Differentiating Bell's Palsy From Lyme-Related Facial Palsy.

BACKGROUND AND OBJECTIVES: To describe the etiology and clinical course of pediatric acute-onset unilateral peripheral facial palsy (FP), to define factors that distinguish Bell's palsy from Lyme-related FP (LRFP), and to determine if early corticosteroid use impacts facial strength recovery in Bell's palsy or LRFP. METHODS: Retrospective cohort study of children 1 to 18 years old who received clinical care within our pediatric clinical care network (Lyme-endemic region) between 2013 and 2018 for acute-onset unilateral peripheral FP. RESULTS: The study included 306 children; 82 (27%) had LRFP, 209 (68%) had Bell's palsy, and 15 (5%) had FP of different etiology. Most children with LRFP presented between June and November (93%), and compared with Bell's palsy, more often had a preceding systemic prodrome, including fever, malaise, headache, myalgias, and/or arthralgias (55% vs 6%, P < .001). Neuroimaging and lumbar puncture did not add diagnostic value in isolated FP. Of the 226 children with Bell's palsy or LRFP with documented follow-up, FP was resolved in all but 1. There was no association between ultimate parent/clinician assessment of recovery and early corticosteroid use. CONCLUSIONS: Bell's palsy and LRFP were common causes of pediatric FP in our Lyme endemic region. Systemic prodrome and calendar month may help distinguish LRFP from Bell's palsy at FP onset, guiding antibiotic use. Early corticosteroid use did not impact our measures of recovery, although subtle abnormalities may not have been appreciated, and time to recovery could not be assessed. Future prospective studies using standardized assessment tools at regular follow-up intervals are necessary.