Examine individual changes

'{{Infobox medical condition | Name = Lichen planus | Image = Lichen Planus (2).JPG | Caption = Lichen planus affecting the shins. | Field = [[Dermatology]] | DiseasesDB = 7452 | ICD10 = {{ICD10|L|43||l|40}} | ICD9 = {{ICD9|697.0}} | ICDO = | OMIM = | MedlinePlus = 000867 | eMedicineSubj = derm | eMedicineTopic = 233 | eMedicine_mult = {{eMedicine2|derm|663}} | MeshID = D008010 | MeSH2 = D017676 }} '''Lichen planus''' ('''LP''') is a disease of the [[skin]] and/or [[mucous membrane]]s that resembles [[lichen]]. The cause is unknown, but it is thought to be the result of an [[autoimmune]] process with an unknown initial trigger. There is no cure, but many different medications and procedures have been used to control the symptoms. The term '''lichenoid reaction''' (or '''lichenoid lesion''') refers to a [[lesion]] of similar or identical [[histopathology|histopathologic]] and [[Clinical research|clinical]] appearance to lichen planus (i.e. an area which looks the same as lichen planus, both to the naked eye and under a [[microscope]]).<ref name=Greenberg2008>{{cite book|vauthors=Greenberg MS, Glick M, Ship JA |title=Burket's oral medicine|year=2008|publisher=BC Decker|location=Hamilton, Ont.|isbn=9781550093452|pages=89–97|url=https://books.google.com/books?id=Q2SP8cOZPvkC&pg=PA89 |edition=11th}}</ref><ref name=Lewis2012>{{cite book|vauthors=Lewis MA, Jordan RC |title=Oral medicine|year=2012|publisher=Manson Publishing|location=London|isbn=9781840761818|pages=66–72|url=https://books.google.com/books?id=_2uLqxLsg5IC&pg=PA70 |edition=2nd}}</ref> Sometimes dental materials or certain medications can cause a lichenoid reaction.<ref name=Greenberg2008 /> They can also occur in association with [[graft versus host disease]].<ref name=Greenberg2008 /><ref name=Barnes2009>{{cite book|last=Barnes L (editor)|title=Surgical pathology of the head and neck|year=2009|publisher=Informa healthcare|location=New York|isbn=9781420091632|edition=3rd}}</ref>{{rp|258}} ==Classification== Lichen planus (LP) is a chronic inflammatory disease of the skin, mucous membranes and nails.<ref name=":0">{{Cite journal|last=Di Lernia|first=Vito|date=2016-07-01|title=Targeting the IFN-γ/CXCL10 pathway in lichen planus|url=http://www.sciencedirect.com/science/article/pii/S0306987716300640|journal=Medical Hypotheses|volume=92|pages=60–61|doi=10.1016/j.mehy.2016.04.042}}</ref> Lichen planus lesions are so called because of their "lichen-like" appearance<ref name=TG2009>{{cite book|last=Limited|first=Therapeutic Guidelines|title=Therapeutic guidelines.|year=2009|publisher=Therapeutic Guidelines|location=North Melbourne, Vic.|isbn=978-0-9804764-3-9|pages=254–255, 302|edition=Version 3.}}</ref> and can be classified by the site they involve, or by their morphology. ===Site=== Lichen planus may be categorized as affecting [[mucous membrane|mucosal]] or [[skin|cutaneous]] surfaces. * ''Cutaneous'' forms are those affecting the skin, scalp, and nails.<ref name="Asch 2011">{{cite journal|last=Asch|first=S|author2=Goldenberg, G |title=Systemic treatment of cutaneous lichen planus: an update.|journal=Cutis; cutaneous medicine for the practitioner|date=March 2011|volume=87|issue=3|pages=129–34|pmid=21488570}}</ref><ref name="Sharma 2012">{{cite journal|last=Sharma|first=A|date=July 2012|title=Lichen planus: an update and review.|journal=Cutis; cutaneous medicine for the practitioner|volume=90|issue=1|pages=17–23|pmid=22908728|author2=Białynicki-Birula, R|author3=Schwartz, RA|author4=Janniger, CK}}</ref><ref name="Usatine 2011" /> * ''Mucosal'' forms are those affecting the lining of the [[gastrointestinal tract]] (mouth, pharynx, esophagus, stomach, anus), [[larynx]], and other mucosal surfaces including the genitals, [[peritoneum]], ears, nose, bladder and [[conjunctiva]] of the eyes.<ref name="Cheng 2012">{{cite journal|last=Cheng|first=S|author2=Kirtschig, G |author3=Cooper, S |author4=Thornhill, M |author5=Leonardi-Bee, J |author6= Murphy, R |title=Interventions for erosive lichen planus affecting mucosal sites.