Characteristics of pediatric recurrent acute mastoiditis: A case-control study.

BACKGROUND: Data on pediatric recurrent acute mastoiditis are lacking, despite its morbidity and clinical significance. Our aim was to describe the incidence, characteristics, and associated factors of recurrent mastoiditis in hospitalized children. METHODS: Using a case-control design, analyzing electronic data of hospitalized children with acute mastoiditis between June 2011 and December 2018, children with recurrent mastoiditis were compared to children with a single episode at the time of hospitalization. Recurrent episodes of mastoiditis were compared to the first episodes. Recurrent acute mastoiditis was defined as recurring mastoiditis ≥4-weeks after a completely resolved event. RESULTS: Of 347 children hospitalized with acute mastoiditis, 22 (6.3%) had recurrent mastoiditis; the median interval between episodes was 3 months (range: 1-36). The mean ± SD age was 2.3 ± 2.25 years. A comparison of first episodes in recurring cases to single episodes by univariate and multivariate analysis, showed no differences in the pre-admission management or in the isolated pathogens; however, a history of atopic dermatitis and percutaneous abscess drainage were more frequent in first episodes of recurring cases (27.3% vs. 1.2%, p < 0.001, and 27.3% vs. 10.0%, p = 0.026, respectively). The second episode of acute mastoiditis was characterized by a milder clinical course and shorter durations from symptoms to hospitalization, intravenous antibiotic therapy, and length of hospital stay. Linear regression showed that an increased interval from symptoms to hospitalization significantly increased length of hospital stay (regression coefficient of 0.215 [95% CI: 0.114-0.317], p < 0.001). CONCLUSIONS: Recurrent episodes of mastoiditis were clinically milder, with shorter length of hospital stay compared to first episodes, possibly because of early admission.