Correlation of clinical and pathologic evaluation of scarring alopecia

Background: Differentiating scarring and nonscarring alopecia poses a diagnostic dilemma for clinicians, with histopathology used to distinguish. The extent to which dermatologists are able to clinically classify alopecia has not been evaluated. Methods: A retrospective study of pathology reports on 458 patients was used to calculate a kappa coefficient to correlate clinical presence of scarring or nonscarring alopecia to histopathologic presence of scarring or nonscarring. A multivariate analysis was performed to assess for associations with scarring. Results: The kappa correlation coefficient was 0.59 (P < 0.0001), indicating moderate agreement and varied by race and sex. There were 15 times higher odds of making the clinical diagnosis of scarring alopecia (OR 14.64 95% CI [8.64–24.18]; P < 0.001), and this increased with age. Conclusions: These results suggest that clinical exam is moderately reliable in distinguishing between scarring and nonscarring alopecia. Our results highlight the need for education and diagnostic schemata for evaluation of alopecia based on gender and in skin of color.