|journal=The Cochrane database of systematic reviews|date=Feb 15, 2012|volume=2|pages=CD008092|doi=10.1002/14651858.CD008092.pub2|pmid=22336835}}</ref><ref name=YAMADA2009 /><ref name="Bruch 2010">{{cite book|vauthors=Treister NS, Bruch JM |title=Clinical oral medicine and pathology|year=2010|publisher=Humana Press|location=New York|isbn=978-1-60327-519-4|pages=59–62}}</ref> ===Pattern=== Lichen planus lesions can occur in many different forms: {| class="wikitable" |- ! Lesion morphology!! Description<ref name=FITZPATRICK2003pp465-8>{{cite book |editor1-first=Irwin M. |editor1-last=Freedberg |title=Fitzpatrick's dermatology in general medicine |year=2003 |publisher=McGraw-Hill |location=New York, NY |isbn=0-07-138076-0 |pages=465–8 |edition=6th}}</ref><ref name=ANDREWS2006pp219-24>{{cite book |first1=William D. |last1=James |first2=Dirk M. |last2=Elston |first3=Timothy G. |last3=Berger |title=Andrews' Diseases of the skin : clinical dermatology |publisher=Saunders/ Elsevier |location=London |isbn=1-4377-0314-3 |edition=11th |pages=219–24}}</ref> |- | Annular || 'Ring-shaped' lesions that develop gradually from single small pigmented spots into circular groups of papules with clear, unaffected skin in the center. Annular lesions occur in approximately ten percent of lichen planus cases. The ring-like lesions may very slowly enlarge, co-join and morph into larger irregular (serpentine) bands, sometimes accompanied by lines (See Linear, below). |- | Linear || Papules are arranged in a line (the "Blaschko line").<ref name="GOROUHI2009">{{cite journal|last=Gorouhi|first=F|author2=Firooz A |author3=Khatami A |author4=Ladoyanni E |author5=Bouzari N |author6=Kamangar F |author7=Gill JK |title=Interventions for cutaneous lichen planus |journal=Cochrane Database of Systematic Reviews|year=2009|issue=4|doi=10.1002/14651858.CD008038|url=http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD008038/full}}</ref> This pattern may develop secondary to trauma ([[Koebner phenomenon|koebnerization]]) or, uncommonly, as a spontaneous, isolated eruption, usually on the extremities, and rarely on the face.<ref name=BOLOGNIA2008>{{cite book |editor1-last=Bolognia |editor1-first=Jean L. |title=Dermatology |year=2008 |publisher=Mosby/Elsevier |location=St. Louis |isbn=1-4160-2999-0 |edition=2nd |editor2-first=Joseph L. |editor2-last=Jorizzo |editor3-first=Ronald P. |editor3-last=Rapini}}</ref> |- | Hypertrophic || This pattern usually occurs on the extremities, especially the shins and the interphalangeal joints, and tends to be the most [[pruritic]] variant of lichen planus. Also known as "Lichen planus verrucosus". |- | Atrophic || This morphology is characterized by the presence of a few well-demarcated, white-bluish [[papule]]s or plaques with central superficial atrophy. This is a rare variant of lichen planus. |- | Bullous || This morphology is characterized by the development of vesicles and bullae with the skin lesions. This is a rare variant of lichen planus, and also known as "Vesiculobullous lichen planus". |- | Ulcerative || This morphology is characterized by chronic, painful bullae and ulceration of the feet, often with [[cicatricial alopecia|cicatricial]] sequelae evident. This is a rare variant of lichen planus. |- | Pigmented || This morphology is characterized by hyperpigmented, dark-brown [[macule]]s in sun-exposed areas and flexural folds. This is a rare variant of lichen planus. |} ===Overlap syndromes=== Occasionally, lichen planus is known to occur with other conditions. For example: * [[Lupus erythematosus]] overlap syndrome. Lesions of this syndrome share features of both lupus erythematosus and lichen planus. Lesions are usually large and hypopigmented, atrophic, and with a red-to-blue colour and minimal scaling. [[Telangectasia]] may be present.<ref name=ANDREWS2006pp219-24/><ref name=FITZPATRICK2003pp366_470-1>{{cite book |editor1-first=Irwin M. |editor1-last=Freedberg |title=Fitzpatrick's dermatology in general medicine |year=2003 |publisher=McGraw-Hill |location=New York, NY |isbn=0-07-138076-0 |pages=366, 470–1 |edition=6th}}</ref> * [[Lichen sclerosus]] overlap syndrome, sharing features of lichen planus and lichen sclerosus.<ref name=ANDREWS2006p220>{{cite book |first1=William D. |last1=James |first2=Dirk M. |last2=Elston |first3=Timothy G. |last3=Berger |title=Andrews' Diseases of the skin : clinical dermatology |publisher=Saunders/ Elsevier |location=London |isbn=1-4377-0314-3 |edition=11th |page=220}}</ref> ==Signs and symptoms== [[File:Lichen planus lip.jpg|thumb|right |Lichen planus affecting the lower lip.]] Although lichen planus can present with a variety of lesions, the most common presentation is as a well-defined area of purple-coloured, itchy, flat-topped papules with interspersed lacy white lines (Wickham's striae). This description is known as the characteristic "6 Ps" of lichen planus: planar (flat-topped), purple, polygonal, pruritic, papules, and plaques.