Journal of Case Reports in Medical Science

Aims: Lichen striatus (LS) is an uncommon, benign, acquired inflammatory dermatosis that follows the lines of Blaschko and predominantly affects children; its occurrence in adults is exceptional. We report a case of truncal LS in a 30-year-old man and discuss its distinction from other adult-acquired blaschkolinear dermatoses.

Presentation of Case: A 30-year-old man with a family history of atopy presented with a non-pruritic papular eruption on the right side of the trunk, with no antecedent trauma, infection, drug intake or vaccination. Examination revealed numerous erythematous-violaceous papules distributed unilaterally along the lines of Blaschko in an inverted-U configuration without crossing the anterior midline. Dermoscopy showed an erythematous background with pigmentary incontinence. The remaining skin, mucous membranes and appendages were normal. Laboratory investigations were unremarkable, and histopathology demonstrated a lichenoid infiltrate consistent with LS.

Discussion: In adults, LS must be distinguished primarily from adult blaschkitis, linear lichen planus and linear psoriasis. Adult blaschkitis typically presents with pruritic papulovesicles and a spongiotic histological pattern, whereas LS presents with flat lichenoid papules without spongiosis, as observed in our patient. The considerable clinicopathological overlap has led some authors to regard these conditions as part of a single continuum described by the term blaschkolinear acquired inflammatory skin eruption (BLAISE).

Conclusion: Although rare in adults, LS should be considered in the differential diagnosis of any acute, acquired, blaschkolinear eruption in this age group. It generally resolves spontaneously, and treatment is usually unnecessary except for the symptomatic management of pruritus.