Lichen planus

Background

• Uncommon disorder of unknown cause, likely T-cell mediated autoimmunity against basal kertinocytes
• Most common in patients aged 30 to 60 years
• HCV association is controversial
• Drug exposure can resemble idiopathic lichen planus

Affected areas

• Skin (cutaneous lichen planus)
• Oral cavity (oral lichen planus)
• Genitalia (penile or vulvar lichen planus)
• Scalp (lichen planopilaris)
• Nails
• Esophagus

Clinical Features

Cutaneous Lichen Planus

Predominantly on ankles and volar surface of wrists

• Four “P’s”
  • Pruritic
  • Purple
  • Polygonal
  • Papules or plaques
• Wickham’s striae: Fine white lines visible on surface of papules or plaques
• Koebner reaction: Lesions develop in areas of trauma (e.g., scratching)

Cutaneous variants

Hypertrophic lichen planus

• Intensely pruritic, flat-topped plaques
• Common sites are extensor surfaces of lower extremities

Atrophic lichen planus

• Violaceous, round or oval, atrophic plaques
• Common sites are legs
• Often resolution of annular or hypertrophic lesions

Annular lichen planus

• Violaceous plaques with central clearing
• Common sites are penis, scrotum, and intertriginous areas

Bullous lichen planus

• Vesicles or bullae within existing lesions
• Common sites are legs

Actinic lichen planus (lichen planus tropicus)

• Photodistributed eruption of hyperpigmented macules, annular papules, or plaques
• Most common in Africa, Middle East, and India

Lichen planus pigmentosus

• Gray-brown or dark brown macules or patches
• Sun-exposed or flexural areas
• Pruritus minimal or absent

Inverse lichen planus

• Erythematous to violaceous papules and plaques
• Intertriginous sites (e.g., axillae, inguinal creases, inframammary area, limb flexures)
• Hyperpigmentation is common
• Scales and erosions may be present

Overlap syndromes

• Lichen planus pemphigoides
• Lichen planus-lupus erythematosus overlap syndrome

Other forms of lichen planus

• Nail lichen planus
  • Varies from minor atrophy to total nail loss
• Lichen planopilaris (follicular lichen planus)
  • Keratotic papules that may coalesce into plaques
  • Classic site is the scalp
  • May be in other body sites (e.g., Graham-Little-Piccardi-Lasseur syndrome)
  • Untreated, can result in scarring and permanent alopecia
• Oral lichen planus
  • Painful, frequent loss of appetite
  • May lead to secondary candida infection
• Genital lichen planus
  • Involves glans of penis or epithelium of vulva, vestibule, vagina, and mouth
  • Often resistant to treatment
• Esophageal lichen planus
  • Associated dysphagia or odynophagia
  • Concomitant oral, genital, or cutaneous lichen planus
• Otic lichen planus
  • Erythema, induration, and stenosis of external auditory canal
  • Thickening of TM
  • Otorrhea
  • Hearing loss

Differential diagnosis

The differential diagnosis for lichen planus includes:

• Chronic graft-versus-host disease
• Psoriasis
• Atopic dermatitis
• Lichen simplex chronicus
• Subacute cutaneous or discoid lupus erythematosus
• Pityriasis rosea
• Secondary syphilis
• Prurigo nodularis
• Paraneoplastic pemphigus/paraneoplastic autoimmune multiorgan syndrome (PAMS)
• Oral leukoplakia
• Oral candidiasis
• Pemphigus vulgaris, benign mucous membrane pemphigoid
• Lichenoid drug eruption
  • Antimicrobials: aminosalicylate sodium, ethambutol, griseofulvin, ketoconazole, streptomycin, tetracycline, trovafloxacin, isoniazid
  • Antihistamines: ranitidine, roxatidine
  • Antihypertensives/antiarrhythmics: ACE-inhibitors, doxazosin, beta blockers, methyldopa, prazosin, nifedipine, quinidine
  • Antimalarial drugs: chloroquine, hydroxychloroquine, quinine
  • Antidepressants/anxiolytics/antipsychotics/AEDs: amitriptyline, carbamazepine, chlorpromazine, levomepromazine, methoprazine, imipramine, lorazepam, phenytoin
  • Diuretics: thiazide diuretics, furosemide, spironolactone
  • Antidiabetics: sulfonylureas
  • Metals: gold salts, arsenic, bismuth, mercury, palladium, lithium
  • NSAIDs
  • Proton pump inhibitors: omeprazole, lansoprazole, pantoprazole
  • Lipid lowering drugs: pravastatin, simvastatin, gemfibrozil
  • TNF-alpha antagonists: infliximab, adalimumab, etanercept, lenercept
  • Varia: allopurinol, bleomycin, cinnarizine, cyanamide, dapsone, hydroxyurea, hepatitis B-vaccine, imatinib, immunoglobulins, interferon alfa, l-thyroxin, levamisole, mesalamine, methycran, penicillamine, procainamide, pyrimethamine, pyrithioxine, quinacrine, sildenafil, sulfasalazine, terbinafine, trihexyphenidyl, ursodeoxycholic acid

Plaques

• Psoriasis
• Bowen disease
• Discoid lupus erythematosus
• Drug eruption
• Erythema annulare centrifugum
• Lichen planus
• Lichen simplex chronicus
• Nummular dermatitis (nummular eczema)
• Parapsoriasis
• Pityriasis rosea
• Seborrheic dermatitis

Diagnosis

• Clinical diagnosis
• Workup outside of ED may include:
  • Punch biopsy or shave biopsy
  • Immunofluorescence studies if bullous lesions present
  • Routine HCV testing controversial

Management

Cutaneous

• Self-limiting disease, usually resolves within 8-12 months
• First-line
  • Topical corticosteroid
    • High potency (e.g., trunk, extremities)
      • 0.05% betamethasone dipropionate cream/ointment BID
      • 0.05% diflorasone diacetate cream/ointment BID
    • Mid- or low-potency (e.g., intertriginous areas, facial skin)
  • Intralesional corticosteroids (hypertrophic lichen planus)
    • 2.5 to 10 mg/ml triamcinolone acetonide q4-6 weeks
• Second-line therapy
  • For generalized disease or local corticosteroid-refractory disease
    • Oral glucocorticoids
      • Optimal dose/duration unknown
      • 30 to 60 mg qd 4-6 weeks followed by 4-6 week taper
    • Phototherapy (e.g, Ultraviolet B, psoralen plus Ultraviolet A)
    • Oral acitretin

Genital

• Topical corticosteroids or topical calcineurin inhibitors

Lichen planopilaris

• Topical corticosteroids or intralesional corticosteroids

Oral

• Topical corticosteroids

Nail

• Systemic or intralesional corticosteroids

Disposition

• Outpatient treatment

Prognosis

Cutaneous lichen planus

• Remits within 1 to 2 years

Oral, genital, scalp, and nail lichen planus

• More persistent and resistant to therapy
• Squamous cell carcinoma risk is unclear (highest risk with erythematous or erosive oral and genital lichen planus)

Monitor for medication adverse effects

References

• Goldstein, BG, Goldstein, AO, Mostow, E. Lichen planus. In: UpToDate, Dellavalle, RP, Callen, J (Ed), UpToDate, Waltham, MA, 2017.