**Core Concept**
Moth-eaten alopecia is a type of non-scarring hair loss characterized by diffuse thinning of hair with a distinctive "moth-eaten" appearance. This condition is often associated with autoimmune disorders, particularly lupus erythematosus.

**Why the Correct Answer is Right**
Moth-eaten alopecia is a classic feature of discoid lupus erythematosus (DLE), an autoimmune skin condition that primarily affects the scalp. The pathogenesis of DLE involves a combination of genetic predisposition, sun exposure, and immune system dysregulation, leading to inflammation and scarring of the scalp. The characteristic "moth-eaten" appearance is due to the diffuse thinning of hair and the presence of scarring alopecia.

**Why Each Wrong Option is Incorrect**
* **Option A:** Traction alopecia is a type of non-scarring hair loss caused by repetitive mechanical stress, typically seen in individuals with tight hairstyles. It does not have a "moth-eaten" appearance.
* **Option B:** Alopecia areata is an autoimmune condition characterized by patchy hair loss, but it does not typically present with a diffuse, "moth-eaten" appearance.
* **Option C:** Trichotillomania is a psychological condition characterized by compulsive hair pulling, leading to patchy hair loss. It is not associated with a "moth-eaten" appearance.

**Clinical Pearl / High-Yield Fact**
Moth-eaten alopecia is a characteristic feature of discoid lupus erythematosus (DLE) and should prompt a thorough investigation for underlying autoimmune disorders, particularly in patients with a history of skin lesions or sun exposure.

**Correct Answer:** D. Discoid lupus erythematosus