Okay, let's tackle this question about the differences between acne rosacea and acne vulgaris. First, I need to recall the key features of each condition. Acne vulgaris is the typical teenage acne, right? It involves comedones, papules, pustules, and sometimes cysts. It's more common in adolescents due to hormonal changes. On the other hand, acne rosacea is more of an adult condition, usually affecting the central face with erythema, telangiectasia, and sometimes pustules. But wait, both can have pustules, so that's a point of confusion.

The core concept here is distinguishing the clinical features and demographics of these two skin conditions. Both are chronic but have different presentations. The question is likely testing on features like age of onset, lesions, distribution, and associated symptoms.

For the correct answer, I need to identify which option highlights these differences. Let's say the correct answer is about the presence of comedones in acne vulgaris versus their absence in rosacea. That's a key differentiator. Also, the age groups: acne vulgaris in teens, rosacea in middle-aged adults. Another point is the distribution—rosacea is central face, while acne vulgaris can be more widespread.

Now, the wrong options. If one of them mentions comedones in both, that's incorrect because rosacea doesn't have comedones. Another wrong option might confuse the age groups. Maybe an option says that both have the same treatment, which is not true. Treatments differ: topical antibiotics for rosacea, retinoids for acne vulgaris.

The clinical pearl here is to remember that comedones are exclusive to acne vulgaris. Also, rosacea has flushing and telangiectasias. Students often mix up these features, so emphasizing the key differences in presentation and demographics is important for exams.

Putting it all together, the correct answer should highlight the presence of comedones in acne vulgaris and their absence in rosacea, along with age and lesion differences.

**Core Concept**
Acne vulgaris and acne rosacea are distinct dermatological conditions with different pathophysiologies, demographics, and clinical features. Acne vulgaris is characterized by comedones, papules, pustules, and cysts due to sebaceous gland hyperactivity and *C. acnes* colonization, while acne rosacea involves chronic inflammation, vascular abnormalities, and absence of comedones, often triggered by environmental factors.

**Why the Correct Answer is Right**
The correct answer identifies **comedones as exclusive to acne vulgaris**, a hallmark differentiating it from rosacea. Acne vulgaris involves keratinocyte hyperproliferation and follicular occlusion, leading to open/closed comedones. Rosacea lacks comedones, instead presenting with erythema, telangiectasias, and inflammatory papules/pustules due to immune dysregulation and vascular hyperreactivity. Age of onset also differs: acne vulgaris typically affects adolescents, while rosacea occurs in adults over 30.

**Why Each Wrong Option is Incorrect**
**Option A:** Suggests both conditions involve comedones—incorrect, as rosacea lacks comedones.
**Option B:** Claims rosacea is more common in adolescents—false; rosacea peaks in middle-aged adults.
**Option C:** States pustules are absent in rosacea—

✓ Correct Answer: D. Absence ofcomedone