32: Lichen Planus Flashcards
What are the classic features of Lichen Planus?
The classic features of Lichen Planus, known as the 4P’s, are: 1. Purple 2. Polygonal 3. Pruritic 4. Papules
What is the role of CD8 T cells in the pathogenesis of Lichen Planus?
CD8 T cells serve as the effector cells in Lichen Planus, involved in initial antigen recognition, release of cytokines, and inducing apoptosis in keratinocytes.
What factors are suggested to potentially trigger Lichen Planus?
Potential triggers for Lichen Planus include contact sensitizers (e.g., metals), drugs (biologics, TNF-α inhibitors), and alloantigens in lichenoid GVHD.
What is the significance of lymphocyte activation in Lichen Planus?
Lymphocyte activation involves CD8 T cells releasing cytokines, induces expression of inflammatory chemokines, and affects the balance between activation and downregulation.
What are the possible mechanisms of keratinocyte apoptosis in Lichen Planus?
Possible mechanisms include Granzyme B activation of caspase-3 and TNF-α interaction with its receptor leading to matrix component expression.
What role do T regulatory cells play in oral lichen planus?
T regulatory cells correlate with disease subtype and activity, disrupting dendritic cell and allogeneic T-cell interactions.
What is the prevalence of oral lichen planus and its demographic characteristics?
The prevalence varies from 0.1% to 4%, most common in individuals aged 30-60 years, with no clear sexual or racial predilection.
What are the clinical features of cutaneous lichen planus?
Cutaneous lichen planus is characterized by well-marginated dull red-violet papules, Wickham striae, symmetrical distribution, and extreme pruritus.
What is the significance of the Koebner phenomenon in lichen planus?
The Koebner phenomenon refers to trauma-induced exposure of dendritic cells to endogenous peptides, stimulating Type 1 interferons and propagating the disease.
What are the familial and non-familial associations of lichen planus?
Familial lichen planus is associated with strong family history and specific HLA haplotypes, while non-familial associations include other HLA types.
What is the most likely diagnosis for a patient with dull red-violet papules on their wrists and legs?
The most likely diagnosis is classic lichen planus. Histological features include hyperkeratosis, wedge-shaped hypergranulosis, and lymphohistiocytic infiltrate.
What is the largest demographic affected by Lichen Planus according to US studies?
The largest predominance of Lichen Planus is found in African American children.
What are the common clinical and histological involvements of Lichen Planus in adults?
In adults, skin involvement occurs in 42-60% of cases, and oral involvement occurs in 17-30% of cases.
What are the characteristics of Annular Lichen Planus?
Annular Lichen Planus is commonly found in the penis/scrotum area.
What distinguishes Linear Lichen Planus from other forms?
Linear Lichen Planus is characterized by post-zygomatic somatic mutations and occurs when dermatomal lines are not followed.
What are the key features of Hypertrophic Lichen Planus?
Hypertrophic Lichen Planus is marked by lesions on the anterior shin, very pruritic symptoms, and thick elevated purple-red plaques.
What is the most common location for Atrophic Lichen Planus?
Atrophic Lichen Planus is most commonly found in the proximal lower extremities and trunk.
What are the characteristics of Vesicobullous Lichen Planus?
Vesicobullous Lichen Planus is secondary to exuberant inflammatory response, more common in lower extremities, and may lead to erosion and ulceration.
What are the symptoms associated with Erosive and Ulcerative Lichen Planus?
Erosive and Ulcerative Lichen Planus is associated with pain and scarring, commonly in the feet and oral cavity.
What are the distinct variants of Follicular Lichen Planus?
Follicular Lichen Planus has three distinct variants: Lichen planopilaris, Frontal fibrosing alopecia.
What are the characteristics of Lichen Planus Pigmentosus?
Lichen Planus Pigmentosus features hyperpigmented dark brown macules in sun-exposed areas, common in darker skin.
What is the most common form of Mucosal Lichen Planus and its characteristics?
The reticular form is the most common, typically asymptomatic, involving the buccal mucosa and tongue.
What are the common sites and symptoms of Esophageal Lichen Planus?
