A Randomized, Double‐Blind Study Comparing Corticosteroid Irrigations and Nasal Sprays for Polyp Size Reduction in <scp>CRSwNP</scp>

ABSTRACT Objective To compare the efficacy of corticosteroid irrigation (CSI) and intranasal corticosteroid spray (INCS) in reducing polyp size, improving nasal symptoms, and assessing HPA‐axis suppression in non‐surgical patients with chronic rhinosinusitis with nasal polyps (CRSwNP). Methods Twenty‐four patients from the Allergy and Rhinology Clinic, Songklanagarind Hospital, were randomized into: CSI + placebo spray ( n = 13): Budesonide irrigation (0.5 mg/day) + saline spray. Placebo irrigation + INCS ( n = 11): Saline irrigation + budesonide spray (512 mcg/day). Nasal symptoms were assessed using VAS‐TNSS and SNOT‐22. Polyp grading was evaluated via video nasal endoscopy using mLKS and Lildholdt's scale. Serum cortisol levels were measured at baseline, 4–12 weeks. Results After 12 weeks, the CSI + placebo spray group showed a significant reduction in mLKS scores (8.54 ± 1.94 vs. 4.82 ± 1.94; p &lt; 0.001), with greater improvement than the placebo irrigation + INCS group (Δ4 (3, 4) vs. Δ1 (0, 2); p = 0.003). VAS‐TNSS and SNOT‐22 scores showed no significant differences. Serum cortisol levels remained normal. Conclusion Corticosteroid irrigation is more effective than nasal sprays in improving mLKS scores in non‐surgical CRSwNP patients after 12 weeks, with no evidence of HPA‐axis suppression. Level of Evidence 2.