**Core Concept**
The case describes a child with a hypo-pigmented anesthetic patch on the face, which suggests a condition affecting the peripheral nerves or the skin. This presentation is characteristic of a specific dermatological condition that involves the loss of sensation and skin pigmentation.

**Why the Correct Answer is Right**
The most likely diagnosis is **leprosy** (Hansen's disease), a chronic bacterial infection caused by *Mycobacterium leprae*. Leprosy affects the peripheral nerves, leading to sensory loss and skin anesthesia. The hypo-pigmented skin patches are due to the loss of melanocytes and the disruption of the skin's pigmentary function. The anesthetic patches are a result of nerve damage, which impairs the transmission of sensory information.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect as it does not match the description of the case. The condition described is not consistent with a viral infection like chickenpox.
* **Option B:** This option is incorrect as it does not fit the presentation of hypo-pigmented anesthetic patches. Vitiligo is a condition characterized by the loss of skin pigment, but it does not affect sensation.
* **Option C:** This option is incorrect as it does not match the description of the case. The condition described is not consistent with a bacterial infection like impetigo.

**Clinical Pearl / High-Yield Fact**
Leprosy is a notifiable disease, and early diagnosis is crucial to prevent the spread of the infection. The World Health Organization (WHO) recommends a multi-drug therapy regimen for leprosy, which includes rifampicin, clofazimine, and dapsone.

**Correct Answer:** C. Leprosy (Hansen's disease)