Several cases with similar clinical and histologic features, but with generalized atopic dermatitis or another atopic background were diagnosed as linear atopic dermatitis or mosaic atopic eczema. In our case, as in other cases reported as ‘acquired Blaschko dermatitis’, there was no personal or family history of atopic dermatitis. Some authors suggested that these eruptions may present abortive forms of atopic dermatitis caused by mosaicism with one wild-type and one pathogenic allele in the affected Blaschko line and two wild-type alleles in the remaining tissues. But so far the exact relationship still remains uncertain, so the term ‘acquired Blaschko dermatitis’ would be better in cases without systemic atopy. Definite diagnosis is only possible on the background of pronounced systemic atopy.
Linear lichen planus, affecting 0.24% to 0.62% of all patients with lichen planus, can also show the blaschkolinear pattern. However, clinical histology reveals a lichenoid tissue reaction underlying an acanthotic epidermis with an accentuated granular
layer. Clinical features, such as mucosal involvement, nail changes, or concurrent classic lichen planus-like lesions also help differentiate from acquired Blaschko dermatitis. cialis soft tabs
Recently, there has been a trend to include acquired Blaschko dermatitis as an adult-onset variation of lichen striatus, as lichen striatus exhibits many variable chameleon-like features clinically and histologically. But despite some over- laping conditions, they can be easily differentiated. Lichen striatus is a more common condition and generally affects children with an average age of 3 years. It consists of small inflammatory papules, rarely vesicles with one or few lines along Blaschko’s lines unilaterally on a limb. The lesions spontaneously disappear within a few months and usually do not relapse. Non-specific spongiotic changes can be observed occasionally, but focal, band-like lymphocytic infiltration in the dermis is the most characteristic finding. In contrast, adult Blaschkitis or acquired Blaschko dermatitis is a rare condition, generally affecting adults with a mean age of 40 years and consisting of papules and vesicles with multiple lines along Blaschko’s lines uni- or bilaterally, especially on the trunk. The prognosis has a rapid resolution, less than 2 months and usually relapses are without sequelae. Histologically, a spongiotic pattern is characteristic. In our case, clinical and histological features, except the unusual young age, fit acquired Blaschko dermatitis. Further cases should be collected to understand the nature of this new entity as a separate term, which should be differentiated with other dermatoses, especially lichen striatus.