ImportanceAssessment of type, severity, and impact of dermatologic adverse events (DAEs) necessitates well-developed and validated clinician-reported outcome measures (ClinROMs) and patient-reported outcome measures (PROMs) that evaluate concepts specific to mucocutaneous toxic effects and that allow appropriate interpretation and comparison of DAEs across trials.ObjectiveTo evaluate heterogeneity and quality of ClinROMs and PROMs used to assess DAEs from systemic cancer therapy.Evidence ReviewTwo systematic reviews were conducted by searching PubMed and Embase databases from inception through March 7, 2023, and April 12, 2023. The first search included randomized clinical trials and observational studies reporting systemic cancer treatment–induced DAEs assessed by a ClinROM or PROM. The second included studies evaluating measurement properties of frequently used ClinROM and PROM instruments. The Consensus-Based Standards for the Selection of Health Measurement Instruments risk of bias tool was used to evaluate methodologic quality of validation assessments.FindingsA total of 395 studies were included. The Common Terminology Criteria for Adverse Events (CTCAE) was utilized in 331 studies meeting inclusion criteria (83.8%). At least 1 skin-related PROM was infrequently utilized in systemic chemotherapy clinical trials (79 studies [20.0%]). Most frequently utilized PROMs were the Dermatology Life Quality Index (DLQI; 34 studies [8.6%]) and Skindex-16 (20 studies [5.1%]). Among studies capturing DAEs, 115 (29.1%) reported a nondescript term (ie, rash) as the only DAE. Eight studies described 44 property assessments of the CTCAE, DLQI, and Skindex. There were no studies evaluating content validity, intrarater reliability, or measurement error for the CTCAE, DLQI, or Skindex. There were no studies evaluating structural validity, internal consistency, and responsiveness of DLQI or Skindex. Interrater reliability and responsiveness were each assessed for 1 DAE-related component of the CTCAE. Construct validity for CTCAE, DLQI, and Skindex was evaluated in 29 (65.9%), 3 (6.8%), and 9 (20.5%) assessments, respectively.Conclusions and RelevanceIn this systematic review, there was a narrow spectrum of ClinROMs and PROMs with limited validity for the measurement of DAEs in the context of systemic chemotherapy interventions in clinical trials. Report of trial DAEs often had low morphologic specificity and meaning. Based on existing gaps in measurement and report of DAEs, a frequent and impactful adverse event to chemotherapy, the framework for evaluating cutaneous toxic effects in oncology trials may need collaborative reevaluation.