dermatology

1. Lichen Planus

2. Definition
• “Dermatosis of unknown origin characterised by
typical violaceous papular eruption on
characteristic sites and white mucosal lesions.”
• (dermatosis means non-inflammatory lesion which
involves integumentary system)

4. Pathogenesis
• Lichen planus is a T cell-mediated autoimmune
disease, in which inflammatory cells attack an
unknown protein within skin and mucosal
keratinocytes.
• HLA-3 , HLA-5

5. Etiology
• Associated with other immune conditions e.g.
ulcerative colitis , alopecia areata , vitiligo etc .
• Genetic predisposition 1-2%
• Associated with hepatitis C virus infection.
• Koebner`s phenomena
• Drugs e.g. gold , quinine , arsenic , isoniazid ,
streptomycin , photocolor developer , dental
amalgam
• Complication of bone marrow transplant

6. Involves:
• Skin
• Mucous membrane
• Legs
• Scalp
• Genitalia

7. Patient presents with :
• Pin-point papules/ polygonal plaques
• Grouped /discrete
• Well-marked itching
• Initially , they develop on flexures and later
generalised eruption occurs .

8. 5Ps
Plane-
topped
purple
pruritic
polygon
al
papules

9. Common sites :
• Wrists and forearm
• Lumbar region
• Lower legs and ankles

10. Chronic lesions
Palms and soles :
• yellowish
• hyperkeratotic papules
Nail changes
• Thinning
• Longitudnal lines
• Pterygium(scar)

11. Wickham`s straie

12. Mucosal lesion
Network of white streaks characteristic

13. Colour changes
Early lesion Late lesion

14. Legs(develops into chronic hypertrophic)

15. Palms, soles

16. Lichen-planopilaris

17. Nails

18. Prognosis
• Acute attack clears in 6-9 months .
• Ordinary type 6-18 months .
• Hypertrophic types takes several years .

19. Diagnosis
• Clinically
• Biposy may be taken to confirm and look for
complication i.e SCC
• Patch test : in case of oral lesions to check for
mercury allergy .

20. Treatment
• Acute : topical steroids , antihistamine .
• Hypertrophic : intralesional steroid , oral
antihistamine .
• Severe local/systemic : oral prednisolone

21. Other options for widespread disease :
• Narrow-band or broadband UV-B therapy
• Psoralen with UV-A (PUVA) therapy
• Azathioprine
• cyclosporin