Commonly affects the proximal esophagus, prevalent in middle-aged women, with symptoms like dysphagia and odynophagia.
What is Pseudopelade of Brocq and its clinical significance?
Pseudopelade of Brocq is a clinical syndrome of scarring alopecia characterized by absence of distinct pathologic features.
What are the characteristics of Frontal Fibrosing Alopecia?
It involves progressive frontotemporal recession due to inflammatory destruction of hair follicles, more common in postmenopausal women.
What syndrome should be considered for a patient with cicatricial alopecia of the scalp and nonscarring alopecia of the axilla?
Graham-Little-Piccardi-Lassueur syndrome should be considered.
What additional diagnostic steps should be taken for a patient with oral lichen planus reporting dysphagia?
Diagnostic steps include systemic immunosuppression with oral corticosteroids and monitoring for esophageal strictures.
What variant of lichen planus is characterized by hyperpigmented dark brown macules?
This is lichen planus pigmentosus. Differential diagnoses include ashy dermatosis and erythema dyschromicum perstans.
What are the common findings associated with Lichen Planus of the nails?
Common findings include diffuse nail involvement, longitudinal ridging, distal nail splitting, onycholysis, and atrophic nail plates.
What is the significance of dorsal pterygium in Lichen Planus of the nails?
Dorsal pterygium is characterized by forward growth of the eponychia adhering to the proximal nail plate and is irreversible.
What are the long-term sequelae associated with conjunctival Lichen Planus?
Long-term sequelae include corneal scarring, symblepharon, blindness, and lacrimal duct stenosis.
What are the major forms of Lichen Planus of the nails?
The three major forms are classic nail Lichen Planus, 20 nail dystrophy, and idiopathic atrophy of the nails.
What is the clinical presentation of Inverse Lichen Planus?
Inverse Lichen Planus presents as red-brown discrete papules and flat-topped plaques, commonly affecting flexural areas.
What are the differential diagnoses for Lichen Planus of the nails?
Differential diagnoses include psoriasis, alopecia areata, atopic dermatitis, and immunobullous diseases.
What syndrome is characterized by erythema and erosions of the gingivae and vulva?
This is vulvovaginal gingival syndrome, with long-term sequelae including fibrosis and stricture.
What rare manifestation should be considered for a patient with persistent unexplained otorrhea?
Otic lichen planus should be considered, with potential complications including hearing loss and canal stenosis.
What variant of lichen planus presents with red-brown papules in the axillae and groin?
This is inverse lichen planus, most commonly reported in whites, Asians, and Tunisians.
What diagnostic tests can distinguish cicatricial conjunctivitis from cicatricial pemphigoid?
Diagnostic tests include direct immunofluorescence, indirect immunofluorescence, and serologies for antibodies.
What condition is characterized by forward growth of the eponychium adhering to the proximal nail plate?
This condition is called pterygium. Dorsal pterygium is irreversible and does not improve with treatment.
What is the condition called when eponychium adheres to the proximal nail plate, and is it reversible?
This condition is called pterygium. Dorsal pterygium is irreversible and does not improve with treatment.
What syndrome is associated with lichen planus presenting with erythema and erosions of the gingivae and vulva?
This is vulvovaginal gingival syndrome. Long-term sequelae include fibrosis and stricture.
What are the common sites for ulcerated lichen planus?
Ulcerated lichen planus is commonly seen on the internal plantar arch of the feet and the thenar and hypothenar eminence of the hand. Involvement of the fingertips is uncommon.
What are the characteristics of drug-induced lichen planus?
Drug-induced lichen planus can present as localized or generalized eczematous papules and plaques, often associated with hyperpigmentation and alopecia. Wickham striae and mucous membrane involvement are rare. Eruptions are symmetrical on the trunk and extremities, with less common flexural involvement. Specific drugs can lead to mucous membrane involvement and a photodistributed pattern.
What is the latency period for drug-induced lichen planus and its resolution time?
The latency period for drug-induced lichen planus varies from months to more than a year. Most cases often resolve in 3-4 months, except for those induced by Gold, which may require years for resolution.
What are the features of LP-Lupus overlap?
