Unravelling the paradox of reverse chronology in follicular vitiligo

Abstract

AbstractFollicular vitiligo is a recently proposed variant of vitiligo, characterized by a primary or predominant depigmentation of hair follicles with no to limited involvement of the interfollicular skin in a nonsegmental distribution, in contrast to vitiligo vulgaris where the opposite predominance and sequence of progression is seen. It is difficult to recognize follicular vitiligo when it presents as isolated leukotrichia without interfollicular skin depigmentation, and the diagnosis is often made in hindsight after the interfollicular skin becomes involved. In follicular vitiligo, the immune response is primarily directed towards hair follicle melanocytes, in contrast to vitiligo vulgaris, in which antigenically distinct melanocytes of the interfollicular skin are targeted. Rapid graying of hair, frequent involvement of the terminal hair of the scalp, eyelashes, and beard, proposed autoimmune response against hair follicle melanocytes, and a proposed loss of immune tolerance of hair follicle melanocytes are the features shared by follicular vitiligo and alopecia areata. Targeted agents such as JAK–STAT pathway inhibitors which have been shown to work in both alopecia areata and vitiligo vulgaris can be useful in the progressive stage of follicular vitiligo.