Lichen Planus (LP)
Lichen Planus is a chronic inflammatory, autoimmune condition affecting the skin, nails, hair, and mucous membranes. It is clinically characterized by the classic “6 Ps.”
The “6 Ps” of Lichen Planus
- Planar (flat-topped)
- Purple (violaceous)
- Polygonal
- Pruritic
- Papules
- Plaques
Key Clinical & Histological Features
| Feature | Description |
|---|---|
| Wickham Striae | Fine white lace-like lines on the surface of lesions. |
| Oral Involvement | Often presents as reticular white patches on the buccal mucosa. |
| Histopathology | Sawtooth rete ridges, hyperkeratosis, and lichenoid interface dermatitis. |
High-Yield Exam Pearl:
- Associated Condition: Lichen Planus is strongly associated with Hepatitis C infection. Always consider testing if a patient presents with widespread or recalcitrant disease.
- Koebner Phenomenon: LP lesions often develop at sites of physical trauma (e.g., scratches), similar to Psoriasis and Vitiligo.