**Core Concept**
Keloids are a type of raised, thickened scar that forms after skin injury, involving an abnormal wound healing response. This is characterized by excessive collagen deposition, leading to a firm, rubbery, and often itchy lesion that can be painful.

**Why the Correct Answer is Right**
Keloids result from an imbalance between collagen synthesis and degradation, with an overproduction of type I and type III collagen. This is mediated by the activation of fibroblasts, which release growth factors such as platelet-derived growth factor (PDGF) and transforming growth factor-beta (TGF-β). These growth factors stimulate the proliferation and differentiation of fibroblasts into myofibroblasts, leading to increased collagen production and the formation of a keloid.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because keloids are not caused by an autoimmune response, but rather by an abnormal wound healing response involving excessive collagen deposition.

**Option B:** This option is incorrect because keloids are not typically associated with a decrease in collagen degradation, but rather an overproduction of collagen.

**Option C:** This option is incorrect because keloids are not primarily caused by a genetic predisposition, although there may be a familial component.

**Clinical Pearl / High-Yield Fact**
To differentiate keloids from hypertrophic scars, look for the presence of a distinct border, a firm texture, and a raised appearance, as these are characteristic features of keloids.

**Correct Answer:** D.