<ref name="Usatine 2011" /> This rash, after regressing, is likely to leave an area of hyperpigmentation that slowly fades. That said, a variety of other lesions can also occur.<ref name=TG2009 /> ===Cutaneous lichen planus=== [[File:Lichen planus on leg.JPG|thumbnail|right|Cutaneous lichen planus on the shin.]] [[File:Lehman, 2009 Fig11.tiff|thumbnail|right|Lichen planus involving the nails.]] Variants of cutaneous lichen planus are distinguished based upon the appearance of the lesions and/or their distribution.<ref name=FITZPATRICK2003p466>{{cite book |editor1-first=Irwin M. |editor1-last=Freedberg |title=Fitzpatrick's dermatology in general medicine |year=2003 |publisher=McGraw-Hill |location=New York, NY |isbn=0-07-138076-0 |page=466 |edition=6th}}</ref> Lesions can affect the: * Extremities (face, dorsal hands, arms, and nape of neck).{{efn|Cutaneous lichen planus affecting the extremities is also known as "Lichen planus actinicus", "Actinic lichen niditus," "Lichen planus atrophicus annularis," "Lichen planus subtropicus," "Lichen planus tropicus," "Lichenoid melanodermatitis," and "Summertime actinic lichenoid eruption"}} This is more common in Middle Eastern countries in spring and summer, where sunlight appears to have a precipitating effect.<ref name=BOLOGNIA2008 /><ref name=FITZPATRICK2003p468>{{cite book |editor1-first=Irwin M. |editor1-last=Freedberg |title=Fitzpatrick's dermatology in general medicine |year=2003 |publisher=McGraw-Hill |location=New York, NY |isbn=0-07-138076-0 |page=468 |edition=6th}}</ref><ref name=ANDREWS2006p223>{{cite book |first1=William D. |last1=James |first2=Dirk M. |last2=Elston |first3=Timothy G. |last3=Berger |title=Andrews' Diseases of the skin : clinical dermatology |publisher=Saunders/ Elsevier |location=London |isbn=1-4377-0314-3 |edition=11th |page=223}}</ref> * Palms and soles * [[Intertriginous]] areas of the skin. This is also known as "Inverse lichen planus".<ref name=BOLOGNIA2008 /> * Nails<ref name="Gordon 2011">{{cite journal|last=Gordon|first=KA|author2=Vega, JM |author3=Tosti, A |title=Trachyonychia: a comprehensive review |journal=Indian journal of dermatology, venereology and leprology|date=Nov–Dec 2011|volume=77|issue=6|pages=640–5|doi=10.4103/0378-6323.86470|pmid=22016269}}</ref> characterized by irregular longitudinal grooving and ridging of the nail plate, thinning of the nail plate, pterygium formation, shedding of the nail plate with atrophy of the nail bed, subungual keratosis, longitudinal erthronychia (red streaks), and subungual hyperpigmentation.<ref name=ANDREWS2006p781>{{cite book |first1=William D. |last1=James |first2=Dirk M. |last2=Elston |first3=Timothy G. |last3=Berger |title=Andrews' Diseases of the skin : clinical dermatology |publisher=Saunders/ Elsevier |location=London |isbn=1-4377-0314-3 |edition=11th |page=781}}</ref> A [[Trachyonychia|sand-papered appearance]] is present in around 10% of individuals with nail lichen planus.<ref name="Gordon 2011" /> * Scalp. This is also known as lichen planopilaris, acuminatus, follicular lichen planus, and peripilaris,<ref name=FITZPATRICK2003p467>{{cite book |editor1-first=Irwin M. |editor1-last=Freedberg |title=Fitzpatrick's dermatology in general medicine |year=2003 |publisher=McGraw-Hill |location=New York, NY |isbn=0-07-138076-0 |page=467 |edition=6th}}</ref> characterised by violaceous, scaly, pruritic papules. Scalp lichen planus can cause [[scarring alopecia]] if it is untreated.<ref name="Usatine 2011">{{cite journal|last=Usatine|first=RP|author2=Tinitigan, M |title=Diagnosis and treatment of lichen planus |journal=American family physician|date=Jul 1, 2011|volume=84|issue=1|pages=53–60|pmid=21766756|url=http://www.aafp.org/afp/2011/0701/p53.html#afp20110701p53-b6}}</ref><ref name=ANDREWS2006p223/><ref name="pmid17467854">{{cite journal |vauthors=Cevasco NC, Bergfeld WF, Remzi BK, de Knott HR |title=A case-series of 29 patients with lichen planopilaris: the Cleveland Clinic Foundation experience on evaluation, diagnosis, and treatment |journal=J. Am. Acad. Dermatol. |volume=57 |issue=1 |pages=47–53 |year=2007 |pmid=17467854 |doi=10.1016/j.jaad.2007.01.011}}</ref> * Hair. This variant causes [[cicatricial alopecia|inflammation of hair follicles]] and gradual replacement with scarring. About 10% of people with lichen planus have the scalp or nail variants of the condition.