Medical history of the representation of rosacea in the 19th century.

Throughout the 1800s, clinical illustrations helped to formalize what was then the recently developed field of dermatology. Knowledge of skin diseases was given new dimension as artists and clinicians alike strove to accurately document the physical characteristics of numerous dermatoses. Introduction of novel processes and refined techniques advanced the clinical use of disease images. The increasingly superior quality of these images aided in the early distinction between rosacea and acne. This article highlights these illustrative contributions in dermatology, and includes key images that serve as a road map to early clinical understanding of skin diseases.