Which condition is characterized by the "butterfly rash"?

The butterfly rash is a distinctive facial rash that appears across the cheeks and bridge of the nose, resembling the shape of a butterfly. This rash is most commonly associated with systemic lupus erythematosus (SLE), an autoimmune condition that can affect multiple organ systems. The presence of the butterfly rash is significant because it is one of the hallmark symptoms used in diagnosing SLE, alongside other clinical features and laboratory findings.

In systemic lupus erythematosus, the rash may be triggered or exacerbated by sun exposure, highlighting the photosensitivity often seen in patients with this condition. This characteristic helps differentiate SLE from other dermatological or systemic conditions.

While psoriasis is known for its well-defined plaques and scales, dermatitis herpetiformis is characterized by itchy, blistering lesions often associated with gluten sensitivity, and rosacea presents with facial flushing and erythema without the distinct butterfly pattern. Thus, the association of the butterfly rash distinctly with systemic lupus erythematosus clearly establishes the rationale behind identifying it as the correct answer in this context.