<ref name="Usatine 2011" /> Other variants may include: * ''Lichen planus pemphigoides'' characterized by the development of tense blisters atop lesions of lichen planus or the development vesicles de novo on uninvolved skin.<ref name=FITZPATRICK2003p471>{{cite book |editor1-first=Irwin M. |editor1-last=Freedberg |title=Fitzpatrick's dermatology in general medicine |year=2003 |publisher=McGraw-Hill |location=New York, NY |isbn=0-07-138076-0 |page=471 |edition=6th}}</ref> * ''Keratosis lichenoides chronica'' (also known as "Nekam's disease") is a rare dermatosis characterized by violaceous papular and nodular lesions, often arranged in a linear or reticulate pattern on the dorsal hands and feet, extremities, and buttock, and some cases manifests by sorrheic dermatitis like eruption on the scalp and face, also palmo plantar keratosis has been reported.<ref name=BOLOGNIA2008 /><ref name=FITZPATRICK2003p472>{{cite book |editor1-first=Irwin M. |editor1-last=Freedberg |title=Fitzpatrick's dermatology in general medicine |year=2003 |publisher=McGraw-Hill |location=New York, NY |isbn=0-07-138076-0 |page=472 |edition=6th}}</ref><ref name=ANDREWS2006p224>{{cite book |first1=William D. |last1=James |first2=Dirk M. |last2=Elston |first3=Timothy G. |last3=Berger |title=Andrews' Diseases of the skin : clinical dermatology |publisher=Saunders/ Elsevier |location=London |isbn=1-4377-0314-3 |edition=11th |page=224}}</ref> * ''Lichenoid keratoses'' (also known as "Benign lichenoid keratosis," and "Solitary lichen planus"<ref name=BOLOGNIA2008 />) is a cutaneous condition characterized by brown to red scaling maculopapules, found on sun-exposed skin of extremities.<ref name=BOLOGNIA2008 /><ref name=FITZPATRICK2003p473>{{cite book |editor1-first=Irwin M. |editor1-last=Freedberg |title=Fitzpatrick's dermatology in general medicine |year=2003 |publisher=McGraw-Hill |location=New York, NY |isbn=0-07-138076-0 |page=473 |edition=6th}}</ref> Restated, this is a cutaneous condition usually characterized by a solitary dusky-red to violaceous papular skin lesion.<ref name=ANDREWS2006p639>{{cite book |first1=William D. |last1=James |first2=Dirk M. |last2=Elston |first3=Timothy G. |last3=Berger |title=Andrews' Diseases of the skin : clinical dermatology |publisher=Saunders/ Elsevier |location=London |isbn=1-4377-0314-3 |edition=11th |page=639}}</ref> * ''Lichenoid dermatitis'' represents a wide range of cutaneous disorders characterized by lichen planus-like skin lesions.<ref name=BOLOGNIA2008 /><ref name=FITZPATRICK2003p473/> ===Mucosal lichen planus=== [[File:Lichen Planus Fig7.tiff|thumbnail|right|Lichen planus on the lips and the lateral border of the tongue]] Lichen planus affecting mucosal surfaces may have one lesion or be multifocal.<ref name="Ebrahimi 2012">{{cite journal|last=Ebrahimi|first=M|author2=Lundqvist, L |author3=Wahlin, YB |author4= Nylander, E |title=Mucosal lichen planus, a systemic disease requiring multidisciplinary care: a cross-sectional clinical review from a multidisciplinary perspective |journal=Journal of lower genital tract disease|date=October 2012|volume=16|issue=4|pages=377–80|pmid=22622344|doi=10.1097/LGT.0b013e318247a907}}</ref> Examples of lichen planus affecting mucosal surfaces include:<ref name="Ebrahimi 2012"/> * ''[[Esophagus|Esophageal]] lichen planus'', affecting the esophageal mucosa. This can present with [[dysphagia|difficulty or pain when swallowing]] due to [[esophagitis|oesophageal inflammation]], or as the development of an [[esophageal stricture]]. It has also been hypothesized that it is a precursor to squamous cell carcinoma of the esophagus.<ref name=YAMADA2009>{{cite book|vauthors=Yamada T, Alpers DH |title=Textbook of gastroenterology|year=2009|publisher=Blackwell Pub.