Widespread Lichen Planus

Description

Purplish-red, flat-topped papules coalesce into broad plaques along the lateral trunk and the upper limb, extending distally toward the wrist in a distribution typical of cutaneous lichen planus. Fine, lacy white surface lines consistent with Wickham striae are suggested over the more violaceous areas, while the surrounding skin remains comparatively unremarkable against the neutral background. Proximally, the eruption occupies the upper arm and flank; distally it tracks along the forearm toward the flexor aspect, where lichen planus often declares itself. Scale is minimal, and the color shift from erythematous to violaceous supports an interface dermatitis rather than a urticarial process. Cutaneous lichen planus matters because its morphology and topography help you separate it from mimics such as pityriasis rosea, psoriasis, drug-induced lichenoid eruption, and allergic contact dermatitis. The classic pruritic, polygonal, violaceous papules and potential Koebner phenomenon (new lesions at sites of friction or minor trauma) explain why lesions may appear linear or more intense along exposed or irritated skin. When widespread disease is present, clinicians often screen for mucosal involvement (oral reticular plaques, erosive lesions) and review medications and systemic associations, including hepatitis C risk in appropriate populations, since management and follow-up can change. Dermatology and pathology educators can use this asset to teach pattern recognition of inflammatory papulosquamous disease, emphasizing Wickham striae, flexor-predominant distribution, and the clinical logic behind biopsy site selection. Medical publishers will find it suitable for chapters on interface dermatitis, immune-mediated rashes, and differential diagnosis tables contrasting lichen planus with psoriasis and lichenoid drug reactions. In clinical settings, it supports patient counseling materials on chronicity, post-inflammatory hyperpigmentation, and expected treatment response to topical corticosteroids or calcineurin inhibitors. Anatomical accuracy verified by SciePro's Medical Advisory Board.