BACKGROUND: The absence of specific histological or serological markers, the gaps in understanding the aetiology and pathophysiology of rosacea, and the broad diversity in its clinical manifestations has made it difficult to reach international consensus on therapy guidelines. OBJECTIVES: The main objective was to highlight the global diversity in current thinking about rosacea pathophysiology, classification and medical features, under particular consideration of the relevance of the findings to optimization of therapy. METHODS: The article presents findings, proposals and conclusions reached by the ROSacea International Expert group (ROSIE), comprising European and US rosacea experts. RESULTS: New findings on pathogenesis provide a rationale for the development of novel therapies. Thus, recent findings suggest a central role of the antimicrobial peptide cathelicidin and its activator kallikrein-5 by eliciting an exacerbated response of the innate immune system. Cathelicidin/kallikrein-5 also provide a rationale for the effect of tetracyclines and azelaic acid against rosacea. Clinically, the ROSIE group emphasized the need for a comprehensive therapy strategy - the triad of rosacea care - that integrates patient education including psychological and social aspects, skin care with dermo-cosmetics as well as drug- and physical therapies. Classification of rosacea into stages or subgroups, with or without progression, remained controversial. However, the ROSIE group proposed that therapy decision making should be in accordance with a treatment algorithm based on the signs and symptoms of rosacea rather than on a prior classification. CONCLUSION: The ROSIE group reviewed rosacea pathophysiology and medical features and the impact on patients and treatment options. The group suggested a rational, evidence-based approach to treatment for the various symptoms of the condition. In daily practice this approach might be more easily handled than prior subtype classification, in particular since patients often may show clinical features of more than one subtype at the same time.