**Core Concept**
Hypopigmented lesions refer to areas of skin that are lighter than the surrounding skin, resulting from a reduction or absence of melanin. This can occur due to various factors, including genetic disorders, infections, or autoimmune conditions.

**Why the Correct Answer is Right**
The correct answer involves conditions that affect the production or distribution of melanin, leading to hypopigmented lesions. For instance, conditions like pityriasis versicolor, caused by the yeast Malassezia, affect the skin's ability to produce melanin, resulting in hypopigmentation. Another example is vitiligo, an autoimmune disease where the immune system attacks and destroys melanocytes, leading to white patches on the skin.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not directly relate to hypopigmentation. Conditions like eczema or psoriasis may cause skin lesions, but they are typically characterized by erythema (redness) rather than hypopigmentation.

**Option B:** This option is incorrect as it is more likely to cause hyperpigmentation rather than hypopigmentation. Melasma, for instance, is a condition characterized by dark patches on the skin, often triggered by hormonal changes or sun exposure.

**Option C:** This option is incorrect as it is not directly related to hypopigmentation. Acne vulgaris is a skin condition characterized by comedones (blackheads and whiteheads), papules, and pustules, but it does not typically cause hypopigmentation.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that hypopigmented lesions can be a sign of underlying conditions that require prompt medical attention. Conditions like pityriasis versicolor or vitiligo may be easily treatable with topical medications or phototherapy, but ignoring these lesions can lead to further complications.

**Correct Answer: D. Vitiligo. Vitiligo is a chronic autoimmune condition characterized by the loss of melanocytes, resulting in hypopigmented lesions.**