Lichen Planus

Lichen Planus is a condition that affects the skin and mucous membranes, causing an itchy rash and sometimes painful sores. It mainly involves the skin, mouth, and sometimes the genital area. The rash appears as flat-topped, shiny, purple bumps that can be very uncomfortable. In the mouth, it causes white, lacy patches or painful ulcers that can make eating and speaking difficult. This condition is caused by the immune system mistakenly attacking the skin and mucous membranes. It is not contagious and can last for months to years, sometimes coming and going. The main health impact is discomfort and potential scarring in affected areas.

Lichen Planus is a chronic inflammatory disorder characterized by a T-cell mediated autoimmune reaction against basal keratinocytes in the skin and mucous membranes. The pathogenesis involves CD8+ cytotoxic T cells targeting basal epidermal cells, leading to apoptosis and a characteristic band-like lymphocytic infiltrate at the dermoepidermal junction. It commonly affects middle-aged adults and presents with pruritic, polygonal, purple papules on the skin and reticular white plaques or erosions in the oral mucosa. The disease can also involve nails and genital mucosa, causing significant morbidity. Histologically, it shows hypergranulosis, sawtooth acanthosis, and Civatte bodies (apoptotic keratinocytes). The exact trigger is unknown but may be related to infections, medications, or stress. It is important due to its chronic course and potential for malignant transformation in oral lesions.