Onychodystrophy

Any morphologic deformity or structural abnormality of the fingernails or toenails, including altered nail plate growth, thickness, contour, or integrity. Possible causes are physical trauma, fungal infection (onychomycosis), psoriasis, eczema, systemic organ failure (liver, kidneys, lungs, heart, thyroid disorders), medications (chemotherapy), nutritional deficiency (iron, zinc, or biotin), foot anomalies (hammertoes), congenital deformity, and aging.