**Core Concept**
The patient's symptoms suggest a systemic condition that affects the skin and mucous membranes, characterized by scarring alopecia, nail changes, and hypopigmented macular lesions. This presentation is classic for a condition that involves the immune system's attack on the body's own tissues.

**Why the Correct Answer is Right**
The patient's symptoms are consistent with **Pitriasis Alba-like variant of Pityriasis Versicolor (Malassezia spp.)**, which is a superficial fungal infection. However, the presence of scarring alopecia and hypopigmented macular lesions suggests an underlying autoimmune component. The condition is thought to be related to a **cell-mediated immune response** against the fungal antigens, leading to inflammation and tissue damage. The involvement of oral mucosa and nail changes further supports this diagnosis.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not explain the scarring alopecia and hypopigmented macular lesions, which are not typical of this condition.
* **Option B:** This option is incorrect because it does not account for the involvement of oral mucosa and nail changes, which are characteristic of the condition described.

**Clinical Pearl / High-Yield Fact**
The Pitriasis Alba-like variant of Pityriasis Versicolor can be distinguished from other conditions by its characteristic **scarring alopecia** and **hypopigmented macular lesions**. This condition requires a high index of suspicion and careful examination of the skin and mucous membranes.

**Correct Answer: D.**