View source for Lichen planus

==Background==
*Uncommon disorder of unknown cause, likely T-cell mediated autoimmunity against basal kertinocytes<ref>Le Cleach L, Chosidow O. Clinical practice. Lichen planus. N Engl J Med. 2012;366(8):723-732. PMID 22356325</ref>
*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”
**[[Pruritus|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 DDX}}

==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

==See Also==

==External Links==

==References==
*Goldstein, BG, Goldstein, AO, Mostow, E. Lichen planus. In: UpToDate, Dellavalle, RP, Callen, J (Ed), UpToDate, Waltham, MA, 2017.
[[Category:Dermatology]]