Frequent bruises and purple patches on the body may be caused by trauma, allergic purpura, leukemia and other diseases. 1. Trauma: When the body is injured by external forces, bruises and bruises will appear. If you are often injured, it will lead to frequent bruises and purple patches on your body. 2. Anaphylactic purpura: Anaphylactic purpura is an allergic inflammation of small blood vessels throughout the body, and patients will have symptoms such as skin purpura, arthritis, abdominal pain, etc. The cause of the disease is related to infections, medicines, heredity and other factors. If long-term exposure to disease-causing factors leads to recurrent attacks, there will be frequent bruises on the body. 3. Leukemia: frequent bruising and purple body may also be caused by leukemia, leukemia patients will appear anemia, bleeding, infection and other symptoms, the cause of viral infections, immune function abnormalities, physical factors and so on. For patients with frequent bruises and purple patches on their bodies, they should consult a doctor for a clear diagnosis.