Bruising of the hands may be caused by trauma, anaphylactic purpura, thrombocytopenic purpura, purpura simplex, drugs and other factors. 1. Trauma: impact, slap and other trauma may lead to subcutaneous bruising of the hand, usually accompanied by local soft tissue swelling, pain and other symptoms. 2. Anaphylactic purpura: its etiology is not clear, may be related to genetic, bacterial infection and other factors, most patients in the onset of 1 ~ 3 weeks before the onset of general malaise, low-grade fever, malaise and other symptoms, followed by the appearance of the upper limbs, lower limbs and other parts of the skin purpura, but also joint swelling and pain, abdominal pain and other symptoms. 3. Thrombocytopenic purpura: It is a group of autoimmune diseases with thrombocytopenia as the basic feature, mainly manifested as petechiae and ecchymoses of different sizes on the skin of limbs and trunk, bleeding gums, spontaneous nosebleeds, vomiting blood and black stools and other symptoms. 4. Purpura simplex: its cause is not yet completely clear, mainly manifested as recurrent petechiae and ecchymoses on the skin, mainly in the lower limbs, and also increased bleeding, prolonged bleeding time and other symptoms. 5. Drugs: If you take anti-platelet aggregation drugs or anticoagulant drugs, it may also lead to the symptoms of easy bruising of the skin, such as aspirin, warfarin, clopidogrel bisulfate tablets and other drugs. Hand bruising may also be caused by other factors, it is recommended that patients seek medical attention in a timely manner in order to clarify the cause of the disease, under the guidance of the doctor for targeted treatment.