Clinical Severity and Outcome Measures in Seborrheic Dermatitis: A Systematic Review

INTRODUCTION: Seborrheic dermatitis (SD) is a common chronic inflammatory dermatosis associated with substantial symptom burden and impaired quality of life. Despite increasing interest in development of advanced therapies for SD, standardization of outcome measures appears limited. We sought to understand how disease severity, symptoms, and quality of life are measured in seborrheic dermatitis clinical studies. METHODS: We conducted a systematic review of clinical studies (both interventional and observational) assessing SD severity and treatment response. Eligible studies were identified through comprehensive database searches (Embase, PubMed, Scopus, Cochrane Database of Systematic Reviews, CINAHL Complete) and screened according to predefined inclusion criteria. Outcome measures were categorized by framework (clinician, patient, or combined), assessed domain(s), instrument type, and temporal, geographic, and study design characteristics. RESULTS: A total of 215 studies were included in the final analysis. Most studies relied primarily on clinician-reported outcomes (ClinROs), with fewer than half incorporating any patient-reported outcomes (PROs). Investigator-defined ClinROs predominated, while formally named, SD-specific indices, such as the Seborrheic Dermatitis Area and Severity Index, were infrequently used. Core clinical signs, including erythema and scaling, were consistently assessed across multiple study decades, whereas subjective symptoms and quality-of-life domains were measured less consistently. Although the use of combined ClinRO + PRO frameworks increased over time, clinician-centered assessments remained dominant across study designs and regions. CONCLUSION: Outcome measurement in seborrheic dermatitis research is heterogeneous and remains predominantly clinician-centered, with limited validation and inconsistent use of validated ClinRO or PRO instruments. Greater standardization of outcome frameworks and broader integration of PROs may improve comparability and better capture patient-relevant disease burden in SD clinical research.