What is the hallmark manifestation of lichen planus?

Lichen planus is most commonly characterized by its involvement of mucosal surfaces, such as the oral cavity and genital areas. The lesions in lichen planus are typically well-defined, polygonal, flat-topped papules that can appear on the skin but are particularly notable for their presentation in the mucosal membranes. Oral lichen planus can lead to a white, reticular appearance, or may present as erosive lesions that can be painful, contributing to discomfort with eating or hygiene practices.

The significance of mucosal involvement is paramount in diagnosing lichen planus, as it distinguishes the condition from other dermatoses that may present in similar ways but do not typically affect mucosal tissues. Understanding this manifestation is critical, as the management and implications of lesions in these sensitive areas may differ notably from other types of cutaneous disorders.

In contrast, while acne vulgaris symptoms, psoriatic lesions on elbows, or blistering and flaking skin may be seen in other dermatological conditions, they do not represent the defining characteristics of lichen planus. The focus on mucosal surface involvement is a key distinguishing feature that aids in accurate diagnosis and subsequent management of the disease.