Upturned nails, also known as ingrown nails, can be caused by congenital or acquired factors. Congenital factors are mainly related to heredity, while acquired factors include long-term anoxic diseases, fungal infectious diseases and trauma. 1. Innate factors: If the parents themselves have antinail phenomenon, it is very likely to be passed on to the next generation, resulting in the child also appearing antinail phenomenon. 2. Acquired factors: (1) long-term hypoxic disease: due to hypoxia will lead to peripheral circulation of blood is insufficient, causing metabolic disorders, resulting in the emergence of the phenomenon of anti-nail, may be lower oxygen content of the plateau area the incidence of some higher, commonly found in iron-deficiency anemia, chronic obstructive pulmonary disease and so on. (2) Fungal infectious diseases: If the patient’s nail plate is infected by fungus, it may cause onychomycosis, and in severe cases, nail breakage, nail upturning, nail color becoming gray and brittle, etc. (3) Trauma: If the nail area is hit or squeezed by external force, the injury to the nail matrix may lead to upturning of the nails and the formation of anti-nail phenomenon. As the causes are many, it is recommended that the patients who have anti-nail phenomenon go to the regular hospital in time for a clear diagnosis, and standardized treatment under the guidance of the doctor.