Lichen planus is an immune-mediated skin condition characterized by flat-topped purple lesions. It can involve the skin, hair follicles, nails, and mucous membranes. The cause is unknown but may be related to genetic and environmental factors. Histopathology shows a T-cell mediated response against basal keratinocytes. Treatment involves avoiding triggers and using topical steroids or immunosuppressants. Oral lichen planus has a higher risk of transforming into skin cancer so prompt treatment is important.

4. Lichen planus/
'' Leichen‘’ means tree moss,
and ''planus'' means flat.

5. Immune-mediated dermatosis,
It involves skin, hair follicles, nails and/or mucosae (Oral,
Vulvovaginal)
There are several clinical types of lichen planus that share
similar features on histopathology.

6. Skin, Six P’s :
Planar (Flat-topped).
Purple (Post- hyperpigmentation).
Polygonal.
Pruritic (Rubbing rather Scratching).
Papules.
Plaques.
Mucosa : Wickham striae
Nail : Onychorrhexis, Onychoschezia, Dorsal Pterygium,
Trachyonychia, and Anonychia.
Characteristics

7. Skin, Six P’s :
Planar (Flat-topped).
Purple (Post-Inflammatory hyperpigmentation).
Polygonal.
Pruritic (Rubbing rather Scratching).
Papules.
Plaques.
Mucosa : Wickham striae, Macroscopic appearance shows
hypergranulosis
Nail : Onychorrhexis, Onychoschezia, Dorsal Pterygium,
Trachyonychia, and Anonychia.
Characteristics

8. ➢ Exact cause is Unknown.
➢ Genetic predisposition : MHC-1 (HLA-B7,8), MHC-2 (HLA DR1,10).
➢ Associations : Hepatitis C (Oral LP)
Aetiology
➢ Drugs : NSAIDs, ACEIs, Chloroquine, Mercury, Gold injections (in the past),
nickel sensitivity seen in oral LP.
and Ulcerative colitis, Alopecia areata, Vitiligo and dermatomyositis.

10. Pathogenesis
T-cell-mediated autoimmune injury to basal keratinocytes whose surface self-antigens have been altered
by Trauma or Infection (Altered MHC, HLA ).

11. Keratinocyte
Langerhan’s Cell

12. Histopathological changes

13. Histopathological changes

16. Histopathological changes
1.
2.
3.
4.
5.
6.

17. Classification

18. Cicatricial Alopecia
Three forms recognized ;
Classic,
Frontal fibrosing alopecia,
Graham little syndrome.

20. Classic (Follicular lichen planus)

23. Triad of : Cicatricial scalp alopecia , non-Cicatricial alopecia of the axilla,
eyebrows and groin, and Follicular lichen planus on the body.

26. Oral Lichen Planus
• Clinically: wickham striae.
• Associated highly with HCV.
• Resistant Non-healing oral lichen transforms into SCC!

28. Palmoplantar LP

29. Genital LP / Penile LP
• Site: glans penis.
• Clinically: classical papules in a ring around the glans. White streaks and
erosive lichen planus may occur but are less common.
• DDx/ Eczema, Psoriasis, Fixed drug eruption..

30. According to Shape and distribution

32. Acute generalized LP

33. • The Center is hyperpigmented or skin-coloured,
• Lesions resemble Granuloma Annulare.

34. Linear LP
following the lines of Blaschko.

35. LP Pigmentosus
Sun exposed areas and friction sites.

36. LP Pigmentosus

37. Hypertrophic LP

38. Atrophic LP

43. Treatment :
• Avoid sun exposure, sunscreen,
• Avoid Stress,
• Avoid offending drugs.

45. Topical Treatment :
✓ Topical Potent Steroid
✓ Topical Calcineurin Inhibitor

46. Systemic Treatment :
• Antihistaminics .
• Steroids e.g. prednisolone

47. Systemic Treatment : (cont.)
• PUVA: ( anti-mitotic, immunosuppressive)
• Narrow band UVB
• Cyclosporine (1-2.5 mg/kg/day)
• Anti-Malarial (hydroxychloroquine) especially in oral
lichen planus.