Lichen planus is a chronic inflammatory disease of unknown origin, which most commonly affects individuals between 30–60 years of age and is characterized by different types of lesions involving the skin and mucosa.

Epidemiology

Etiology

Associated with hepatitis C infections

Pathophysiology

Clinical features

Cutaneous lichen planus

5 “Ps”: pruritic, purple/pink, polygonal, papules & plaques
Lesions
- Purple, well-demarcated papules or plaques
- Planar (flat-topped)
- Polygonal, irregular borders
- Pruritic, often severe
- Wickham striae: white, reticular lines on the surface of mucosal lesions
Distribution pattern
- Affects the extremities, especially the ankles and flexor wrists, as well as the trunk
- Bilateral, symmetrical distribution