LP-Lupus overlap is characterized by red-violet atrophic plaques and patches with hypopigmentation, telangiectasia, and minimal scale. Most common sites include the dorsal aspect of the extremities, hands, and nails (can have anonychia). Classic features of LP and LE are absent, and some individuals may develop SLE. Lab findings may show weakly positive ANA.
What are the features of LP Pemphigoides?
LP Pemphigoides exhibits features of both lichen planus (LP) and bullous pemphigoid (BP).
What is the likely diagnosis for a patient with lichen planus presenting with a photodistributed pattern of lesions after starting a new medication?
The likely diagnosis is drug-induced lichen planus. Commonly implicated drugs include immune checkpoint inhibitors like ipilimumab, pembrolizumab, and nivolumab.
What are the key clinical and serologic features that differentiate true LP pemphigoides from concomitant LP and BP?
LP affects individuals in the 5th to 7th decades. BP affects individuals after the 7th decade. LP pemphigoides occurs in younger individuals, typically in the 4th to 5th decades. Blisters of LP pemphigoides may occur on top of lichenoid lesions or on normal appearing skin. Prognosis is good and responsive to conventional treatment.
What is the histological finding associated with Keratosis Lichenoides (Nekam Disease)?
Histopathology shows brisk LTR with parakeratosis and neutrophils in the crust.
What are the clinical characteristics of Lichenoid GVHD?
Acute GVHD is TH2 driven. Chronic GVHD is TH1/TH17 driven, involving IFN-γ and IL-17 CD8 cells. Characterized by classic lichenoid papules with prominent follicular involvement of the head and neck, as well as oral manifestations. Associated findings include onycholysis and cicatricial alopecia.
What are the differential diagnoses for Lichenoid Keratosis?
Differential diagnoses include Lichen Planus (LP), Lichen Simplex Chronicus (LSC), Lupus Erythematosus (LE), Seborrheic keratosis, and Actinic keratosis.
What liver diseases are associated with Lichen Planus?
Autoimmune chronic active hepatitis, Primary biliary cirrhosis, Postviral chronic active hepatitis, and Hepatitis C virus (associated with oral LP, not pure cutaneous LP; may relate to HLA-DR6 haplotype).
What is the likely diagnosis for a patient with lichen planus presenting with a single non-pruritic brown scaling plaque on sun-exposed skin?
The likely diagnosis is lichenoid keratosis. It differs histologically by showing parakeratosis and remnants of lentigo, seborrheic keratosis, or actinic keratosis.
What type of lichen planus is most commonly associated with hepatitis C?
Oral lichen planus is most commonly associated with hepatitis C.
What are the risk factors associated with malignant transformation in oral lichen planus (LP)?
The risk factors for malignant transformation in oral lichen planus include long-standing disease, erosive or atrophic types, tobacco use, disease with esophageal involvement, and HPV infection.
What are the common sites for cancer associated with oral lichen planus?
The common sites for cancer associated with oral lichen planus are the tongue (most common), buccal mucosa, gingiva, and lip.
What is the clinical appearance of lesions in oral lichen planus?
The clinical appearance of lesions in oral lichen planus includes indurated, nonhealing ulcers, exophytic lesions with a keratotic surface, and red atrophic plaques.
What laboratory tests are recommended for diagnosing lichen planus?
Recommended laboratory tests for diagnosing lichen planus include Complete blood count (CBC), Patch test, Lipid panel, Thyroid function tests, and HCV testing.
What are the two major pathologic findings in lichen planus?
The two major pathologic findings in lichen planus are basal epidermal keratinocyte damage and lichenoid interface lymphocytic reaction.
What are the classic histological features of lichen planus?
The classic histological features of lichen planus include hyperkeratosis, wedge-shaped areas of hypergranulosis, and elongation of rete ridges resembling a sawtooth pattern. Dense, continuous, bandlike lymphohistiocytic infiltrate at the DEJ, multiple apoptotic cells or colloid-hyaline (Civatte) bodies, and presence of eosinophilic colloid bodies.
What is the concern for a patient with oral lichen planus who has a history of tobacco use and presents with indurated, nonhealing ulcers?
