Adverse Events and Complications of Hyaluronic Acid Lip Augmentation: A Critical Review and Evidence-Based Management Algorithm for Dental Practitioners

Objectives: To critically synthesize the current evidence on adverse events (AEs) and complications of hyaluronic acid (HA) lip augmentation and to propose a structured, evidence-informed management algorithm applicable to dental practice. Methods: A critical narrative review with systematic search elements, reported in accordance with SANRA. PubMed/MEDLINE, Scopus, Web of Science, Embase, SciELO and LILACS were searched from 2000 to October 2025, with emphasis on 2020–2025, using keywords combining hyaluronic acid, lip augmentation, complications, vascular occlusion, hyaluronidase and delayed inflammatory reactions. Human studies, systematic reviews, meta-analyses, randomized trials, cohorts, case series, anatomical/ultrasound investigations and consensus documents were eligible; a narrative synthesis was organized by onset and mechanism, and the algorithm was developed by triangulating consensus documents and recent systematic reviews. Results: AE rates are high but predominantly mild and transient. In a meta-analysis of 1,496 patients, tenderness occurred in 88.8%, swelling in 74.3% and bruising in 39.5%; the pooled prevalence of treatment-related AEs after lower-face HA was 63.0% (95% CI 35–84%), and serious AEs were approximately 1.1%. Vascular occlusion is rare (~0.015%, roughly 1:6,600) but potentially devastating; granulomatous foreign-body reactions occur in 0.02–0.4% of cases. Early intervention within 4–6 hours improves prognosis, with early-stage ischemia reversible in up to 80% of patients. Conclusions: Most AEs of lip augmentation are predictable and largely preventable through product selection, superficial plane technique, patient selection and asepsis. A time-and-severity-based management algorithm, with mandatory vascular screening, high-dose pulsed hyaluronidase and a graded ladder for late inflammatory nodules, is proposed to standardize care in the dental setting.