The common causes of inexplicable bruises on the body include external factors such as trauma, accidental contact, falling, touching, smashing, extrusion and internal factors such as thrombocytopenia and increased vulnerability of blood vessels. 1. External factors: trauma, accidental contact, falling, touching, smashing, extrusion and other causes can cause bruising. Usually people have bruises when they are injured, depending on the severity of the injury. If there is squeezing or hand pinching, it will cause ecchymosis, which is caused by trauma. 2. Internal factors: If the number of platelets is abnormal, such as thrombocytopenia, the slightest contact will bleed, thus forming bruises. In addition, if there is an abnormality in the blood vessels, such as increased fragility of the blood vessels, it can lead to skin rupture, resulting in subcutaneous bleeding, which leads to bruising. Decreased platelet count and clotting disorders can lead to bruising. If you always have inexplicable bruises on your body and they persist without relief and are accompanied by other physical discomforts, it is important to seek medical attention.