Skin mapping for the classification of generalized morphea.

Background: Generalized morphea lacks cohesive clinical features, limiting its clinical and investigative utility.

Objective: We sought to use computerized lesion mapping to objectively subtype morphea.

Methods: We conducted a 2-part cross-sectional study. In part 1, we created a discovery cohort of patients with generalized morphea of whom lesion maps were created to characterize subsets. Clinical and demographic features were compared between proposed subsets to determine if they identified clinically relevant differences. In part 2, we created a validation cohort to determine if proposed criteria were applicable to different individuals.

Results: A total of 123 patients with generalized morphea were included. Mapping produced 2 distribution patterns that encompassed the majority in both cohorts: isomorphic (areas of skin friction) and symmetric (symmetrically distributed on trunk/extremities). In the discovery cohort, the isomorphic subset was older (55.6 ± 12.7 vs 42.2 ± 20.1 years, P < .001), all female (30/30 vs 38/43, P = .05), and more often had lichen sclerosus changes (12/43 vs 8/43, P = .02); involvement of the reticular dermis, subcutaneous fat, and/or fascia was more common in symmetric (10/43 vs 1/30) (P = .02). These features persisted in the validation cohort.

Limitations: Single cohort was a limitation.

Conclusions: Symmetric and isomorphic subsets possess distinctive demographic and clinical features, suggesting they more accurately define the phenotype of generalized morphea. Consideration should be given to revising classification.