Isolated lichen planus of the nails treated with etretinate.

A 46-year-old Japanese man with isolated lichen planus of the nails is reported. The affected nails were all of the fingernails and the third and fourth toenails of both feet. Histologically, the ventral part of the proximal nail folds showed mild band-like cell infiltration below the epidermis, and the nail beds (ventral matrix) showed hypergranulosis and epidermal-dermal interphase activity with liquefaction degeneration of basal cells and a band-like cell infiltration consisting of lymphoid cells and histiocytes. Systemic use of etretinate in combination with application of steroid lotion was evaluated as very effective. Although the use of retinoids for lichen planus of the nails remains only a suggested method of treatment, a positive trial should be attempted, since this disorder sometimes results in severe nail damage.