A Linear Affair: Blaschkoid Pattern in Lichen Planus Pigmentosus.

Lichen planus pigmentosus (LPP) is an acquired disorder of hyperpigmentation. Atypical presentations, such as linear or blaschkoid distribution, are exceedingly rare and may pose diagnostic challenges. We report a case of a 32-year-old male with pruritic, hyperpigmented, slate-gray to brown macules and patches distributed linearly along Blaschko's lines on the right upper back and upper limb. The diagnosis of LPP was corroborated by clinical appearance, dermoscopic examination, and histopathological analysis. Recognition of such unusual patterns is essential for accurate diagnosis and to differentiate from other linear pigmentary disorders.