Adult-onset Still Disease Flare 5 Days Following Poly-l-lactic Acid Injection: A Cautionary Tale for Aesthetic Practice.

Adult-onset Still disease (AOSD) is a rare systemic autoinflammatory disorder characterized by quotidian fevers, evanescent rash, and polyarthritis. Minimally invasive aesthetic procedures are increasingly common, yet their immunological safety in patients with underlying autoimmune disease remains poorly characterized. We report a 57-year-old woman with AOSD, previously stable on annual rituximab (1 g), who developed a severe systemic flare temporally associated with a poly-l-lactic acid facial injection, with symptom onset 5 days after the procedure. She presented with high-grade pyrexia (40°C), extreme leukocytosis (white blood cell, 26 × 109/L), C-reactive protein (230 mg/L), and acute arthritis of the hand joints, requiring inpatient intravenous corticosteroids and intravenous rituximab. This case raises the possibility that collagen-stimulating biomaterials may act as an immunological trigger for systemic autoinflammatory relapse in predisposed patients; however, causality cannot be inferred from a single observation, and the relationship described here is strictly temporal. As a conceptual, hypothesis-generating proposal, a structured preprocedural risk assessment and multidisciplinary perioperative protocol are suggested for consideration before elective aesthetic procedures in AOSD patients, pending validation in larger series.