Adverse reactions to the injection of face and neck aesthetic filling materials: a systematic review.

Background: Adverse reactions, caused during the inflammation and healing process, or even later, can be induced by the injection of dermal filler and can present a variety of clinical and histological characteristics. In this study we aimed to review the adverse reactions associated with the injection of aesthetic filling materials in the face and neck.
Material and Methods: The review was reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist. Studies published that mentioned adverse reactions in patients with aesthetic filling materials in the face or neck were included. Risk of bias was assessed using the Joanna Briggs Institute appraisal tool. After a 2-step selection process, 74 studies were included: 51 case reports, 18 serial cases, and five cohorts.
Results: A total of 303 patients from 20 countries were assessed. Lesions were more prevalent in the lip (18%), nasolabial folds (13%), cheeks (13%), chin (10%), submental (8%), glabella (7%), and forehead (6%). Histopathological analysis revealed a foreign body granuloma in 87.1% of the patients, 3% inflammatory granuloma, 3% lipogranuloma, 2.3% xanthelasma-like reaction, 1% fibrotic reaction, 0.7% amorphous tissues, 0.7% xanthelasma, 0.3% sclerosing lipogranuloma, 0.3% siliconoma, and 0.3% foreign body granuloma with scleromyxedema. In addition, two patients displayed keratoacanthoma and two others displayed sarcoidosis after cutaneous filling. The most commonly used materials were silicone fillers (19.7%), hyaluronic acid (15.5%), and hydroxyethyl methacrylate/ethyl methacrylate suspended in hyaluronic acid acrylic hydrogel (5.6%). All patients were treated, and only 12 had prolonged complications.
Conclusions: There is evidence that adverse reaction can be caused by different fillers in specific sites on the face. Although foreign body granuloma was the most common, other adverse lesions were diagnosed, exacerbating systemic diseases. In this way, we reinforce the importance of previous systemic evaluations and histopathological analyses for the correct diagnosis of lesions.