**Core Concept**
Keloids are a type of raised, thick scarring that occurs after skin injury, characterized by an abnormal growth of collagen and other skin components. This excessive collagen deposition leads to the formation of a firm, smooth, and often itchy or painful nodule that can extend beyond the original wound margins.

**Why the Correct Answer is Right**
The correct answer is related to the pathophysiology of keloids, which involves an exaggerated wound healing response. This response is mediated by an overproduction of collagen and other extracellular matrix components, driven by the prolonged activation of fibroblasts and the release of growth factors such as platelet-derived growth factor (PDGF) and transforming growth factor-beta (TGF-β). The increased collagen synthesis and deposition in keloids are thought to result from an imbalance between collagen production and degradation, leading to a net accumulation of collagen fibers.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because keloids are not caused by an autoimmune response, as is seen in conditions such as lupus or rheumatoid arthritis.
**Option B:** This option is incorrect because keloids are not simply a result of poor wound care or delayed wound healing, although these factors may contribute to the development of keloids in some cases.
**Option C:** This option is incorrect because keloids are not typically characterized by a decrease in collagen production, but rather by an excessive accumulation of collagen fibers.

**Clinical Pearl / High-Yield Fact**
It's essential to note that keloids can be difficult to treat and may require a combination of topical and intralesional corticosteroids, silicone gel or sheeting, and surgical excision. In some cases, laser therapy or radiotherapy may also be considered.

**Correct Answer: D. Keloids are characterized by an abnormal growth of collagen and other skin components.**