The concern is malignant transformation. Commonly affected sites include the tongue, buccal mucosa, gingiva, and lip.
What are the histological features of hypertrophic lichen planus?
Hypertrophic lichen planus is characterized by hyperkeratosis, acanthosis, papillomatosis, and thickened collagen bundles in the dermis.
What is the significance of Direct Immunofluorescence (DIF) in diagnosing lichen planus?
DIF plays a crucial role in diagnosing atypical lichen planus variants, particularly ulcerative and vesiculobullous forms. The mouth floor and ventral side of the tongue show the highest sensitivity in DIF.
What is the typical clinical course and prognosis of lichen planus?
Lichen planus typically resolves within 1-2 years but may have relapses in 20% of cases. The mean duration of oral lichen planus is approximately 5 years.
What are the first-line treatment options for cutaneous lichen planus?
The first-line treatment options for cutaneous lichen planus include high potency topical corticosteroids and topical calcineurin inhibitors (e.g., Tacrolimus 0.1% ointment).
What are the differential diagnoses for lichen planus?
Differential diagnoses for lichen planus include classic psoriasis, lichen simplex chronicus, drug eruptions, follicular lichen, mucosal lichen, and other conditions like pemphigoid and pemphigus.
What is the likely diagnosis for a patient with lichen planus presenting with a brisk lymphocytic interface reaction and eosinophils on histology?
The likely diagnosis is a lichenoid drug eruption, as eosinophils are present in two-thirds of such cases.
What biopsy technique is recommended for diagnosing lichen planopilaris?
A dermoscopic-driven biopsy showing perifollicular erythema and scaling is recommended for a definitive diagnosis of lichen planopilaris.
What type of lichen planus is likely for a patient with brisk lymphocytic interface reaction and parakeratosis on histology?
This is likely mucosal lichen planus, as parakeratosis is commonly seen in mucosal sites.
What is the most effective topical therapy for oral lichen planus (LP)?
The most effective topical therapy for oral LP is topical corticosteroids, which may be used with topical steroids in refractory cases of cutaneous LP.
What are the first-line systemic treatments for oral lichen planus?
The first-line systemic treatments for oral lichen planus include oral corticosteroids, oral retinoids, antimalarials, methotrexate, mycophenolate mofetil, azathioprine, and cyclosporine.
What is the role of phototherapy in the treatment of lichen planus?
Phototherapy (UVB 3x/week) is used in the treatment of lichen planus as it exposes dendritic cells (DCs) to UV light, impairing their interaction with T cells, altering cytokine expression, and leading to T-cell suppression and apoptosis.
What are some systemic therapies that target lymphocytes for refractory and ulcerative lichen planus?
Systemic therapies that target lymphocytes for refractory and ulcerative lichen planus include methotrexate, mycophenolate mofetil (MMF), and azathioprine.
What are the recommended skin-directed therapies for oral lichen planus?
Recommended skin-directed therapies for oral lichen planus include topical corticosteroids, occlusive materials, topical calcineurin inhibitors, retinoids, and intralesional corticosteroids.
What are the topical therapies for oral lichen planus?
Topical therapies include clobetasol propionate 0.05%, fluocinonide 0.1%, and topical calcineurin inhibitors like tacrolimus 0.1% ointment.
[page 10]
What is the first-line systemic treatment for hypertrophic lichen planus?
The first-line systemic treatment for hypertrophic lichen planus is acitretin (30 mg/day for 8 weeks).
[page 10]
What are the first-line therapies for Nail Lichen Planus?
The first-line therapies for Nail Lichen Planus include ultrapotent topical corticosteroids (5-10 mg/mL weekly) and intralesional corticosteroids.
What systemic therapies are commonly used for Frontal Fibrosing Alopecia?
The most commonly used and most effective systemic therapies for Frontal Fibrosing Alopecia include finasteride (2-5 mg/day for 12-18 months) and dutasteride (0.5 mg every 1-7 days).
What is the goal of treatment for Nail Lichen Planus?
The goal of treatment for Nail Lichen Planus is to reduce inflammatory cells within the nail and prevent irreversible pterygium.
What are the skin-directed therapies for Frontal Fibrosing Alopecia?
