Keloid scars are characterized by which type of collagen?

Keloid scars are classified by their composition, primarily featuring an abundance of disorganized type 1 and type 3 collagen. In wound healing, type 3 collagen is typically prominent in the early stages and later gets replaced by type 1 collagen as the scar matures. However, in keloids, an excessive and disorganized deposition of both type 1 and type 3 collagen occurs, leading to the characteristic thick, raised, and firm nature of the scars.

Keloids result not just from an abnormal healing process but also from genetic predisposition, leading to overproduction of collagen beyond what is necessary for normal tissue repair. This excessive collagen accumulation signifies a pathological response, contrasting with normal wound healing where collagen would be correctly organized and remodeled over time.

Understanding this alteration in collagen type and organization is crucial for recognizing the distinct features of keloids compared to other forms of scarring or fibrosis, which typically show a more ordered and balanced arrangement of collagen fibers.