Predictors of ENT Referral and Microlaryngobronchoscopy Findings in Children With Recurrent Croup: A 10‐Year Cohort Study

OBJECTIVE: To determine predictors of ENT referral and microlaryngobronchoscopy (MLB) findings in children with recurrent croup. DESIGN: Retrospective cohort study. SETTING: Large district general NHS trust (2013-2023). PARTICIPANTS: Children < 18 years with ≥ 2 croup episodes in 12 months or a clinician diagnosis of recurrent croup. MAIN OUTCOME MEASURES: ENT referral, MLB performance and abnormal MLB findings. RESULTS: 128 children met recurrent croup criteria (median age 13.5 months, median 5 episodes). Sixty-two (48%) were referred to ENT, of which 34 (55%) underwent MLB. Thirteen (38%) MLBs were normal. Abnormalities included subglottic stenosis (n = 5), dynamic airway collapse (n = 4), vocal-cord pathology (n = 3), non-specific inflammatory/irritative change (n = 3) and subglottic lesions (n = 5), with the latter requiring surgical excision. Referred children were younger (median 12 vs. 17 months, p = 0.038) and had more episodes (median 5.5 vs. 4.0, p = 0.013). ENT referral correlated with ENT-related conditions (26%, p < 0.001), gastro-oesophageal reflux (24%, p = 0.021) and recurrent viral infections (47%, p = 0.022). MLB was more common with ENT-related conditions (38%, p < 0.001) and reflux (32%, p = 0.003). After adjustment, only episode count predicted ENT referral (aOR 1.09 per episode, 95% CI: 1.01-1.19), no factor predicted MLB or abnormal findings. CONCLUSIONS: ENT review is warranted for recurrent croup, whereas MLB should be reserved for children with red-flag features suggesting significant airway pathology. Although most scoped children had normal or conservatively managed findings, a meaningful minority had clinically important abnormalities, including subglottic lesions requiring surgical intervention. Conventional risk factors offer little predictive value, supporting prospective multi-centre studies to refine risk-stratification.