Lichen planus

Background

• Uncommon disorder of unknown cause
• Estimated < 1% occurrence rate, most frequently 30 to 60 years of age
• Proposed immune-mediated mechanism, T cells (primarily CD8+) activated against basal keratinocytes
  • 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 anterior lower legs
• Occasionally develops cutaneous squamous cell carcinoma

Annular lichen planus

• Violaceous plaques with central clearing (central atrophy may occur)
• 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 Middle East, India, and east Africa

Lichen planus pigmentosus

• Gray-brown or dark brown macules or patches
• Sun-exposed or flexural areas
• Pruritis 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

Atrophic lichen planus

• Violaceous, round or oval, atrophic plaques
• Common sites are legs

Lichen planopilaris (follicular lichen planus)

• Classic site is the scalp
• May be in other body sites (e.g., Graham-Little-Piccardi-Lasseur syndrome)

Overlap syndromes

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

Other forms of lichen planus

• Nail lichen planus
  File:Lehman, 2009 Fig11.tiff

  Lichen planus involving the nails
  • Varies from minor atrophy to total nail loss
• Lichen planopilaris
  • Occurs on the scalp causing hair loss with keratotic follicular papules
  • Untreated, can result in scarring and permanent alopecia
• Oral lichen planus
  File:Lichen Planus Fig7.tiff

  Lichen planus on the lips and the lateral border of the tongue
  • 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:

• Lichenoid drug eruption
  • Antimicrobial substances
    • Aminosalicylate sodium, ethambutol, griseofulvin, ketoconazole, streptomycin, tetracycline, trovafloxacin, isoniazid
  • Antihistamines
    • Ranitidine, roxatidine
  • Antihypertensives/antiarrhythmics
    • ACE-inhibitors (captopril, enalapril), doxazosin, beta blockers (propranolol, labetalol, sotalol), methyldopa, prazosin, nifedipine, quinidine
  • Antimalarial drugs
    • Chloroquine, hydroxychloroquine, quinine
  • Antidepressives/antianxiety drugs/antipsychotics/anticonvulsants
    • Amitriptyline, carbamazepine, chlorpromazine, levomepromazine, methopromazine, imipramine, lorazepam, phenytoin
  • Diuretics
    • Thiazide diuretics (chlorothiazide and hydrochlorothiazide), furosemide, spironolactone
  • Antidiabetics
    • Sulfonylureas (chlorpropamide, glimepiride, tolazamide, tolbutamide, glyburide)
  • Metals
    • Gold salts, arsenic, bismuth, mercury, palladium, lithium
  • Non-steroidal-antiinflammatory drugs (NSAIDs)
    • Acetylsalicylic acid, benoxaprofen, diflunisal, fenclofenac, flurbiprofen, ibuprofen, indomethacin, naproxen, sulindac
  • 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
• Chronic graft-versus-host disease
• Psoriasis
• Atopic dermatitis
• Lichen simplex chronicus
• Subacute cutaneous lupus erythematosus
• 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

Diagnosis

• Often clinical diagnosis

Questions to ask

• Current medications
• Pruritus
• Oral or genital erosions or pain
• Dysphagia or odynophagia
• Risk factors for HCV

Physical exam

• Expose and examine all cutaneous surfaces

Biopsy (e.g., punch biopsy, shave biopsy)

• Immunofluorescence studies if bullous lesions present

Dermoscopy

• Wickham’s striae

HCV testing

• Routine testing controversial

Histopathology

• Pathologic findings seen in lichen planus
  • Hyperkeratosis without parakeratosis
  • Apoptotic keratinocytes in lower epidermis (Civatte bodies) and papillary dermis (eosinophilic colloid bodies)
  • Wedge-shaped hypergranulosis
  • Bandlike infiltrate of lymphocytic and histiocytic cells
  • Linear or shaggy deposits of fibrin and fibrinogen in basement membrane

Managment

Cutaneous lichen planus

• 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, Uultraviolet B, psoralen plus Ultraviolet A)
    • Oral acitretin

Genital lichen planus

• Topical corticosteroids or topical calcineurin inhibitors

Lichen planopilaris

• Topical corticosteroids or intralesional corticosteroids

Oral lichen planus

• Topical corticosteroids

Nail lichen planus

• Systemic or intralesional corticosteroids

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)