has part has part characteristic of has modifier Abnormal nail morphology Nail dystrophy Onychodystrophy is a widely used, yet rarely defined term. Onychodystrophy can be caused by congenital nail diseases, systemic disorders, fungal and nonfungal infections, various noninfectious inflammatory dermatologic diseases of the nail unit and tumors. Onychodystrophy can also occur secondarily to systemic drug use. abnormal dystrophic nail