Intralesional injection treatment of hypertrophic scars and keloids: a systematic review regarding outcomes

Background: The aim of this review was to explore the existing body of literature focusing on the intralesional treatments of keloids and hypertrophic scars. Methods: A comprehensive systematic review of related articles was conducted across multiple databases. Article selection was limited to those published in the English language between 1950 and 2014. Search terms for the on-line research were "scar(s)," "keloid(s)," "hypertrophic," "injection," "intralesional," and "treatment". Results: The initial search returned 2548 published articles. After full text review, the final search yielded 11 articles that met inclusion criteria. A total of 14 patient samples in 11 articles were collected. The most frequent intralesional injection treatment studied was triamcinolone (n = 5), followed by bleomycin (n = 3), 5-fluorouracil (n = 2), verapamil (n = 2), cryosurgery, and collagenase. The scar height reduction for all but one study was demonstrated, with acceptable complication and recurrence rate. Only three articles reported a follow-up period longer than 18 months, and only two studies used standardized outcome criteria with a quantitative scale. Conclusions: Although many treatment options have already been described in the literature, there is no universally accepted treatment resulting in permanent hypertrophic or keloid scar ablation. The lack of adequately long-term powered randomized controlled trials does not permit to establish definitive conclusions with implications for routine clinical practice.