Papulosquamous Diseases: Lichen Planus

Question 1

Lichen Planus.

Clinical Feature SMP. morphology. common sites

Answer 1

• acute or chronic inflammation of mucous membranes or skin
• morphology: pruritic, well-demarcated, violaceous, polygonal, flat-topped papules
• common sites: wrists, ankles, mucous membranes in 60% (mouth, vulva, glans), nails, scalp

Question 2

Lichen Planus. Distribution

Answer 2

symmetrical and bilateral

Question 3

Lichen Planus.

Wickham’s striae:

Answer 3

reticulate white-grey lines over surface; pathognomonic but may not be present

Question 4

Lichen Planus

mucous membrane lesions:

Answer 4

lacy, whitish reticular network, milky-white plaques/papules; increased risk
of SCC in erosions and ulcers

Question 5

Lichen Planus nails:

Answer 5

longitudinal ridging; dystrophic; pterygium formation

Question 6

Lichen Planus scalp:

Answer 6

scarring alopecia with perifollicular hyperkeratosis and erythema

Question 7

Lichen Planus. Course

Answer 7

spontaneously resolves but may last for wk, mo or yr (mouth and skin lesions)

Question 8

Lichen Planus associated with|

Answer 8

hepatitis C

Question 9

Lichen Planus Any particular phenomenon?

Answer 9

Koebner phenomenon

Question 10

Lichen Planus

Pathophysiology

Answer 10

• autoimmune, antigen unknown

* lymphocyte activation leads to keratinocyte apoptosis

Question 11

Lichen Planus

Epidemiology

Answer 11

• 1%, 30-60 yr, F>M

Question 12

Lichen Planus

Investigations

Answer 12

• consider a skin biopsy

* hepatitis C serology if patient has risk factors

Question 13

Lichen Planus

Management. Topical, intralesional. Oral. Others

Answer 13

• short courses of oral prednisone (rarely)
• phototherapy or oral retinoids or systemic immunosuppressants (e.g. azathioprine, methotrexate,
cyclosporine) for extensive or recalcitrant cases