Unusual Interface Dermatoses Distributed Along Blaschko's Lines in Adult Patients

Abstract

Linear dermatoses are unusual entities whose distribution reflects cutaneous mosaicism, even when they occur in adult life. Adult blaschkitis (AB) and lichen striatus (LS) always follow this peculiar distribution. Although usually referred to as distinct entities, the clinical and histopathological presentation of lichen striatus in adults may be similar to those of adult blaschkitis. Moreover, some cases with overlapping features between lichen striatus and linear lichen planus have been published, making precise diagnosis very difficult. Recently, the concept of a wide spectrum of blaschkolinear dermatoses with AB and LS located somewhere within it has been proposed but it has not gained general recognition. We report three cases of dermatoses following the lines of Blaschko in adults (two women and one male, ages 35, 50 and 56, respectively). They involved the upper extremity in two cases and the lower in the third. Clinically, they were interpreted as linear lichen planus or blaschkitis but, histopathologically, they showed features consistent with lichen striatus. Lesions subsided with topic steroids and/or tacrolimus ointment, they are an example of the significant overlapping between these three entities, demonstrating that they may exist on a spectrum both clinically and histopathologically and clinico-pathologic correlation is essential to achieve an accurate final diagnosis. A detailed review of previously published cases has also been made.

Positive Antinuclear Antibody and Blaschkoid Lichen Planus Pigmentosus

“…However, antinuclear antibody (ANA) was reported to be positive by indirect immunofluorescence using rat esophagus, in mucosal erosive lichen planus, in 40.42% of patients [ 2 ]. Blaschko’s lines (BL) were named after Alfred Blaschko, a German dermatologist in 1858-1922 [ 3 , 4 ]. They do not follow neural, vascular, or lymphatic pathways.…”

Adult Blaschkitis With Lichenoid Features and Blood Eosinophilia

“…There have been many reports of congenital and acquired dermatosis that trail BL. Congenital dermatoses located on BL are incontinentia pigmenti, epidermal nevus, linear nevus sebaceous, and focal dermal hypoplasia (Goltz syndrome) [3][4][5].…”

Blaschko Linear Acquired Inflammatory Skin Eruption (BLAISE) presenting as a paraneoplastic phenomenon

“…increasing relevance as recent studies have highlighted that adult blaschkitis and lichen striatus share overlapping clinical and histopathological features. [1][2][3] It also advantageously incorporates entities less commonly seen in a blaschkoid distribution, such as lichen planus, where differentiation may prove difficult. [2][3] We report a 79-year-old woman who presented with a multilinear papulosquamous eruption of 6 weeks' duration.…”

“…[1][2][3] It also advantageously incorporates entities less commonly seen in a blaschkoid distribution, such as lichen planus, where differentiation may prove difficult. [2][3] We report a 79-year-old woman who presented with a multilinear papulosquamous eruption of 6 weeks' duration. Examination revealed a strikingly symmetrical distribution along the lines of Blaschko involving bilateral upper limbs and trunk ( Fig.…”

“…With the exception of a subcorneal pustule, these were compatible with previously reported histopathological features of BLAISE. 2,3 Due to its asymptomatic nature, application of emollient only was recommended. Complete resolution followed in 4 weeks, during which time the bladder wall tumor had been resected.…”