There are two main reasons for purple toenails. Firstly, the toenails are purple due to vasoconstriction when the toes are in a colder environment, which is of course a common physiological condition. If cold weather changes are ruled out, it usually suggests that the toenails may be damaged or have abnormal peripheral blood circulation and vascular conditions. A normal toenail should have a shiny, light pink, thin and even appearance. If you have purple toenails, it is recommended that you go to the hospital for examination and treatment to avoid serious illness and delay in treatment. It may be considered as a sign of the following conditions: 1, under the nail bruising: because the toenail has recently suffered trauma, extrusion, or recently worn tighter shoes caused under the nail capillary bleeding, and then bruising, through the toenail performance of purple. If the area of bruising is small, you can take observation, if accompanied by pain or accompanied by symptoms of infection, please seek medical attention promptly; 2, fungal infection: fungal infection may cause onychomycosis, that is, toenail lesions caused by dermatophytes invading the nail bed, which may cause toenail discoloration, usually manifested as purple-gray or gray; 3, peripheral blood circulation disorders: if the venous reflux of both lower limbs or the arteries of both lower limbs run abnormally, peripheral Blood circulation is blocked, which may lead to purple toenails; 4, congenital diseases: patients suffering from congenital heart disease, pulmonary heart disease and other diseases due to insufficient peripheral blood and oxygen supply, usually appear toe nails are purple and dark. In patients with Raynaud’s disease, the skin of the extremities and toenails will change from pale to purple and then to flushed after cold or emotional stress; 5, nail flat moss: unexplained toenail deformation, thinning or purple, pain after external pressure, if necessary, tissue biopsy to confirm the diagnosis; 6, nail hemangioblastoma: mostly occurs in the root of the nail, causing partial deformation of the toenail, manifested as purple under the nail, with pressure and pain It requires surgical treatment.