**Core Concept**
Keloid scars are a type of raised, thickened scar tissue that can form after a skin injury. They result from an excessive wound-healing response, characterized by an overproduction of collagen. This condition is often influenced by genetic and hormonal factors.

**Why the Correct Answer is Right**
Keloid scars are believed to result from an imbalance in the normal wound-healing process, with an overexpression of transforming growth factor-beta (TGF-β) and other growth factors. The increased collagen deposition in keloid scars is mediated by the activation of fibroblasts, which produce excessive amounts of collagen type I. This leads to a thickened, raised scar that can cause discomfort and cosmetic concerns.

**Why Each Wrong Option is Incorrect**
**Option A:**
Keloid scars are not caused by an autoimmune response, as they are not the result of an immune system reaction against the body's own tissues.

**Option B:**
Keloid scars are not a result of poor wound care or hygiene, as they can occur even with proper wound management. Instead, they are influenced by genetic and hormonal factors.

**Option C:**
Keloid scars are not a type of hypertrophic scar, although both conditions share some similarities. Hypertrophic scars are typically smaller and more raised than keloid scars.

**Clinical Pearl / High-Yield Fact**
Keloid scars can be triggered by various factors, including skin injuries, acne, and certain medical procedures. It's essential for clinicians to recognize the risk factors and take preventative measures to minimize the formation of keloid scars.

**Correct Answer:** D.