|location=Chichester, West Sussex|isbn=978-1-4051-6911-0|edition=5th|page=3304|display-authors=etal}}</ref><ref>{{cite journal|last=Chandan|first=VS|author2=Murray, JA |author3=Abraham, SC |title=Esophageal lichen planus |journal=Archives of pathology & laboratory medicine|date=June 2008|volume=132|issue=6|pages=1026–9|pmid=18517264|doi=10.1043/1543-2165(2008)132[1026:ELP]2.0.CO;2}}</ref> * ''Genital lichen planus,'' which may cause lesions on the [[glans penis]] or skin of the scrotom in males, and the vulva or vagina in females.<ref name="Usatine 2011" /> Symptoms may include [[lower urinary tract symptom]]s associated with [[stenosis]] of the [[urethra]], [[dyspareunia|painful sexual intercourse]], and itching.<ref name="Usatine 2011" /> In females, ''Vulvovaginal-gingival syndrome,'' is severe and distinct variant affecting the [[vulva]], [[vagina]], and gums, with complications including scarring, vaginal stricture formation,<ref>{{cite journal|last=Panagiotopoulou|first=N|author2=Wong, CS |author3=Winter-Roach, B |title=Vulvovaginal-gingival syndrome.|journal=Journal of obstetrics and gynaecology : the journal of the Institute of Obstetrics and Gynaecology|date=April 2010|volume=30|issue=3|pages=226–30|pmid=20373919|doi=10.3109/01443610903477572}}</ref> or vulva destruction.<ref name="Schlosser 2010">{{cite journal|last=Schlosser|first=BJ|title=Lichen planus and lichenoid reactions of the oral mucosa.|journal=Dermatologic therapy|date=May–Jun 2010|volume=23|issue=3|pages=251–67|doi=10.1111/j.1529-8019.2010.01322.x|pmid=20597944}}</ref> The corresponding syndrome in males, affecting the glans penis and gums, is the ''peno-gingival syndrome''.<ref name=BOLOGNIA2008 /> It is associated with [[HLA-DQB1]].<ref name=BOLOGNIA2008 /><ref name="Nico 2011">{{cite journal|last=Nico|first=MM|author2=Fernandes, JD |author3=Lourenço, SV |title=Oral lichen planus.|journal=Anais brasileiros de dermatologia|date=Jul–Aug 2011|volume=86|issue=4|pages=633–41; quiz 642–3|pmid=21987126|url=http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0365-05962011000400002&lng=en&nrm=iso&tlng=en}}</ref> ====Oral lichen planus==== Oral lichen planus (also termed ''oral mucosal lichen planus''),<ref>{{cite journal|last=Alam|first=F|author2=Hamburger, J |title=Oral mucosal lichen planus in children.|journal=International journal of paediatric dentistry / the British Paedodontic Society [and] the International Association of Dentistry for Children|date=May 2001|volume=11|issue=3|pages=209–14|pmid=11484471}}</ref> is a form of mucosal lichen planus, where lichen planus involves the [[oral mucosa]], the lining of the mouth. This may occur in combination with other variants of lichen planus.<ref name="Scully 2013" /> Six clinical forms of oral lichen planus are recognized:<ref name="Scully 2013">{{cite book|last=Scully C|title=Oral and maxillofacial medicine : the basis of diagnosis and treatment|year=2008|publisher=Churchill Livingstone|location=Edinburgh|isbn=9780702049484|edition=3rd|pages=192–199}}</ref> * ''Reticular'', the most common presentation of oral lichen planus,<ref name="Thongprasom 2011" /> is characterised by the net-like or spider web-like appearance of lacy white lines, oral variants of [[Wickham striae|Wickham's straiae]].<ref name="Scully 2013" /> This is usually asymptomatic.<ref name="Thongprasom 2011" /> * ''Erosive/ulcerative'', the second most common form of oral lichen planus,<ref name="Thongprasom 2011" /> is characterised by [[mouth ulcer|oral ulcers]] presenting with persistent, irregular areas of [[erythema|redness]], ulcerations and erosions covered with a yellow slough.<!-- <ref name="Scully 2013" /> --> This can occur in one or more areas of the mouth. In 25% of people with erosive oral lichen planus, the gums are involved, described as [[desquamative gingivitis]] (a condition not unique to lichen planus). <!-- <ref name="Scully 2013" /> --> This may be the initial or only sign of the condition.<ref name="Scully 2013" /> * ''Papular,'' with white papules. * ''Plaque-like'' appearing as a white patch which may resemble [[leukoplakia]].<ref name="Scully 2013" /> * ''Atrophic,'' appearing as areas. Atrophic oral lichen planus may also manifest as desquamative gingivitis.<ref name="Scully 2013" /> * ''Bullous,'' appearing as fluid-filled vesicles which project from the surface. These types often coexist in the same individual. Oral lichen planus tends to present bilaterally as mostly white lesions on the [[buccal mucosa|inner cheek]],<ref name="Thongprasom 2011" /> although any mucosal site in the mouth may be involved. Other sites, in decreasing order of frequency, may include the tongue, lips, gingivae, floor of the mouth, and very rarely, the palate.