Acrosyringeal lichen planus.

Six patients with lichen planus or lichenoid toxicodermia are described. A dermal lymphocytic infiltrate in juxtaposition to the acrosyringium and liquefaction degeneration of the acrosyringeal basal cell layer were prominent findings. Three patients had no medication. In two there was an association with beta-adrenoceptor blocking drugs. The term acrosyringeal lichen planus is proposed for this histological picture and some explanations for its pathogenesis are suggested.