Keloids: The paradigm of skin fibrosis — Pathomechanisms and treatment

Keloids, fibroproliferative dermal tumors with effusive accumulation of extracellular matrix (ECM) components, particularly collagen, result from excessive expression of growth factors and cytokines. The etiology of keloids is unknown but they occur after dermal injury in genetically susceptible individuals, and they cause both physical and psychological distress for the affected individuals. Several treatment methods for keloids exist, including the combination therapy of surgical excision followed by intralesional steroid therapy, however, they have high recurrence rate regardless of the current treatment method. Improved understanding of the pathomechanisms leading to keloid formation will hopefully identify pathways that serve as specific targets to improve therapy for this devastating, currently intractable, disorder. •Keloids are dermal tumors characterized by excessive accumulation of collagen.•The key cell responsible for matrix production is activated myofibroblast.•A number of growth factors, particularly TGF-β, play a role in excessive collagen production.•Recent studies have supported a role for Fibronectin Extra Domain A (Fn-EDA) which is markedly upregulated in keloids.•Identification of pathways involved in matrix accumulation allows development of targeted therapies for fibrotic diseases.