Clinical features

Characterized by intensely itchy shiny red or purple flat-topped papules on the skin.

A more detailed description of the classical features of lichen planus lesions is presented below (1):

• flat-topped
• shiny
• violaceous (pink/mauve/purple - the colour of the violaceae family of plants)
• polygonal
• fine, white lines forming a lace-like pattern on the surface - Wickham's striae

Other features:

• typically they are seen on the inner aspects of the elbows, on the wrists, shins and sacral area
• there may also be asymptomatic lesions on the inside of the mouth or on the genitalia
• rarely the scalp is involved - can be affected in 2 main ways:
  • cicatricial alopecia
  • lichen planopilaris (follicular lichen planus) - red spiny papules can be seen around a cluster of hairs (1)
• may be intense residual pigmentation after lesions resolve

Reference:

• 1. Primary Care Dermatology Society. Lichen planus
• 2. Dermatology in Practice (2004); 12 (2): 25-6.