Lichen planus

Question 1

What is lichen planus?

Answer 1

A pruritic inflammatory dermatosis that is commonly associated with mucosal involvement and rarely with nail dystrophy and scarring alopecia

Question 2

Where do lichen planus lesion most commonly erupt?

Answer 2

Flexor aspects of the wrist, forearms, ankles and legs

Question 3

What are features of lichen panus lesions?

Answer 3

5 P’s

• Purple
• Pruritic
• Poly-angular
• Planar
• Papular
• Wickman’s Striae

Question 4

What are wickham’s striae?

Answer 4

There may be a fine lacy white pattern on the surface of lesions

Question 5

What is common after resolution of lichen planus lesions?

Answer 5

Hyperpigmentation - especially in pigmented skin

Question 6

If someone had lichen planus on an external surface (e.g. volar aspect of wrist), where else might you look for lesions?

Answer 6

Can present as wickham’s striae

• In the mouth
• Genitals

Question 7

What is the prominent symtpom in mucosal lichen planus?

Answer 7

Severe pain

Question 8

How would you manage lichen planus?

Answer 8

• Potent topical steroids
• Oral prednisolone - if severe

Question 9

Where do lichen planus lesions often arise?

Answer 9

Sites of trauma - Kobner phenomena

Question 10

What is the pathology of lichen planus?

Answer 10

Hyperkeratosis with thickening of the granular cell layer is seen in the epidermis. A dense T cell infiltrate is seen at the dermoepidermal junction, which becomes ragged and saw-toothed. The basal layer shows liquefactive degeneration with colloid (apoptotic) bodies in the upper dermis.