A novel nonsurgical treatment for pincer nail that involves mechanical force control.

We hypothesize that nails have an automatic curvature feature and that their flat shape is maintained by the daily upward mechanical forces from the finger/toe pad. Thus, nail deformities, such as pincer nail, spoon nail, and koilonychias, may be caused by an imbalance between these forces and can be treated by controlling these forces. Here, we report the case of a 55-year-old man whose severe pincer nail was effectively treated by thinning the nail, which reduced the automatic curvature force. This is the first report to show that pincer nail can be treated by a nonsurgical method that reduces the automatic curvature force, thus obviating the need for surgery. This supports the notion that mechanical stimulus-based treatments have high therapeutic potential for nail deformities.