Most flat fingernails are congenital abnormalities, but iron deficiency can also cause flat nails. Congenital factors cannot be treated, while pathological factors can be improved through daily life and medication. Flat nails are characterized by flattened nail plate, thinning, uneven surface, cross texture, tennis racket shape, wide and flat distal end, shortened knuckles and swollen nail grooves. Flat nails caused by congenital anomalies can not worry, should be due to genetic factors, so there is no need to do special treatment, and will not have an impact on health. Iron deficiency caused by the need to supplement iron, such as oral iron (ferrous sulfate, etc.), iron injections (for patients who are not effective in oral iron). Daily life should pay attention to adjust the diet structure, balanced diet, rich in nutrients, supplementation of trace elements, etc., will also be very good for flat nail. In addition, flat nails can also be seen in hookworm disease. If you have flat fingernails and other uncomfortable symptoms, you should consult a doctor in time.