Lichen planus

Introduction

Lichen Planus is a chronic, pruritic, papular skin disease.  It has three cardinal features which include:

  1. Skin lesions
  2. Mucosal lesions
  3. Histopathologic features of band-like infiltration of lymphocytes and melanophages in the upper dermis.

Some of the drugs known to cause lichen planus (LP) are

  • Chloroquine
  • Quinacrine
  • Quinidine
  • Gold
  • Streptomycin
  • Tetracycline
  • NSAIDS
  • Phenothiazines
  • Hydrochlorothiazide

Symptoms and clinical features of lichen planus

  1. Lichen Planus has been found in children, young and middle-aged adults
  2. The skin lesions are flat-topped polygonal papules with a characteristic colour
    • Violaceous in fair skinned people but slate-grey on black skin
  3. Itching is mild-to-severe
  4. Like psoriasis, lesions often occur on sites of trauma and scratch marks (Koebner’s or isomorphic phenomenon)
  5. Wickham’s striae are fine white streaks present on the tops of papules
  6. The lesions are distributed mainly on:
    • Flexor surfaces of the wrist
    • Lumbar area
    • The penis, tongue, buccal and vaginal mucous membranes
  7. On the buccal mucous membrane it may present as white reticulate pattern or plaque which may after several years transgress into squamous cell carcinoma
  8. The nails are also affected with:
    • Pitting, roughening and splitting
    • Thickening (pachyonychia) (trachyonychia)
    • Encroachment of the nail fold on the nail plate (pterygium ungium)
  9. Total destruction of all 20 nails may precede, accompany, or follow the onset of skin lesions
  10. The hair follicles in the scalp may also be affected (lichen planopilaris) with post inflammatory scarring alopecia
  11. Hepatitis C infection is found with greater frequency in lichen planus than in controls
  12. Healing of the skin lesions leave post inflammatory hyperpigmentation

Differential diagnoses

Consider other papulosquamous disorders:

  • Psoriasis
  • Pityriasis rosea
  • Lupus erythematosus
  • Secondary syphilis
  • Lichen striatus
  • Parapsoriasis
  • Pityriasis rubra pilaris

Nummular eczema Oral lesions:- Erosive lesions may mimic
Aphthous stomatitis and herpes simplex

  • White plaques may be confused with Pre malignant leukoplakia

White sponge naevus

Complications of lichen planus

  • 20-nail dystrophy
  • Rarely, squamous cell carcinoma of oral and hypertrophic lichen planus

Investigations

  • Histopathology
  • Hepatitis C antigen

Treatment for lichen planus

Treatment objectives

  1. Relieve itching
  2. Clear lesions
  3. Suppress inflammation

Drug treatment

Topical corticosteroids:

Beclomethasone dipropionate 0.1% cream

  • Apply 1-2 times daily.
  • Not licensed for use in children under one year

Bethamethasone valarate 0.1% cream and ointment

  • Apply 1-2 times daily
  • For isolated or hyperkeratotic lesions apply corticosteroids under occlusion or use intralesional triamcinolone

Scalp lesions:
Topical corticosteroids
Clobetasol propionate 0.05% lotion

  • Apply thinly 1-2 times daily for up to 4 weeks

Mouth lesions:
Triamcinolone acetonide 0.1% in adhesive base

  • Apply a thin layer 2 – 4 times daily for a maximum of 5 days; do not rub in

Or:

Tretinoin 0.025% cream

  • Adult and child: apply thinly 1-2 times daily

Systemic corticosteroids

Prednisolone

  • Adult: 20-40 mg orally daily for several weeks with reduction of dosage or switch to alternate-day therapy as soon as improvement is seen
  • Child: not recommended for children for this indication

Or:

Triamcinolone acetonide 40 mg.
intramuscularly once or twice (at a 6-week interval)

Or:

Ciclosporin

  • Adult and child over 16 years: 2.5 mg/kg daily in two divided doses. If good results not achieved within two weeks increase rapidly to maximum 5 mg/kg daily

Notable adverse drug reactions

Prevention of lichen planus

  • Avoid precipitating drugs