lichen planus

Etiology

• idiopathic or chronic trauma
• pharmaceutical agents may induce lichen planus-like eruption (see lichenoid eruption)
• color film developers may induce lichen planus-like eruption (see lichenoid eruption)
• chronic graft vs. host reaction
• dermatomyositis
• cutaneous manifestation of malignant lymphoma
• frequently associated with hepatitis C

Epidemiology

• 30-60 years of age; may occur in older women]
• females > males
• hypertrophic lichen planus more common in blacks

Pathology

• T-cell mediated, chronic inflammatory mucocutaneous condition

Genetics

• overexpression of kallikrein-8

Clinical manifestations

• flat-topped, violaceous, shiny pruritic papules on the skin
  • small polygonal violaceous papules
  • most commonly presents on forearm, wrist & ankles
• 40-60% of individuals have oropharyngeal involvement
  • mucosal involvement frequently includes buccal mucosa, gingiva, tongue, lips, esophagus
    • commonly affects both oral & vaginal mucosa, but it may present as only a genital lesion (vulvovaginal)
  • white papules or lace-like striae (Wickham striae)
  • reticular white plaques of the oral mucosa
  • hyperkeratosis or painful erosions or ulceration
  • dry mouth
• mucous membrane: may be painful, especially when ulcerated
• eruption may be acute; duration of lesions months to years
• skin: asymptomatic to intensely pruritic
  • occurs in areas of trauma such as scratching (Koebner phenomenon)
• papules 1-10 mm, sharply defined, rarely bullae
• hypertrophic plaque, often with post-inflammatory hyperpigmentation
• violaceous papule with white-line; white reticulated network on buccal mucosa (Wickham's striae)
• post-inflammatory hyperpigmentation common in dark-skinned individuals
• grouped, linear, annular or scattered discrete lesions
• distribution:
  • flexor aspect of forearm & wrists
  • inner aspects of elbows, knees, pretibial region, ankles
  • lower back, lumbar region
  • eyelids
  • scalp
  • nails (thickening of nail plate)
  • genitalia
    • vaginal involvement in 70% of women with erosive lichen planus
    • vulvar scarring
    • glassy erythematous erosions with white striae along the margins involving the labia minora & vestibule
    • vaginal scarring with erosions & striae extending into the vagina
• distribution on sun-exposed sites suggests
  • lichen planus actinicus
  • lichenoid drug eruption
• types of lesions
  • reticular
  • plaque-type
  • atrophic
  • ulcerative
  • bullous
• papular, annular or ulcerative lesions on glans penis, scrotum, labia, vagina
• atrophic scalp with scarring alopecia
• destruction of nail fold & nail bed, especially in large toe

* images

Laboratory

• skin biopsy

Complications

• malignant transformation of oral lesions (SCC)

Differential diagnosis

• lichenoid drug eruption
• lichen sclerosus (vaginal involvement uncommon)
• lichen simplex chronicus (genetically atopic individuals)
• vulvar intraepithelial neoplasia (typically visible raised lesion with atypical vascular patterns, but may be flat, white, red, brown, or black)
• pityriasis rosea
  • pityriasis rosea often presents with herald patch
  • scratching the lichen planus can result in a linear-appearing rash, mimicking appearance of pityriasis rosea
  • lichen planus is more purple in color than pityriasis rosea
    • tends to erupt on the lower back
  • pityriasis rosea tends to erupt on the upper & mid-back
  • rash on wrist unusual for pityriasis rosea
• psoriasis
  • thick, well-demarcated erythematous plaques with overlying silvery scale
  • nail psoriasis presents with nail pitting, onycholysis
• secondary syphilis
  • more brownish red in color compared vs purple papules of lichen planus
  • involves trunk & extremities, often including palms & soles
  • generalized lymphadenopathy
• geographic tongue
  • appearance of denuded red patches migrating across the surface of the tongue
  • map-like erythematous patches with white hyperkeratotic rims on dorsal surface of tongue
• oral leukoplakia
  • patches or plaques of the oral mucosa, associated with tobacco or chronic trauma
• oral hairy leukoplakia
  • adherent white plaques, associated with EBV, HIV1 infection

Management

• glucocorticoids
  • potent topical glucocorticoid (clobetasol)
    • may decrease pruritus & size of lesions
    • may not be curative
    • for local disease (including mucosa), topical treatment is appropriate
  • intralesional triamcinolone (3 mg/mL)
  • oral prednisone
    • begin 70 mg PO QD or 1 mg/kg/day
    • taper by 5 mg QD
    • also consider pulse therapy (GRS9)
• retinoids
  • topical retinoic acid
  • acitretin (Soriatane) 1 mg/kg PO QD
  • etretinate (Tegison) 1 mg/kg PO QD
• sulfasalazine
• PUVA phototherapy
• calcineurin inhibitors
  • topical tacrolimus
  • topical pimecrolimus
  • cyclosporine 5 mg/kg/day (resistant cases)
• hydroxychloroquine
• thalidomide 150-200 mg QHS
• systemic therapy & phototherapy should be reserved for severe or recalcitrant cutaneous disease
  • systemic therapy for persistent oral disease

More general terms

• lichenoid dermatitis
• chronic skin disease

More specific terms

• familial lichen planus
• follicular lichen planus; lichen planopilaris; Graham Little-Piccardi-Lassueur syndrome
• hypertrophic lichen planus
• lichen planus actinicus
• ulcerative lichen planus
• vesicular lichen planus

Additional terms

• lichen sclerosus
• lichenification
• lichenoid eruption

Patient information

lichen planus patient information