Lichen Planus

Question 1

definition of lichen planus

Answer 1

immune mediated condition of unknown aetiology affecting the skin and/ or mucosa

Question 2

discuss the epidemiology of lichen planus

Answer 2

relatively common disease affecting 0.5-2% of the general population
females affected more than males
most common in adults >40

Question 3

the pathogenesis of lichen planus is not fully understood, what is thought to occur?

Answer 3

cell mediated immune response to antigen or antigenic changes within epithelial cells resulting in a type IV hypersensitivity reaction
Inflammatory infiltrate is dominated by CD8+ cytotoxic T lymphocytes

Question 4

what does lichen planus affecting the gingiva commonly present as

Answer 4

desquamative gingivitis

Question 5

what are the typical intra oral characteristics of lichen planus

Answer 5

can present in various forms but most commonly sees buccal mucosa affected and majority are bilateral with some being symmetrical

Question 6

reticular lichen planus

Answer 6

white lesions in a lacy or web like pattern (wickhams striae), often on a mildly erythmatous background

Question 7

plaque like lichen planus

Answer 7

white plaques, most often seen on dorsum of tongue

Question 8

papular lichen planus

Answer 8

small white papules, can occur concurrently with reticular

Question 9

atrophic lichen planus

Answer 9

strong erythmatous change where mucosa has thinned
often combined with poorly defined striae

Question 10

erosive/ ulcerative lichen planus

Answer 10

extreme atrophy, can lead to ulceration, may be smooth yellowish layer of fibrin covering lesion

Question 11

what may be seen histologically in white lichen planus lesions

Answer 11

hyperparakeratosis or hyperorthokeratosis

Question 12

what may be seen histologically in atrophic lichen planus lesions

Answer 12

severe thinning or flattening of epithelium

Question 13

what is the characteristic histological sign of lichen planus

Answer 13

dense, well defined sub epithelial band of inflammatory cell infiltrate consisting mainly of T cells

Question 14

what occurs histologically in lichen planus

Answer 14

dense infiltrate of lymphocytes subepithelialy
lymphocytes cross basement membrane into epithelium and are associated with apoptosis of basal cells
Degenerating basal cells are termed Civatte bodies and appear shrunken and condensed

Question 15

civatte bodies

Answer 15

apoptic keratinocytes
seen histologically in lichen planus

Question 16

discuss the extra oral presentation of lichen planus

Answer 16

most common skin presentation is raised purple lesions around wrists
lesions are often itchy
white wicking pattern may be seen similar to OLP reticular form
may also present on genitals

Question 17

what should be considered if palatal ‘lichen planus’ lesions are found

Answer 17

lupus erythmatosis

Question 18

what 2 diseases present similarly to lichen planus in the mouth

Answer 18

lupus erythmatosis
GVHD

Question 19

how can oral lichenoid lesions and oral lichen planus be told apart

Answer 19

histologically indistinguishable
Atypical distribution is indicative of lichenoid reaction e.g unilateral , non symmetrical
Very hard to tell apart

Question 20

what is an oral lichenoid lesion

Answer 20

a lesion within mouth which develops in response to some dental materials and some systemic medications

Question 21

name 3 systemic medications associated with oral lichenoid lesions

Answer 21

NSAIDs
Anti hypertensives - ace inhibitors, beta blockers, diuretics
DMARDs

Question 22

malignant potential of OLP and OLR

Answer 22

dispute over actual figures , considerable variation
most conclude low risk of malignant change 1% over 10 years

Question 23

what tests should be done to aid diagnosis of lichen planus

Answer 23

blood tests - iron, vit B12 and folate screen - more symptomatic in haematinic deficiencies
Biopsy

autoantibody screen should also be done if lupus suspected

Question 24

discuss amalgam related oral lichenoid lesions

Answer 24

very close proximity between amalgam and affected mucosa
discuss either leaving (malignant potential) or replacing amalgams with composite with patient (cost and tooth destruction )

Question 25

discuss medication related oral lichenoid lesions

Answer 25

often widespread across mouth
very difficult to distinguish from LP as many patients taking causative drugs
must consider if potential benefit of stopping drug outweigh risks

Question 26

step 1 of treatment for lichen planus
- OTC remedies

Answer 26

• chlorhexidine mouthwash 2x daily
• benzydamine mouthwash as needed

Question 27

what should patients with symptomatic lichen planus avoid

Answer 27

SLS containing toothpaste - e.g kingfisher
spicy and acidic foods

Question 28

step 2 of lichen planus treatment
- topical corticosteroids (primary care)

Answer 28

• betamethasone rinse - 1mg in 10ml 2mins 2x daily
• beclomethasone MDI - 0.5mg puff, 2 puffs 2-3x daily

Question 29

step 3 of lichen planus treatment
- hospital setting

Answer 29

• topical tacrolimus (ointment or mouthwash) (immunosuppresive)
• clobetasol (‘veneer’ for gingival lesions) (steroid)
• hydroxychloroquine (DMARD)
• azathioprine (immune modulator)