<ref name="Thongprasom 2011" /> Generally, oral lichen planus tends not to cause any discomfort or pain, although some people may experience soreness when eating or drinking acidic or spicy foodstuffs or beverages.<ref name="Scully 2013" /> When symptoms arise, they are most commonly associated with the atrophic and ulcerative subtypes. These symptoms can include a burning sensation to severe pain.<ref name="Thongprasom 2011" /> Lichen planus, particularly when concomitant oral or genital lesions occur, significantly affects patients’ quality of life. ==Causes== The cause of lichen planus is unknown,<ref name=TG2009 /><ref name="Nico 2011" /><ref name="Roopashree 2010">{{cite journal|last=Roopashree|first=MR|author2=Gondhalekar, RV |author3=Shashikanth, MC |author4=George, J |author5=Thippeswamy, SH |author6= Shukla, A |title=Pathogenesis of oral lichen planus--a review.|journal=Journal of oral pathology & medicine : official publication of the International Association of Oral Pathologists and the American Academy of Oral Pathology|date=November 2010|volume=39|issue=10|pages=729–34|pmid=20923445|doi=10.1111/j.1600-0714.2010.00946.x}}</ref> but it is not contagious and does not involve any known [[pathogen]].<ref name=DAVIDSONS2009 /> It is thought to be a [[T cell]] mediated [[autoimmunity|autoimmune]] reaction (where the body's immune system targets its own tissues).<ref name="Thongprasom 2011" /> This autoimmune process triggers [[apoptosis]] of the [[epithelium|epithelial cells]].<ref name="Thongprasom 2011" /> Several [[cytokine]]s are involved in lichen planus, including [[tumor necrosis factor alpha]], [[interferon gamma]], [[IL1A|interleukin-1 alpha]], [[interleukin 6]], and [[interleukin 8]].<ref name="Thongprasom 2011" /> This autoimmune, T cell mediated, process is thought to be in response to some [[antigen]]ic change in the oral mucosa, but a specific antigen has not been identified.<ref name="Thongprasom 2011" /> Where a causal or triggering agent is identified, this is termed a '''lichenoid reaction''' rather than lichen planus. These may include:<ref name="Bruch 2010" /> * Drug reactions, with the most common inducers including gold salts, [[beta blocker]]s, traditional [[malaria|antimalarials]] (e.g. [[quinine]]), [[thiazide diuretics]], [[furosemide]], [[spironolactone]], [[metformin]] and [[penicillamine]].<ref name=DAVIDSONS2009>{{cite book|first=the editors Nicki R. Colledge, Brian R. Walker, Stuart H. Ralston ; illustrated by Robert Britton|title=Davidson's principles and practice of medicine.|year=2010|publisher=Churchill Livingstone/Elsevier|location=Edinburgh|isbn=978-0-7020-3085-7|pages=1265–1266|edition=21st}}</ref> * Reactions to amalgam (metal alloys) fillings (or when they are removed/replaced),<ref name=ISSA2004>{{cite journal|last=Issa|first=Y|author2=Brunton, PA |author3=Glenny, AM |author4= Duxbury, AJ |title=Healing of oral lichenoid lesions after replacing amalgam restorations: a systematic review.|journal=Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics|date=November 2004|volume=98|issue=5|pages=553–65|pmid=15529127|doi=10.1016/j.tripleo.2003.12.027}}</ref> * [[Graft-versus-host disease]] lesions, which chronic lichenoid lesions seen on the palms, soles, face and upper trunk after several months.<ref name=DAVIDSONS2009 /> * Hepatitis, specifically [[hepatitis B]] and [[hepatitis C]] infection, and [[primary biliary cirrhosis]].<ref name=ANDREWS2006p220/><ref name=DAVIDSONS2009 /> It has been suggested that lichen planus may respond to [[Stress (medicine)|stress]], where lesions may present during times of stress. Lichen planus can be part of [[Grinspan's syndrome]].{{Citation needed|date=August 2013}} It has also been suggested that mercury exposure may contribute to lichen planus.<ref>{{cite journal |vauthors=Dunsche A, Frank MP, Lüttges J, etal |title=Lichenoid reactions of murine mucosa associated with amalgam |journal=The British Journal of Dermatology |volume=148 |issue=4 |pages=741–8 | date=April 2003 |pmid=12752133 |doi=10.1046/j.1365-2133.2003.05229.x}}</ref> ==Diagnosis== Lichen planus lesions are diagnosed clinically by their "lichen-like" appearance.