Lichen planus

Question 1

Common pruritic inflammatory disease of the skin mucous membranes and hair follicles
All races
Affects 0.3% of men and 0.1% of women. Oral LP affects 1.5% of men and 2.3% of women.

Answer 1

LP

Question 2

HLA related

Answer 2

HLA DR/DQ, HLA A3

MTGFR

Question 3

Childhood LP typically accounts how many percent of LP

Answer 3

5%

Question 4

Primary skin lesions of LP are characteristic and almost pathognomonic which are

Answer 4

small flat topped polygonal papules. color is erythematous initially. well developed lesions are violaceous and resolving lesions are hyperpigmented
Specially in patients with darker skin. The surface is glistening and dry with scant adherent scales. on surface, gray or white puncta or streaks (wickham striae)

Question 5

How can white puncta or streaks (wickham striae) be seen clearly?

Answer 5

dermoscopy

Question 6

Predilection

Answer 6

flexor wrists; trunk, medial thighs, shins, dorsal hands, glans penis.

Question 7

Neil changes are present in how many percent of patients

Answer 7

5-10%

fingernails more often affected than toe nails.

Question 8

Pterygium formation is a characteristic of LP of nails. Seen in how many % of pxs?

Answer 8

20%

Question 9

Vulval LP 3 main forms

Answer 9

classic type - polygonal papules resembling cutaenous LP. affects clitoral hood and labia minora. Pruritus. 20% of vulval lp have erosive or ulcerative lp.

Vulvovaginal-gingival syndrome- involvement of these 3 sites.

third type, least common bvulval lp/ hypertrophic type. involved perineum and perianal skin. severe pruritus.

Question 10

Most common otic complaints and complications

Answer 10

Hearing loss and external auditory canal stenosis

Question 11

Pathogenesis.

Answer 11

TH1 immunologic reaction mediated by CD8 T cells. these cells induce kerstinocytes to undergo apoptosis.

Question 12

Histo

Answer 12

Sawtooth pattern of epidermal hyperplasia
orthokeratosis
beaded hypergranulosis
basal cells lost so desc as squamatized.
in superficial dermis, there is a dense band like infiltrate comp of lymphocytes and melanophages”civatte bodies” Represent necrotic keratinocytes in the superficial dermis.

hypertrophic lp/ marked epidermal hyperplasia.

Question 13

LP DIF

Answer 13

IgM

Question 14

tx

Answer 14

There is no high-quality evidence for treatment of LP of the skin scalp and mucosa. Limited locations may be ltreated with super potent topical steroids or il steroid injections.
Top tacrolimus or pimecrolimus.
phototx.
retinoid tx may be combined w phtotx in refractory cases.
hydrocychloroquiine in std doses can be effective for cutaneous oral genital and follicular lp.
thalidomide 50-150mg per day can imp refractory oral and cutaneous lp.
griseofulvin- cutaneous lo