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.
Any finger or toe nail concerns or abnormalities should be checked by a doctor. The doctor will examine the nails, ask about other symptoms and may run diagnostic tests, X-rays or other laboratory tests to determine the cause of fingernails growing in bent, notes MedlinePlus.