Lichen Planus: Cutaneous and Mucosal Variants

Overview / Definition Lichen Planus is an inflammatory disorder that primarily affects the skin and mucous membranes. It is characterized by polygonal, flat-topped, purple papules that can be itchy and are often found on flexural surfaces, oral cavity, and genital regions. The condition is considered an autoimmune disease and can have systemic implications in some patients. Epidemiology Lichen Planus has a prevalence of approximately 0.1% to 4% in the general population, with variations based on geography and ethnicity. The disease can occur at any age but is most commonly seen in adults aged 30 to 60 years. Both sexes are affected equally. Age of onset: 30-60 years Gender: Equal prevalence in males and females Geographic variations: Higher prevalence in certain populations (e.g., Hispanic and Black individuals) Pathophysiology / Mechanism The exact etiology of Lichen Planus is unknown, but it is thought to be related to a cell-mediated immune response. The disease is characterized by a band-like infiltrate of lymphocytes at the dermal-epidermal junction, leading to damage of the basal cell layer. Various triggering factors have been identified, including: Medications: Nonsteroidal anti-inflammatory drugs (NSAIDs), beta-blockers, and certain antihypertensives Infections: Hepatitis C virus has been notably associated Stress: Psychological stress can exacerbate symptoms Clinical Presentation Lichen Planus can present in various forms, including: Cutaneous Lichen Planus: Characterized by the classic purple papules, often accompanied by Wickham's striae (white lacy lines) and pruritus. Mucosal Lichen Planus: Presents as white, reticular lesions in the oral cavity, often asymptomatic but can cause discomfort. Annular Lichen Planus: Presents as annular plaques that may resemble tinea corporis. Hypertrophic Lichen Planus: Thickened plaques, often on the lower extremities, that can be very itchy. Atrophic Lichen Planus: Thinning of the skin, often seen in older patients. Di