Ichthyosis Ichthyosis linearis circumflexa 2025-04-17T16:14:38Z A type of ichthyosis characterized by migratory, annular and polycyclic erythematous patches with double-edged scales at the periphery of the lesions. Double-edged scaling Serpiginous scaling The erythematous patch (flat area of redness 1 cm or more in width) that is ring-shaped (annular) or serpiginous (with multiple ring-shaped lesions (polycyclic). The lesions are bordered by two distinct rings of scale at their outer edges (double-edged). The distribution of the lesions changes with time (migratory). Ichthyosis linearis circumflexa (ILC) may rarely be observed as an isolated lesion, but is a characteristic manifestation of Netherton syndrome. Lesions are often described as serpiginous scaling or double-edged scaling.