Twenty-nail dystrophy, characterized by nail roughness, can be idiopathic or associated
with alopecia areata and less often with lichen planus. It is a benign condition that never
causes nail scarring. The nail changes usually regress spontaneously in a few years.
Reassuring the patient is probably the best approach to this nail disorder. Although
topical PUVA can be effective, continuous treatment is required to maintain the results.