<ref name=TG2009 /> A [[biopsy]] can be used to rule out conditions that may resemble lichen planus, and can pick up any secondary malignancies.<ref name="Kerawala 2010" /> ===Histopathology=== [[File:lichen planus intermed mag.jpg|thumb|[[Micrograph]] of lichen planus. [[H&E stain]].]] Lichen planus has a [[pathognomonic|unique]] microscopic appearance that is similar between cutaneous, mucosal and oral. A [[Periodic acid-Schiff stain]] of the biopsy may be used to visualise the specimen. [[Histology|Histological]] features seen include:<ref name=SCULLY1985 /> * thickening of the [[stratum corneum]] both with nuclei present ([[parakeratosis]]) and without ([[orthokeratosis]]). Parakeratosis is more common in oral variants of lichen planus. * thickening of the [[stratum granulosum]] * thickening of the [[stratum spinosum]] ([[acanthosis]]) with formation of colloid bodies (also known as Civatte bodies, Sabouraud bodies) that may stretch down to the lamina propria. * liquefactive degeneration of the [[stratum basale]], with separation from the underlying [[lamina propria]], as a result of desmosome loss, creating small spaces (Max Joseph spaces). * Infiltration of [[T cell]]s in a band-like pattern into the [[dermis]]<ref name="Thongprasom 2011" /> "hugging" the basal layer. * Development of a "saw-tooth" appearance of the [[rete pegs]], which is much more common in non-oral forms of lichen planus. ===Differential diagnosis=== The [[differential diagnosis]] for OLP includes: * Other oral vesiculo-ulcerative conditions such as [[Pemphigus vulgaris]] and [[Benign mucous membrane pemphigoid]] * [[Lupus erythematosus]], with lesions more commonly occur on the palate and appear as centrally ulcerated or erythematous with radiating white striae. In contrast, OLP and lichenoid reactions rarely occur on the palate, and the striae are randomly arranged rather than radial.<ref name="Odell 2010">{{cite book|last=Odell EW (Editor)|title=Clinical problem solving in dentistry|year=2010|publisher=Churchill Livingstone|location=Edinburgh|isbn=9780443067846|pages=159–162, 192|edition=3rd}}</ref> * [[Chronic ulcerative stomatitis]] * Frictional [[keratosis]] and [[Morsicatio buccarum]] (chronic [[cheek]] biting) * Oral [[leukoplakia]] * [[Oral candidiasis]] ==Treatment== <!-- ONLY SOURCES WHICH MEET THE SOURCING POLICY FOR MEDICAL CONTENT ON WIKIPEDIA TO BE INCLUDED (SEE: http://en.wikipedia.org/wiki/MEDRS ), CONTENT BASED ON UNSUITABLE SOURCES WILL BE REMOVED --> There is no cure for lichen planus,<ref name="Thongprasom 2011" /> and so treatment of cutaneous and oral lichen planus is for symptomatic relief or due to cosmetic concerns.<ref name=TG2009 /><ref name="Thongprasom 2011" /><ref name="Kerawala 2010" /> When medical treatment is pursued, first-line treatment typically involves [[corticosteroid]]s,<ref name=TG2009 /> and removal of any triggers.<ref name=ISSA2004 /> Without treatment, most lesions will spontaneously resolve within 6–9 months for cutaneous lesions,<ref name=TG2009 /> and longer for mucosal lesions.<ref name=SCULLY1985>{{cite journal|last=Scully|first=C.|author2=El-Kom, M. |title=Lichen planus: review and update on pathogenesis|journal=Journal of Oral Pathology and Medicine|date=1 July 1985|volume=14|issue=6|pages=431–458|doi=10.1111/j.1600-0714.1985.tb00516.x}}</ref> Recently, it was hypothesized that the interferon gamma/CXCL10 axis could be a target to reverse inflammation.<ref name=":0" /> ===Cutaneous lichen planus=== Many different treatments have been reported for cutaneous lichen planus, however there is a general lack of evidence of efficacy for any treatment.<ref name=GOROUHI2009 /><ref name="CRIBIER1998">{{cite journal|last=Cribier|first=B|date=December 1998|title=Treatment of lichen planus. An evidence-based medicine analysis of efficacy.|journal=Archives of dermatology|volume=134|issue=12|pages=1521–30|doi=10.1001/archderm.134.12.1521|pmid=9875189|author2=Frances, C|author3=Chosidow, O}}</ref> Treatments tend to be prolonged, partially effective and disappointing.<ref name=GOROUHI2009 /> The mainstay of localized skin lesions is topical steroids. Additional treatments include [[retinoid]]s such as [[Acitretin]], or sulfosalazin. Narrow band UVB phototherapy or systemic PUVA therapy are known treatment modalities for generalized disease. However, there is striking paucity of evidence regarding therapy, since randomized clinical trials on the medical or physical treatment of LP are lacking.