What feature distinguishes acne rosacea from typical acne vulgaris?

The distinguishing feature of acne rosacea compared to typical acne vulgaris is the absence of blackheads. Acne vulgaris is characterized by the presence of comedones, which include open (blackheads) and closed (whiteheads) lesions. These forms of acne are primarily associated with hormonal changes, excessive sebum production, and clogged pores.

In contrast, acne rosacea does not present with blackheads. Instead, it typically manifests with persistent redness, flushing, visible blood vessels, and papules or pustules on the face, particularly the cheeks, nose, and forehead. The inflammatory nature of rosacea is different from the pathogenic characteristics of acne vulgaris.

Focusing on the other options, the presence of cysts is common with severe cases of acne vulgaris but is not a hallmark of rosacea. Severe itching is not a prominent symptom of either condition, although it may occasionally occur in rosacea due to inflammation. The term "hormonal acne" often refers to acne vulgaris, particularly in patients influenced by hormonal changes, and does not apply to rosacea. Therefore, the absence of blackheads is the key differentiating factor between these two conditions.