Simultaneous Lichen Striatus in Siblings along the Same Blaschko Line

Abstract

Lichen striatus (LS) is an asymptomatic, spontaneously resolving linear dermatosis consisting of 2 to 4 mm flat topped papules following the lines of Blaschko. Two siblings presented with a simultaneous occurrence of LS along the same Blaschko line of the left upper extremity. Only four other cases of a simultaneous occurrence of LS in related siblings have been reported, but none of these have occurred in the same extremity. Although 10 years have passed since the last case report of this unique concurrent familial eruption, few discoveries have been made regarding its etiology. Several theories have been proposed including environmental agents, cutaneous injury, viral infection, hypersensitivity, and genetic predisposition. These theories are discussed along with retrotransposons, a possible new explanation for the pathogenesis of this and other Blaschko line disorders.

Cryotherapy for Lichen Striatus in an Adult – a Case Report

“…Th us, Racette et al, hypothesize that individuals with LS are predisposed with partially silenced genomic transposable elements which are methylated or demethylated by an immunologic reaction to an infection. Th e infection acts only as an initiator of the aberrant cell-mediated immune response by creating a cellular alteration (7). Recently reported association of LS with Blaschkoid pityriasis rosea in the same location, also supports this concept (8).…”

“…A recent report on the unique simultaneous occurrence of LS in two related siblings (one suff ering from recurrent otitis media) along the same BL, supports the infectious and genetic components in the development of LS (7). Th is report also supports the latter theory of epigenetic mosaicism, since this theory is based strictly on familial occurrence of LS, in contrast to the former, which supports somatic mutations with occurrence by chance, when familial incidence is improbable (7). Although familial occurrences are extremely rare, it seems most likely that diff erent endogenous or exogenous factors may lead to the unmasking of tolerance to an abnormal keratinocyte clone in apparently healthy,…”

“…Moreover, the lack of viral particles in the lesions reported by some authors substantiates the hypothesis that infection or other exogenous triggers (e.g., environmental agents, cutaneous injury and hypersensitivity reaction) need only to initiate the cell-mediated immune response. Th e absence of prodromal symptoms in our patient as in most cases, does not exclude the possibility of asymptomatic illness triggering LS (7). Th e occurrence of LS after allogenic stem cell transplantation was hypothesized to be an unusual form of localized, chronic graft-versus-host disease (9).…”

Lichen striatus and blaschkitis: reappraisal of the concept of blaschkolinear dermatoses

“…1,2 Rarely, genodermatoses related to an X-chromosomal mosaicism occurring in females only also exhibit a linear arrangement of skin symptoms following Blaschko's lines (incontinentia pigmenti and focal dermal hypoplasia). 3,4 These theories are discussed along with retrotransposons, a possible new explanation for the pathogenesis of this and other Blaschko line disorders. 1 Several theories have been proposed, including environmental agents, cutaneous injury, viral infection, hypersensitivity and genetic predisposition.…”

“…Additionally, there are various common inflammatory skin diseases without a genetic background which sometimes present as linear dermatoses [linear lichen planus, linear lichen nitidus, linear scleroderma, linear (zosteriform) vitiligo, linear fixed drug eruption and linear chronic lupus erythematosus]. 4 Cutaneous antigenic mosaicism, the expression of which might be induced by a viral infection, could trigger this localized inflammatory T-cell response. 3,4 These theories are discussed along with retrotransposons, a possible new explanation for the pathogenesis of this and other Blaschko line disorders.…”