Lichen planus

Lichen planus is a skin disorder of unknown aetiology, most probably being immune-mediated.

Features

• itchy, papular rash most common on the palms, soles, genitalia and flexor surfaces of arms
• rash often polygonal in shape, with a 'white-lines' pattern on the surface (Wickham's striae)
• Koebner phenomenon may be seen (new skin lesions appearing at the site of trauma)
• oral involvement in around 50% of patients: typically a white-lace pattern on the buccal mucosa
• nails: thinning of nail plate, longitudinal ridging

Lichenoid drug eruptions - causes:

• gold
• quinine
• thiazides

Management

• potent topical steroids are the mainstay of treatment
• benzydamine mouthwash or spray is recommended for oral lichen planus