Refractory Keloids and Hypertrophic Scars: Immune Dysregulation and Neuroimmune Mechanisms Underlying Treatment Failure

Keloids and hypertrophic scars are fibroproliferative disorders of wound healing characterized by excessive extracellular matrix deposition, constant inflammation, and high recurrence rates despite appropriate management. Conventional therapies, including surgical excision, corticosteroid injections, laser therapy, and radiation, can provide temporary relief. However, treatment failure remains common, specifically in refractory keloids. Recent findings suggest these outcomes cannot be fully explained by technical or mechanical factors alone, and pathological scarring may reflect underlying immune and neuroimmune dysfunction. Current evidence shows prolonged activation of pro-inflammatory and pro-fibrotic cytokine pathways like IL-6, TNF-α, TGF-β, and IL-17 drives sustain fibroblast activation and disrupts normal wound healing and remodeling. Additionally, the skin functions as an integrated neuro-endocrine-immune organ, allowing bidirectional communication between cutaneous nerves, immune cells, and stromal tissue. Neurogenic inflammation is mediated by neuropeptides, mast cell activation, and stress-induced hypothalamic-pituitary-adrenal axis dysregulation, which further amplifies inflammation within scar tissue. Psychiatric comorbidities like depression, anxiety, and chronic psychological stress serve as a positive feedback mechanism and are increasingly recognized as biologically active contributors to immune dysregulation. This review highlights critical gaps in current management strategies and emphasizes the need for biologically informed, multidisciplinary approaches to improve long-term outcomes for keloid and hypertrophic scar management.