Subcutaneous hemorrhagic spots are common in “purpura”, and the causes of this symptom include trauma, allergy, and blood clotting disorders. 1. Trauma: patients may have subcutaneous hemorrhagic spots due to recent collision, hard object strikes, etc. 2. 2. Allergy: If patients are unintentionally exposed to certain allergenic substances (drugs, food, pollen, dust, insect bites, cold stimuli, etc.), vasculitis reaction occurs, resulting in increased capillary fragility and permeability, which also causes bleeding spots on the skin and mucous membranes, and in severe cases, joint swelling and pain, abdominal pain, blood in the stool, hematuria, and other symptoms, i.e., purpura allergica. 3. Coagulation dysfunction: blood coagulation disorder caused by abnormal blood vessel wall, lack of coagulation factors, thrombocytopenia, drug factors, etc. will also show various bleeding phenomena, such as nosebleed, bleeding gums, subcutaneous hemorrhagic spots, excessive menstrual flow, etc.; in severe cases, even visceral bleeding, shock and other manifestations. Patients need to consult the doctor in time, check the coagulation function and so on under the guidance of professional doctors, clarify the cause of the disease, and then carry out targeted treatment.