Abstract
Although only recently introduced, chemically-modified hyaluronic acid dermal fillers have gained widespread acceptance as "redefining" dermal fillers in the fields of dermatology and cosmetic facial surgery. Although hyaluronic acid-based dermal fillers have a low overall incidence of long-term side effects, occasional adverse outcomes, ranging from chronic lymphoplasmacytic inflammatory reactions to classic foreign body-type granulomatous reactions have been documented. These long-term adverse events are reviewed.