**Core Concept**
Primary cutaneous disorders are conditions that originate in the skin itself, without systemic involvement. These conditions are often characterized by localized skin lesions or manifestations.

**Why the Correct Answer is Right**
The correct answer is a systemic disorder that presents with skin manifestations. This means that the underlying pathophysiology involves a systemic process, rather than a primary skin disorder. For example, some systemic conditions like lupus erythematosus can present with skin lesions, but the primary pathology is in the immune system.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is a primary cutaneous disorder, often caused by a viral infection that affects the skin, leading to characteristic lesions.
* **Option B:** This option is a primary cutaneous disorder, characterized by abnormal keratinization of the skin, leading to scaly lesions.
* **Option C:** This option is a primary cutaneous disorder, often caused by an autoimmune response that targets the skin, leading to blistering lesions.

**Clinical Pearl / High-Yield Fact**
When differentiating between primary and secondary cutaneous disorders, remember the "ABCDE" rule: A - Autoimmune, B - Bacterial, C - Cutaneous, D - Dermatological, and E - Endocrine. This rule can help you quickly identify the underlying cause of skin manifestations.

**Correct Answer:** D.