lichen

Question 1

What is the primary lesion in lichen planus?

Answer 1

Papules.

Question 2

What symptom is commonly associated with lichen planus?

Answer 2

Severe itching.

Question 3

What is the prevalence of lichen planus?

Answer 3

Less than 1%.

Question 4

What age group is commonly affected by lichen planus?

Answer 4

30–70 years.

Question 5

What is the gender ratio for lichen planus prevalence?

Answer 5

Female to male ratio is 3:1 or 3:2.

Question 6

What causes basal layer keratinocyte apoptosis in lichen planus?

Answer 6

Cytotoxic T-cell reaction.

Question 7

What immune mechanism is responsible for lichen planus?

Answer 7

Immune-mediated T-cell cytotoxicity against keratinocytes.

Question 8

What diseases are associated with lichen planus?

Answer 8

Dermatomyositis, alopecia areata, IBD, autoimmune thyroiditis, HBV, HCV, primary biliary cirrhosis.

Question 9

How do primary lesions of lichen planus appear?

Answer 9

Shiny, flat-topped, polygonal papules and plaques.

Question 10

What are Wickham striae?

Answer 10

Fine white lines on the surface of papules in lichen planus.

Question 11

What gives rise to Wickham striae?

Answer 11

Increased granular cell layer reflecting incident light.

Question 12

What color are new lesions of lichen planus?

Answer 12

Purple or violet.

Question 13

What happens to lesions in the regressive phase of lichen planus?

Answer 13

They become dark brown and may persist for years.

Question 14

What are histological features of lichen planus?

Answer 14

Orthokeratotic hyperkeratosis, hypergranulosis, band-like infiltrate in dermis.

Question 15

Where are lichen planus lesions commonly located?

Answer 15

Flexural wrists, forearms, lower limbs, lumbar regions, nails, scalp, mouth, and genitalia.

Question 16

What are features of oral lichen planus?

Answer 16

White striations, lacy network, white papules and plaques, erythema, and erosions.

Question 17

Which virus is associated with erosive oral lichen planus?

Answer 17

Hepatitis C virus (HCV).

Question 18

What is the most frequent site for oral lichen planus?

Answer 18

Genal mucosa.

Question 19

What are potential complications of erosive oral lichen planus?

Answer 19

Burning, pain, and potential for malignancy.

Question 20

What are some clinical variants of lichen planus?

Answer 20

Follicular, verrucous, vesico-bullous, annular, linear striatus, psoriasiform.

Question 21

What causes blistering in vesico-bullous lichen planus?

Answer 21

Detachment between the basal layer and dermis.

Question 22

Where is annular lichen commonly found?

Answer 22

Genitalia.

Question 23

What is striatus lichen?

Answer 23

A linear variant of lichen planus.

Question 24

What are examples of lichenoid dermatoses?

Answer 24

Sclero-atrophic lichen, lichen nitidus, drug-related lichenoid reactions, contact dermatitis, GVHD, neurodermatitis.

Question 25

What drugs are associated with lichenoid reactions?

Answer 25

Hydralazine, beta-blockers.

Question 26

What causes lichenoid contact dermatitis?

Answer 26

Trichloroethylene, metals.

Question 27

What is lichen nitidus?

Answer 27

Tiny whitish papules grouped but not confluent.

Question 28

Where does lichen nitidus commonly appear?

Answer 28

Forearms, chest, abdomen, genitalia, and buttocks.

Question 29

What is graft-versus-host disease (GVHD)?

Answer 29

An immunological reaction post stem cell transplant.

Question 30

What are skin signs of acute GVHD?

Answer 30

Erythema, vesicles, and blisters.

Question 31

What are skin signs of chronic GVHD?

Answer 31

Lichenoid papules and scleroderma-like changes.

Question 32

What is sclero-atrophic lichen?

Answer 32

Whitish papules evolving into atrophic areas with erosion.

Question 33

Where is sclero-atrophic lichen commonly found?

Answer 33

Upper chest and genital area.

Question 34

What is 'figure of eight' in sclero-atrophic lichen?

Answer 34

Involvement of labial, perineal, and perianal areas with introital narrowing.

Question 35

What are late complications of sclero-atrophic lichen?

Answer 35

Cicatricial retraction and increased cancer risk.

Question 36

What autoimmune diseases are linked to sclero-atrophic lichen?

Answer 36

Thyroiditis, alopecia areata, vitiligo, anemia.

Question 37

What serum marker is found in patients with sclero-atrophic lichen after 12 months?

Answer 37

Anti-ECM1 antibodies.

Question 38

How do anti-ECM1 antibodies affect the skin?

Answer 38

They damage dermal structure by binding to metalloproteinases and fibulin.

Question 39

Why do lesions in oral lichen planus appear more visible?

Answer 39

Due to the lack of keratin and thin epithelium.

Question 40

What is the histological level of lichen papules?

Answer 40

Dermo-epidermal junction.

Question 41

What is lichenification?

Answer 41

Thickening of the skin from chronic rubbing or scratching.

Question 42

What conditions resemble lichen planus clinically?

Answer 42

Candida, squamous cell carcinoma (SCC).

Question 43

What is a differential diagnosis for oral lesions in lichen planus?

Answer 43

Candidiasis and SCC.

Question 44

Can lichen planus undergo spontaneous regression?

Answer 44

Yes, after some months.

Question 45

What is the pathogenesis of lichen planus similar to?

Answer 45

Graft-versus-host disease (GVHD).

Question 46

What causes spinulous or follicular lichen?

Answer 46

Inflammation around hair follicles.

Question 47

What is the effect of lichen planus on nails?

Answer 47

It can affect the nail matrix causing damage.

Question 48

What is the immune mechanism of damage in lichen planus?

Answer 48

Cytotoxic T-cell targeting of basal keratinocytes.

Question 49

Is lichen planus considered a potentially pre-cancerous condition?

Answer 49

Yes, especially in mucosal forms.

Question 50

What part of the skin is affected first in lichen planus?

Answer 50

The basal layer of the epidermis.