Lichen Planus Overview Flashcards
How prevalent is lichen planus?
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
When does lichen planus tend to occur?
Between 30-50
What pattern does Lichen planus follow?
Intermittent- periods of activity and quiescence
How does reticular LP appear?
Lacey white pattern across mucosa
-> mucosa itself can be normal or erythematous (atrophy of mucosa)
How does atrophic LP appear?
Mucosa is erythematous all over
How does erosive/ulcerative LP appear?
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
What are the features of LP histologically?
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
What causes lymphocytes to react causing LP?
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
What are the causes of LP?
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
What are the roles of hep C and herpes in relation to lichen planus?
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
What are the features of cutaneous LP?
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
How does Oral LP present?
Often no symptoms- incidental finding
Thinning of epithelium due to atrophy can result in sensitivity/burning sensation
What are the sites for LP in oral cavity?
Buccal mucosa
Gingivae (Desquamative Gingivitis)
Tongue – lateral aspect, dorsum
Lips
Palate
What is the most common site for LP in oral cavity?
Buccal mucosa- can be anywhere on it
-> easy biopsy
Why may desquamative gingivitis be a misleading term?
This term may also be used to describe conditions with similar clinical appearance
-> gingival pemphigoid and plasma cell gingivitis
-> Histology is required to distinguish
What type of LP occurs on gingivae?
Atrophic type- erythamtous appearance
-> can be patchy
-> areas of reticular may also be seen
Why may patients require reassurance about gingival LP?
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
Why must patients with gingival LP be encouraged to practice good OH? What can be done to help?
If poor OH, lichen planus on gingivae can be worse
-> ensure high level interdental plaque control- brushes and floss
-> involve hygienist
How can gingival LP be distinguished from gingivitis?
In LP there is no excess swelling at gingival margin like gingivitis and erythema is present higher up onto attached gingivae
Why is biopsying gingival LP considered difficult?
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
How does amalgam related LP appear?
Contact point in centre, then white lines representing lichenoid reaction radiating from that patch
What are the causes of different types of tongue LP?
Dorsum- idiopathic
Lateral- drug/amalgam
What are the causes of different types of tongue LP?
Dorsum- idiopathic
Lateral- drug/amalgam (if isolated)
How does LP on tongue appear?
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
What can be done to check if amalgam is causing LP on lateral aspect of tongue?
Look at tongue position at REST to see if there is amalgam contact
What is the issue with biopsying tongue?
Pain on healing
-> if also present on buccal mucosa, choose to biopsy there instead
What are the features of lip LP?
Difficult to manage
Can be reticular or erythematous/crusty
Patients may be concerned as it is visible
What can be done to help treat lip LP?
Biopsy if unsure as it can be dysplasia
Use sunblock and topical medicaments to treat
