Lichen Planus / Lichenoid Reaction

Question 1

What % of population does lichen planus affect?

Answer 1

2%

Question 2

What are the clinical patterns of LP/LR?

Answer 2

Reticular 
Papular
Plaque
Atrophic 
Erosive
Bullous

Question 3

LP/LR rarely affects

Answer 3

Floor of mouth
Edentulous alveolar mucosa
Palate

Question 4

LP/LR usually found

Answer 4

Buccal mucosa
Lateral tongue
Dorsum of tongue
Attached gingiva

Question 5

E/O sites affected by LP include

Answer 5

Skin - flexor aspect of wrist, forearms, ankles, torso
Genitalia
Nails and hair
Rare sites: ear, conjunctiva, oesophagus

Question 6

Histopathology of LP/LR

Answer 6

Epithelium may be hyperkeratotic, hyperplastic, erosive or ulcerated
Basal cell layer may exhibit liquefaction degeneration- Civatte bodies
Band like infiltrate of T-lymphocytes hugging the interface

Question 7

Pathogenesis of LP/LR

Answer 7

Something alters the protein signature on the basal keratinocyte
Langerhan cells detect the new antigen
Antigen is presented to T-Cells
Cell mediated immunity develops
T-cells travel to altered epithelium and kill the nasal cells
Epithelium reacts by proliferating

Question 8

Diagnosis of LP/LR

Answer 8

History and clinical exam
Biopsy not always required
Patch testing

Question 9

Treatment of LP/LR

Answer 9

Try and remove or exclude trigger
No active treatment if no active symptoms. Review and observation 
Topical steroid mouthwashes
Intralesional steroids
Systemic steroids