Adult-onset lichen striatus versus adult blaschkitis: a clinicopathological review of 40 cases of acquired blaschkolinear inflammatory dermatosis

Background: Since the first description of adult blaschkitis (AB), the existence of this entity has been a matter of great debate. Objectives: To compare clinicopathological features of lichen striatus (LS) and AB cases. Materials and Methods: We retrospectively reviewed the clinicopathological features of patients who clinically showed linear inflammatory dermatosis along Blaschko’s lines based on a skin biopsy registry. Results: Through a process of clinicopathological differential diagnosis, 27 cases of LS, three of AB, eight of linear lichen planus, and two of linear psoriasis were identified. Clinicopathological differences between LS and ABwere mostly insignificant except for age at onset and multiple site involvement. In these cases, females were affected more frequently than males. The mean age at onset was 31.6 years, and the most common involved site was the leg. The lesions lasted approximately 8.3 months with few relapses. The most common histopathological finding was perivascular infiltration followed by peri-appendageal infiltration. Conclusion: Distinction between LS and AB appears to be unnecessary given their overlapping features.