What Causes Bent Fingernails?

Bent fingernails can be caused by injury, infection, medications, disease or by biting or other aggravating factors. If fingernails have growth distortion, clubbing, changing of colors or any other concerning abnormalities, seek the opinion of a heath care medical professional, recommends the National Institutes of Health's MedlinePlus. The changing conditions of fingernails can be a symptom of a more serious underlying health concern.