipated a similar improvement in the current study. We assumed an improvement in ESS of 0.5 in the placebo group. Power analysis calculation ( α of 0.05 and 1-β of 0.8) required 9 patients in each arm. Assuming that two participants would drop out of the study per group, 11 participants were planned to be recruited in each group (for a total of 22 participants in the study).

Data were analyzed using SPSS, version 25. Armonk (NY, USA) (SPSS Inc., Chicago, IL, USA). Demographic factors and clinical outcomes were summarized with percentage breakdown. For comparing outcomes between the treatment groups, an independent samples *t*-test was used, with a normal distribution assumed. Otherwise, Mann–Whitney or Wilcoxon rank-sum tests were used. Changes in ESS and clinical parameters between two visits were analyzed using a paired *t*-test. To analyze the improvement in nasal rhinology scoring between the two groups (improved/not improved), the McNemar test was used. Normality assessment was performed using a Shapiro–Wilk test. Normal distribution was assumed when *p* > 0.05.
