Distinct Recurrence Patterns and Risk Factors Following Nonoperative Management of Acute Appendicitis versus Appendiceal Abscess in Children: Implications for Risk Stratification

Objective To compare recurrence patterns and identify risk factors after nonoperative management of acute appendicitis (AA) and periappendiceal abscess (PAA) in children. Methods In this retrospective cohort study, children (< 18 years) with AA or PAA (defined by imaging) and treated nonoperatively (Jan 2020–Jul 2024) were included. The primary outcome was clinical recurrence. Risk factors were identified using multivariable logistic regression and Kaplan–Meier analysis. Results Among 409 patients (median follow-up 38.8 months), recurrence was higher in the PAA group than in the AA group (26.5% vs. 14.9%), with earlier recurrence (HR 2.09, 95% CI 1.34–3.26; p < 0.001). In the PAA group, the presence of an appendicolith (adjusted odds ratio [aOR] 2.98, 95% CI 1.19–7.84) and a higher abscess-to-weight ratio at admission (aOR 1.12 per unit, 95% CI 1.01–1.26) were independent risk factors for recurrence, whereas a longer length of hospital stay was protective (aOR 0.89 per day, 95% CI 0.80–0.97). In the AA group, a negative pretreatment ultrasound finding was protective (OR 0.21, 95% CI 0.04–0.97). Surgical pathology of recurrent cases showed a predominance of gangrenous appendicitis in the PAA group versus suppurative appendicitis in the AA group (p = 0.032). Conclusion Following nonoperative management, PAA is associated with a high risk of early recurrence, driven by appendicolith and greater infectious burden, which justifies enhanced early surveillance and consideration of interval appendectomy. Recurrence risk in AA is lower and more protracted, particularly when ultrasound is negative. These findings support a risk-stratified approach to management.