Linear Lichen Planopilaris of the Trunk: First Report of a Case

Abstract

Background:

Lichen planopilaris (LPP) is believed to be a follicular variant of lichen planus that affects pilosebaceous units, mainly of the scalp. An extremely rare variant of LPP is a linear form, which follows the lines of Blaschko. Of the five previously documented cases of linear LPP, all were limited to the face.

Objective:

We report the case of a 34-year-old male who presented with a nonpruritic eruption on the trunk consisting of erythematous, keratotic, folliculocentric papules following Blaschko's lines.

Results:

Biopsy revealed lichenoid and interface dermatitis involving the basilar epidermis and hair follicles, as well as apoptotic keratinocytes, consistent with LPP.

Conclusion:

This represents the first documented case of LPP, following the Blaschko's lines, in a nonfacial distribution.