Purple nails can be caused by trauma, Raynaud’s syndrome, pulmonary heart disease and other diseases, and should be analyzed according to the symptoms. 1. Trauma: If the patient’s nails have experienced trauma such as impact or pinch, it will lead to bruising of the patient’s nails, which will lead to the phenomenon of the patient’s nails turning purple. 2. Raynaud’s syndrome: the color of the fingers becomes white during the attack, followed by cyanosis, often starting from the fingertips, later spreading to the whole fingers, and even the palm of the hand. Accompanied by local coldness, numbness, pins and needles pain or other abnormal sensations. 3. Pulmonary heart disease: patients with pulmonary heart disease will have symptoms such as dyspnea, chest pain, fainting and cyanosis. When patients have symptoms of dyspnea, it can lead to oxygen deprivation, which can also lead to the manifestation of purple nails. There may be other reasons for the purple nails, so it is recommended to consult a doctor and follow the doctor’s instructions to standardize the treatment.