Lichen planus (LP) is an inflammatory autoimmune disorder affecting the skin, hair, nails, and mucous membranes. It is characterized by small, polygonal, flat-topped papules that are purple, shiny, and have fine white lines. LP has no clear cause but may be triggered by viral infections, autoimmune disorders, medications, or dental materials. Histology shows basal cell damage and a band-like lympho-histiocytic infiltrate. Treatment includes topical corticosteroids and antihistamines or systemic corticosteroids, dapsone, or retinoids depending on severity.

2. INTRODUCTION
• Lichen planus (LP) is an inflammatory T-cell mediated
autoimmune disorder affecting skin , hair nail & mucous
membrane
 Key descriptive features – 4P
Purple
Polygonal
Pruritus
Papule

3. EPIDEMIOLOGY
Age 30 – 60
1 – 4 % patients are children
Men and women are equally affected

4. AETIOLOGY & PATHOGENESIS
• It’s not well understood
• Risk factors are
Viral infections
Autoimmune disorders
Medications
Vaccinations
Restorative dental materials

5. • Cell mediated immunity plays a major role in
triggering clinical manifestations
• T-cell mediated autoimmune damage to basal
keratinocytes occur and that manifest as altered self
antigens on their surface

6. TARGET ANTIGENS
o Virus – HCV & other TTV
o Vaccines – HBV vaccine
o Contact allergens – Mercury , Copper & Gold
o Drugs – Antimicrobials , Antihypertensive ,
Antidepressants , Diuretics , NSAIDs etc

7. HISTOLOGY
• Biopsy shows irregular acanthosis of epidermis with
hypergranulosis & compact hyperkeratosis
• Basal cell damage , colloid bodies , pigment
incontinence & band like lympho histioctic infiltrate
obscuring the dermo-epidermal interface are other typical
charecteristics

9. CLINICAL FEATURES
• Primary lesion are small , polygonal , red or violet , flat
topped papules or plaques
• Surface is slightly shiny or transparent & a network of
fine white lines called Wickham’s striae or small grey
white puncta is also seen
• Papules may be widely dispersed or they may coalesce to
form large plaques
• Intense itching is fairly consistand feature

10. • Koebner’s phenomenon can be seen
• Common sites are flexor aspect of wrist & forearm ,
dorsum of hands , anterior aspect of lower limbs & neck
and pre sacral areas
• Face is usually spared
• Palmo-plantar involvement is unusual
• LP heals with hyperpigmentation

12. CLINICAL VARIETIES
CONFIGURATION
Annular
Linear
MORPHOLOGY
Hypertrophic
Atrophic
Vesiculo-bullous
Follicular

13. • Actinic – central hyperpigmentation and surrounding rim
of hypopigmentation
• Lichen planus pigmentosis – hyperpigmented dark
brown macules in sun exposed parts
SITE
Mucosal LP
Nail LP

14. Mucosal LP
Constitute 30 – 70 % of cases
With or without skin lesions
Seen in oral cavity , vagina , esophagus , conjunctiva ,
urethra , nose , anus & larynx
Reticular , plaque like , atrophic , papular , erosive ,
ulcerative and bullous form

15. Reticular lacy white pattern

18. Nail LP
Constitute 10 – 15 % of cases
Thinning , longitudinal ridging & distal splitting of
nail plate occurs
Forward growth of proximal nail fold (pterygium) with
adherence to proximal nail plate is classic sign

21. DIFFERENTIAL DIAGNOSIS
Cutaneous LP – Pityriasis rosea , Guttate psoriasis ,
Secondary syphilis & Lichenoid drug eruption
Mucosal LP – Candidiasis , Aphthous stomatitis
Pemphigus & Secondary syphilis
Nail LP – Psoriasis & Onychomycosis

22. TREATMENT
TOPICAL
Calamine lotion
Steroids (creams or intra lesional )
Retinoid
Tacrolimus
Topical lignocaine and beteamethasone mouth wash can
be used in oral LP

23. SYSTEMIC
Anti histamines ( to reduce pruritus )
Systemic corticosteroids
Dapsone
Systemic retinoid
Methotrexate
Phototherapy