Lichen Planus Overview

Question 1

How prevalent is lichen planus?

Answer 1

Present in around 1% of population

-> Of those with skin lesions- 50% also have oral lesions
-> Of those with oral lesions- 10-30% have skin lesions

Question 2

When does lichen planus tend to occur?

Answer 2

Between 30-50

Question 3

What pattern does Lichen planus follow?

Answer 3

Intermittent- periods of activity and quiescence

Question 4

How does reticular LP appear?

Answer 4

Lacey white pattern across mucosa
-> mucosa itself can be normal or erythematous (atrophy of mucosa)

Question 5

How does atrophic LP appear?

Answer 5

Mucosa is erythematous all over

Question 6

How does erosive/ulcerative LP appear?

Answer 6

No mucosa present at all
-> Yellow fibrinous covering over connective tissue seen (may be no discomfort, fibrinous covering may mitigate symptoms)

Remember- Treat symptoms not appearance

Question 7

What are the features of LP histologically?

Answer 7

T cell infiltrate into the basement membrane of connective tissue
-> Appears as lymphocytic band hugging BM (key diagnostic feature)

Civette bodies

Dead keratinocytes

Saw tooth rete ridges

Basal cell damage

Patchy acanthosis

Parakeratosis/orthokeratosis

Question 8

What causes lymphocytes to react causing LP?

Answer 8

Lymphocyte activation due to perceived threat
 Langerhans cells in epithelium present an antigen which activates immune response
 Changes in epithelium reflect attempt of immune response to remove chronic irritation
 Does not have a single cause, but is final common pathway after many things have presented to Langerhans cells and then T lymphocytes

Question 9

What are the causes of LP?

Answer 9

Genetic predisposition- not HLA linked

Physical and emotional stress

Injury to the skin- scratches or after surgery
-> isomorphic response (koebnerisation)

Localised skin disease such as herpes zoster—isotopic response

Systemic viral infection- hepatitis C

Contact allergy- metal fillings

Drugs-gold, quinine, b-blockers, ace inhibitors
-> lichenoid rash

Question 10

What are the roles of hep C and herpes in relation to lichen planus?

Answer 10

Not a cause but can be responsible for immune up regulation which can be involved in LP
-> Hep c may cause modification of self-antigens on the surface of basal keratinocytes

Question 11

What are the features of cutaneous LP?

Answer 11

 Can be seen as raised purple lesions on wrist (may have white lines- Wickham’s striae)
 Can be intensely itchy
 Scalp- are of hair loss (concerning to patient)
 Ridging on nails

Question 12

How does Oral LP present?

Answer 12

 Often no symptoms- incidental finding
 Thinning of epithelium due to atrophy can result in sensitivity/burning sensation

Question 13

What are the sites for LP in oral cavity?

Answer 13

Buccal mucosa

Gingivae (Desquamative Gingivitis)

Tongue – lateral aspect, dorsum

Lips

Palate

Question 14

What is the most common site for LP in oral cavity?

Answer 14

Buccal mucosa- can be anywhere on it
-> easy biopsy

Question 15

Why may desquamative gingivitis be a misleading term?

Answer 15

This term may also be used to describe conditions with similar clinical appearance
-> gingival pemphigoid and plasma cell gingivitis

-> Histology is required to distinguish

Question 16

What type of LP occurs on gingivae?

Answer 16

Atrophic type- erythamtous appearance
-> can be patchy
-> areas of reticular may also be seen

Question 17

Why may patients require reassurance about gingival LP?

Answer 17

Patient may be worried about gum disease and tooth loss
-> reassure patient that this is a disease of the skin covering over the gum and not to do with bone/surrounding structures

Question 18

Why must patients with gingival LP be encouraged to practice good OH? What can be done to help?

Answer 18

If poor OH, lichen planus on gingivae can be worse
-> ensure high level interdental plaque control- brushes and floss
-> involve hygienist

Question 19

How can gingival LP be distinguished from gingivitis?

Answer 19

In LP there is no excess swelling at gingival margin like gingivitis and erythema is present higher up onto attached gingivae

Question 20

Why is biopsying gingival LP considered difficult?

Answer 20

Difficult not to damage tissue when removing from periosteum (must be careful with junctional tissue when supporting tooth)
-> only do if clear between lesion and gum margin and high in sulcus

Question 21

How does amalgam related LP appear?

Answer 21

Contact point in centre, then white lines representing lichenoid reaction radiating from that patch

Question 22

What are the causes of different types of tongue LP?

Answer 22

Dorsum- idiopathic

Lateral- drug/amalgam

Question 23

What are the causes of different types of tongue LP?

Answer 23

Dorsum- idiopathic

Lateral- drug/amalgam (if isolated)

Question 24

How does LP on tongue appear?

Answer 24

Dorsum- Smoothed surface due to loss of papillae

 Can get reticular with areas of ulcerative
 Can present as hyperkeratosis- biopsy to check that it is not

Question 25

What can be done to check if amalgam is causing LP on lateral aspect of tongue?

Answer 25

Look at tongue position at REST to see if there is amalgam contact

Question 26

What is the issue with biopsying tongue?

Answer 26

Pain on healing -> if also present on buccal mucosa, choose to biopsy there instead

Question 27

What are the features of lip LP?

Answer 27

 Difficult to manage  Can be reticular or erythematous/crusty  Patients may be concerned as it is visible

Question 28

What can be done to help treat lip LP?

Answer 28

 Biopsy if unsure as it can be dysplasia  Use sunblock and topical medicaments to treat