What is the clinical characteristic feature of Lichen Planus?

Lichen Planus is an inflammatory condition that affects the skin and mucous membranes, and one of its hallmark clinical characteristics is the presence of a dense band of T-lymphocytes located just beneath the epithelium. This infiltration is indicative of the immune response involved in the pathophysiology of the condition. The presence of these immune cells is a crucial part of the diagnosis, as it reflects the underlying immunological mechanisms that drive the lesions associated with Lichen Planus.

In contrast, while white patches on the tongue can be a manifestation of the disease, they are not considered a defining characteristic; similar presentations can occur in other oral conditions. The occurrence of vesicles is also not typical for Lichen Planus; the condition usually presents as flat, polygonal, purplish papules rather than vesicular lesions. Lastly, ulceration of the gums may occur in Lichen Planus but is not a primary feature, as the condition is characterized more by the appearance of reticular or papular lesions rather than overt ulceration. Therefore, the presence of a dense subepithelial T-lymphocytic band is the most clinically characteristic feature of Lichen Planus.