Unravelling the spectrum: Isolated Blaschko linear psoriasis – A rare clinical entity

Blaschko linear psoriasis is a rare variant of psoriasis characterized by a distribution of psoriatic lesions along the lines of Blaschko. Isolated linear psoriasis, where there are no lesions elsewhere on the body, is exceedingly uncommon, with only a few cases documented in the literature. It often resembles other linear dermatoses like inflammatory linear verrucous epidermal nevus (ILVEN) or Koebner’s response of psoriasis over verrucous epidermal nevus. Here, we present a case of a 12-year-old male who presented with reddish, scaly lesions arranged in a linear fashion over the left upper limb since 3 years. The lesions clinically and histologically resembled psoriasis but had a distinct pattern of distribution, as they were unilateral and present along Blaschko’s lines. This case report emphasizes the significance of identifying the unique presentation of Blaschko linear psoriasis, understanding its diagnostic and treatment options, and differentiating it from ILVEN, despite their notable clinical similarities.