Interface dermatitis along Blaschko's lines

Abstract

Linear dermatoses are fascinating entities that likely reflect embryologically derived cutaneous mosaicism, even when they occur after childhood. Adult blaschkitis is a rare, relapsing inflammatory dermatitis that most often presents in middle age. It presents clinically as a pruritic eruption of linear papules, vesicles and plaques, and is most commonly found to have features of spongiotic dermatitis on pathology. However, the clinical and histopathologic presentation of lichen striatus in adults may be similar to those of adult blaschkitis. A case in which 'blaschkitis' was suspected clinically is presented, in which the biopsy showed non-characteristic microscopic features resembling erythema multiforme--a finding rarely reported in the literature to date. We present this case and a brief review of the most commonly acquired linear eruptions following Blaschko's lines with the goal of expanding the histopathologic findings that may be encountered in adult blaschkitis. Moreover, the clinical and histopathologic overlap between the entities of blaschkitis and lichen striatus is explored, acknowledging that these entities may exist on a clinicopathologic spectrum. In the diagnosis of linear eruptions, clinicopathologic correlation is important for arriving at an accurate final diagnosis.

Compound-honeysuckle-induced drug eruption with special manifestations: A case report

“…The histopathology of Blaschko line dermatitis is mainly characterized by spongiform dermatitis[ 20 - 22 ], and there are also reports of interfacial dermatitis[ 23 ]. The histopathology of our patient showed changes in spongiform dermatitis, as well as interfacial dermatitis.…”

Unilateral Atrophic Hyperpigmentation

“…Inflammatory or palpable lesions have never been mentioned in this patient. 8 Incontinentia pigmenti could easily be excluded clinically as well as histologically. It usually starts with a blistering inflammation of the skin evolving through 4 stages ending with postinflammatory linear hyperpigmentation with melanophages in the upper dermis.…”

A linear lesion in a child with atopic dermatitis: Not a coincidence

“…Superimposed linear atopic dermatitis may be more common than reported. This segmental distribution may pass unremarked, and cases of segmental dermatitis have been diagnosed with and published as other conditions, mainly lichen striatus and blaschkitis, especially when typical, symmetric AD lesions and/ or extracutaneous signs of atopy are absent.…”