<ref>{{Cite journal|last=Antiga|first=E.|last2=Caproni|first2=M.|last3=Parodi|first3=A.|last4=Cianchini|first4=G.|last5=Fabbri|first5=P.|date=2014-12-01|title=Treatment of cutaneous lichen planus: an evidence based analysis of efficacy by the Italian Group for Cutaneous Immunopathology|url=http://www.ncbi.nlm.nih.gov/pubmed/?term=25664824|journal=Giornale Italiano Di Dermatologia E Venereologia: Organo Ufficiale, Società Italiana Di Dermatologia E Sifilografia|volume=149|issue=6|pages=719–726|issn=0392-0488|pmid=25664824}}</ref> ===Oral lichen planus=== Reassurance that the condition is benign, elimination of precipitating factors and improving [[oral hygiene]] are considered initial management for symptomatic OLP, and these measures are reported to be useful.<ref name="Thongprasom 2011" /> Treatment usually involves [[topical medication|topical]] [[corticosteroids]] (such as [[betamethasone]],<!-- <ref name="Thongprasom 2011" /> --> [[clobetasol]],<!-- <ref name="Thongprasom 2011" /> --> [[dexamethasone]],<!-- <ref name="Thongprasom 2011" /> --> and [[triamcinolone]]<!-- <ref name="Thongprasom 2011" /> -->) and [[analgesic]]s, or if these are ineffective and the condition is severe, the systemic corticosteroids may be used. [[Calcineurin inhibitor]]s (such as [[pimecrolimus]],<!-- <ref name="Thongprasom 2011" /> --> [[tacrolimus]]<!-- <ref name="Thongprasom 2011" /> -->) or [[cyclosporin]]<!-- <ref name="Thongprasom 2011" /> and [[retinoid]]s (such as [[tretinoin]]--><!-- <ref name="Thongprasom 2011" /> -->) are sometimes used.<ref name="Thongprasom 2011" /> ==Prognosis== In contrast to cutaneous lichen planus, lichen planus lesions in the mouth may persist for many years,<ref name="Kerawala 2010" /> and tend to be difficult to treat, with relapses being common.<ref name="Nico 2011" /> Atrophic/erosive lichen planus is associated with a small risk of malignant transformation,<ref name="Kerawala 2010" /> and so people with OLP tend to be kept on long term review to detect any potential change early. Sometimes OLP can become secondarily infected with Candida organisms.{{citation needed|date=August 2013}} ==Epidemiology== The overall [[prevalence]] of lichen planus in the general population is about 0.1 - 4%.<ref name="Usatine 2011" /> It generally occurs more commonly in females, in a ratio of 3:2, and most cases are diagnosed between the ages of 30 and 60, but it can occur at any age.<ref name="Usatine 2011" /><ref>{{cite journal |vauthors=Yu TC, Kelly SC, Weinberg JM, Scheinfeld NS |title=Isolated lichen planus of the lower lip |journal=Cutis |volume=71 |issue=3 |pages=210–2 | date=March 2003 |pmid=12661749}}</ref> Oral lichen planus is relatively common,<ref name="Nico 2011" /> It is one of the most common mucosal diseases. The prevalence in the general population is about 1.27-2.0%,<ref name="Thongprasom 2011" /><ref name="Kerawala 2010">{{cite book|veditors=Kerawala C, Newlands C |title=Oral and maxillofacial surgery|year=2010|publisher=Oxford University Press|location=Oxford|isbn=978-0-19-920483-0|pages=412–413}}</ref> and it occurs more commonly in middle aged people.<ref name="Thongprasom 2011">{{cite journal|last=Thongprasom|first=K|author2=Carrozzo, M |author3=Furness, S |author4= Lodi, G |title=Interventions for treating oral lichen planus.|journal=The Cochrane database of systematic reviews|date=Jul 6, 2011|issue=7|pages=CD001168|doi=10.1002/14651858.CD001168.pub2|pmid=21735381}}</ref> OLP in children is rare. About 50% of females with oral lichen planus were reported to have undiagnosed vulvar lichen planus.<ref name="Usatine 2011" /> ==History== Lichen planus was first reported in 1869 by [[Erasmus Wilson]].<ref name=SCULLY1985 /> ==Notes== {{notelist}} ==References== {{Reflist|2}} ==External links== {{commons category}} * {{DMOZ|Health/Conditions_and_Diseases/Skin_Disorders/Lichen_Planus/}} {{Diseases of the skin and appendages by morphology}} {{Papulosquamous disorders}} {{oral pathology}} {{DEFAULTSORT:Lichen Planus}} [[Category:Lichenoid eruptions]] [[Category:Conditions of the mucous membranes]] [[Category:Hepatitis C virus-associated diseases]] [[Category:Autoimmune diseases]] [[Category:Oral mucosal pathology]]'