Palm bruises can be caused by trauma, poisoning, purpura or heart failure. 1. Trauma: the palm of the hand by violent impact, bumping and other physical injuries, resulting in subcutaneous injury bleeding, blood pooling, can be manifested in the palm of the blue. 2. Poisoning: some poisonings can also cause palms blue, such as acute nitrite poisoning, will lead to the patient’s normal hemoglobin loss of oxygen-carrying transport capacity, and then make the body hypoxia, skin and mucous membrane cyanosis, palms blue. 3. Allergic purpura: before the onset of the onset of upper respiratory tract infection, low fever, general malaise and other prodromal symptoms, followed by the emergence of red papules, usually within 24 hours of the development of a pinpoint to soybean-sized purpura, there can also be petechiae, some of the purpura has a tendency to merge, the appearance of palms ubiquitous green. There may also be other causes of palmar purpura, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, and then carry out targeted treatment or treatment.