Coexistence of systemic and localized scleroderma: a systematic literature review and observational cohort study.

SSc and localized sclerosis (LoS) are considered clinically distinct entities. We describe herein the coexistence of SSc and LoS by both a systematic literature review and an observational cohort study of unselected SSc patients. Original studies documenting the coexistence of SSc and LoS were identified in three electronic databases by means of a systematic literature search according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Additionally, the coexistence of SSc and LoS was studied in a prospective cohort of SSc patients visiting the Ghent University Scleroderma Unit for their yearly follow-up visit between January 2018 and January 2019. Five studies were finally included for quality appraisal and data extraction. The coexistence of SSc and LoS ranged between 2.4 and 7.4%. RP, scleroderma pattern on nailfold videocapillaroscopy (NVC) and the presence of SSc-specific antibodies were commonly observed in coexistent cases. Additionally, coexistence of SSc and LoS was found in 8/296 (2.7%) consecutive SSc patients of the Ghent University Scleroderma Unit. RP was present in 6/8 coexistent cases; a scleroderma pattern on NVC was observed in all coexistent cases, and SSc-specific antibodies (i.e. cenp-B) were found in 4/8 coexistent cases. This is the first systematic literature review with additional cohort evaluation investigating the coexistence of SSc and LoS. A relatively high overlap of SSc and LoS was revealed, which is peculiar because both are rare diseases.