Follicular leukoderma is an early step in the course of ordinary vitiligo: A new hypothesis

Abstract

Background Hair follicle is the primary target of many skin diseases. Vitiligo is a well-known autoimmune disease where the basal melanocytes of epidermis are attacked by the immunological reactions. Recently we had shown that the ordinary vitiligo might start initially in the hair follicles.   Methods Ninety patients with vitiligo having follicular leukoderma were involved during the period from 2014-21. Clinical and Wood’s lamp examination were done to confirm vitiligo and exclude other hypopigmented diseases. Also, Skin biopsies for 10 cases with white follicular lesions and black hair were performed and stained with Haematoxylin-Eosin and immunohistochemical stains (HMB-45 and melan A) to evaluate histopathological changes.   Results 90 patients were analysed. Their ages ranged from 4 - 40 years with a mean of 20±4 years. Clinical and Wood’s lamp examination showed that all patients had follicular white minute macules in early course of the disease that gradually coalesced into larger white macules and patches at the same sites. Histopathological examination including using immunohistochemical stain showed absent melanocytes in the hair follicle infundibulum and the adjacent basal layer of epidermis, perifollicular lymphocytic infiltrates and areas of focal invasion of follicular epithelium and the surrounding epidermis. In addition, superficial and to a lesser extent deep perivascular lymphocytic infiltrates were observed.   Conclusion Ordinary vitiligo initially starts as follicular leukoderma without necessarily causing leukotrichia, then these macules coalesce into larger vitiliginous patches.   Key words Follicular leukoderma, vitiligo, hypothesis.