Lichen Planus

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)

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

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

Involves:•Skin

•Mucous membrane

•Legs

•Scalp

•Genitalia

Patient presents with :•Pin-point papules/ polygonal plaques•Grouped /discrete•Well-marked itching

• Initially , they develop on flexures and later generalised eruption occurs .

5PsPlane-topped

purple

pruriticpolygonal

papules

Common sites :

•Wrists and forearm

•Lumbar region

•Lower legs and ankles

Chronic lesions Palms and soles :

• yellowish

• hyperkeratotic papules

Nail changes

• Thinning

• Longitudnal lines

• Pterygium(scar)

Wickham`s straie

Mucosal lesion

Network of white streaks characteristic

Colour changesEarly lesion Late lesion

Legs(develops into chronic hypertrophic)

Palms, soles

Lichen-planopilaris

Nails

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

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 .

Treatment •Acute : topical steroids , antihistamine .

•Hypertrophic : intralesional steroid , oral antihistamine .

•Severe local/systemic : oral prednisolone

Other options for widespread disease :•Narrow-band or broadband UV-B therapy 

•Psoralen with UV-A (PUVA) therapy

•Azathioprine

•cyclosporin

Thank you !