Quantitative histopathologic findings of Erythromelanosis follicularis faciei et colli

Background: Even though only 33 cases of Erythromelanosis follicularis faciei et colli (EFFC) have been reported around the world, there have been no quantitative clinicopathological studies yet. The purpose of this study is to examine quantitatively clinical and histopathological evaluations of EFFC using image analysis system. Method: Clinical grading of its severity was assessed. Many parameters of the horny layer, granular layer, epidermis and the dermal components were measured and compared to controls by image analysis. The correlation between the histological findings and clinical grading was assessed. Result: Thickness and compactness of the horny layer was significantly increased in EFFC. There were no significant differences in the number of melanocytes and severity of pigmentation between EFFC and controls; however, melanization was slightly increased in EFFC. The percent area of the superficial blood vessels was significantly increased and correlated with visual grading of erythema. Diameters of hair shafts and outer root sheaths, and thickness of inner root sheaths were decreased. Basal layer pigmentation was correlated with the clinical features of pigmentation. Conclusion: This study supported the findings of hyperkeratosis and dilatation of superficial dermal blood vessels in EFFC. The pigmentation of the basal layer and the percent area of the inner spaces of the superficial dermal blood vessels may reflect the clinical severity more than the other parameters. Although follicular plugging is a characteristic clinical feature of EFFC, enlargement of hair follicles and hair shafts were not characteristic pathologic changes EFFC in our study.