The skin-directed therapies for Frontal Fibrosing Alopecia include intralesional corticosteroids (10-20 mg/mL).
What are the first-line therapies for Frontal Fibrosing Alopecia?
The first-line therapies for Frontal Fibrosing Alopecia include oral 5-alpha reductase inhibitors, intralesional corticosteroids, and topical minoxidil.
What variant of lichen planus presents with scarring alopecia and perifollicular fibrosis?
This is lichen planopilaris. Recommended systemic therapies include hydroxychloroquine, oral corticosteroids, and methotrexate.
[page 11]
What is the most likely diagnosis for a 60-year-old woman with progressive frontotemporal hairline recession?
The most likely diagnosis is frontal fibrosing alopecia. Recommended systemic therapies include finasteride (2-5 mg/day for 12-18 months) or dutasteride (0.5 mg every 1-7 days).
[page 11]
⅔ of cases of LP present during _____ years - peak
onset at _____ years; age of onset earlier in _____.
30-60
55-74
women
Childhood LP comprise _____% of cases.
1-5
An arcuate grouping of individual papules coalescing to form a plaque with a central clearing is seen.
What variant of LP is this?
What are the most commonly involved sites?
Annular
penis and scrotum
Lesions form a pattern secondary to trauma.
0.2% may follow lines of Blaschko, related to postzygotic, somatic mutations.
What variant of LP is this?
Linear / blaschkoid / zosteriform (due to varicella zoster infection)
Lesions are highly pruritic, refractory to treatment, and
associated with relapse thickened, elevated, purple-red,
hyperkeratotic plaques and nodules; verrucal lesions; follicular accentuation, elevation, and chalk-like scale.
What variant of LP is this?
What are the most commonly involved sites?
What is a commonly associated condition?
Hypertrophic
Anterior shins and IPJs
Chronic venous insufficiency
It is an oligolesional disease with well-marginated, blue-white papules or plaques with central atrophy.
What variant of LP is this?
What are the most commonly involved sites?
What are some differentials?
Atrophic
Proximal lower extremity and trunk
Lichen sclerosus et atrophicus, MF
A rare variant of LP, secondary to an exuberant inflammatory response and an exaggerated Max-Joseph space; occurs in acute flares of LP.
What variant of LP is this?
What are the most commonly involved sites?
Vesicobullous
Lower extremities
A variant of LP with significant pain and scarring and other ectodermal involvement which aids in its diagnosis (scarring alopecia, loss of toenails).
What variant of LP is this?
What are the most commonly involved sites?
What is a commonly associated condition?
Erosive and ulcerative
Feet, oral cavity
SCC (chronic lesions)
A variant of LP found alone or in association with other cutaneous or mucosal forms of LP. Most commonly found on the scalp.
What are some subvariants?
Follicular
1. lichen planopilaris
2. frontal fibrosing alopecia
3. Gram-Little- Piccardi-Lassueur syndrome (GLPLS)
4. Lichen planus follicularis tumidus (rare: pruritic, red-violet pseudo-tumoral facial and posterior auricular plaques with yellow cysts; DDx: folliculotropic MF, and cutaneous LE)
LP variant presenting with hyperpigmented, dark-brown macules.
What variant of LP is this?
What are the most commonly involved sites?
What is a differential?
Lichen planus pigmentosus
Sun-exposed and flexural folds
Ashy dermatosis
LP variant found in subtropical countries affecting young individuals of Middle Eastern descent and is common in spring and summer months. Lesions are annular, well-marginated, hyperpigmented brown-violet, flat-topped plaques with a slightly rolled border and are minimally symptomatic.
What variant of LP is this?
What are the most commonly involved sites?
Actinic
Face > dorsal hands, arms, and nape of the neck (may be seen in non–sun-exposed areas, though!)
Most common findings of nail LP?
diffuse nail involvement with thinning, longitudinal ridging, and distal nail splitting
Classic finding in nail LP?
Pterygium
A variant of LP that appear as red-brown, discrete papules and flat-topped plaques and does not involve sun-exposed areas.
What variant of LP is this?
What are the most commonly involved sites?
Lichen planus pigmentosus inversus / Inverse
axillae, inframammary region and groin
A variant of LP with red-purple, scaly plaques with or without hyperkeratosis; absent Wickham striae.
What variant of LP is this?
What are the most commonly involved sites?
Palmoplantar
internal plantar arch on the feet and the thenar and hypothenar eminence on the hands
LP with a seborrheic distribution?
Keratosis lichenoides chronica (Nekam Disease)
LP with a solitary lesion?
Lichenoid keratosis
LP of the scalp that appears as a diffuse erythema with perifollicular hyperkeratosis and livid erythema; scarring.
What variant of LP is this?
What is the most commonly involved site?
Lichen planopilaris
Vertex scalp
Frontotemporal recession caused by inflammatory destruction of the hair follicles with a slow progression over years. 75% of women have a concomitant loss of the eyebrows.
What variant of LP is this?
What is the most commonly involved demographic?
Frontal fibrosing alopecia
postmenopausal women
Rare variant of LP characterized by cicatricial alopecia of the scalp & nonscarring alopecia of the axilla and groin with follicular papules on the trunk and extremities.
Gram-Little-Piccardi-Lassuer Syndrome
Rare variant of LP with scarring alopecia and fibrosis.
It represents the end stage of follicular fibrosis caused by a primary inflammatory dermatosis. Distinct pathologic features are absent.
Pseudopelade of Brocq
Most common form of oral LP?
Reticular
What is the most common location of erosive/ulcerative LP?
tongue
Most common sites of oral LP?
Buccal mucosa > tongue and gingiva
Most common site of genital LP?
Male genitalia are involved in 25% (MC site: glans penis)
Effector cell of LP?
CD8 T cell
Most specific marker for LP that is part of genetic/epigenetic regulation?
CXCL-9
This inflammatory mediator plays a central role in LP and is fundamentally involved in upregulating cell adhesion molecules and migration of lymphocytes to the DEJ.
IFN-g
Loss of PPAR-g (which inhibits CXCL 10,11) in LP results to?
Scarring alopecia
Agents inducing LP and lichenoid drug eruptions?
“BAD PIG”
Diseases commonly associated with lichen planus?
Laboratory tests to consider for LP?
Most cutaneous LP resolves within _____ and may be associated with relapses.
1-2 years
Recurrence of LP is found in _____% of cases (more common in generalized cutaneous disease).
20
Malignant transformation of oral LP to SCC is _____ and is linked to _____. Most common site is the _____. Risk factors include (4):
low
HPV16
tongue
long-standing disease
erosive or atrophic types
tobacco use
esophageal involvement
Skin-directed therapy for cutaneous LP?
Topical corticosteroids
Topical Calcineurin Inhibitors
Intralesional corticosteroids
Phototherapy
IL steroids are effective against these two LP types.
Resistant and hypertrophic LP
Systemic therapy for cutaneous LP?
Systemic corticosteroids
Sulfasalazine
Metronidazole
Acitretin
Antimalarials
Methotrexate
Mycophenolate mofetil
Azathioprine
Cyclosporine
Acitretin is effective against this type of LP.
Hypertrophic LP
Systemic drug effective for actinic LP.
Antimalarials
Systemic drug effective for hypertrophic LP and LPP.
Methotrexate
Systemic drug effective for refractory cutaneous LP.
Mycophenolate mofetil
Cornerstone of treatment of oral LP
Good oral hygiene (regular professional dental cleanings)
Skin-directed therapy for oral LP?
Topical corticosteroids
Topical Calcineurin Inhibitors
Intralesional corticosteroids
Retinoids
Oral corticosteroids
Oral retinoids
Antimalarials - Hydroxycholorquine
Methotrexate
Mycophenolate mofetil
Cyclosporine
Other therapies
Therapy for lichen planopilaris?
Skin-directed: High potency steroids
Systemic: Hydroxychloroquine
Therapy for frontal fibrosing alopecia?
Skin-directed: intralesional high potency steroids (topical is uneffective)
Systemic: Oral 5α-reductase inhibitors, Hydroxychloroquine
Therapy for nail LP?
Ultrapotent topical and intralesional corticosteroids
