From the Research
The medical term for a blood blister is hematoma or, more specifically, a subepidermal hematoma. This occurs when blood vessels near the skin's surface are damaged but the skin remains intact, allowing blood to collect in a pocket between layers of skin. Unlike regular blisters that contain clear fluid, blood blisters contain blood that gives them their characteristic red or purple appearance. They commonly develop after pinching or crushing injuries to the skin, particularly on fingers, toes, and areas with thin skin.
According to a recent study 1, subcutaneous hematomas can cause increases in FDP and D-dimer levels, without activating the blood coagulation/fibrinolysis system. Blood blisters typically heal on their own within 1-2 weeks as the body reabsorbs the trapped blood. Treatment generally involves protecting the blister from further trauma by covering it with a bandage, avoiding popping it to prevent infection, and applying cold compresses initially to reduce swelling.
Some key points to consider when dealing with blood blisters include:
- They can occur after trauma or operative procedures, as noted in a study on hematomas of the lower extremity 2
- They may present with inflammatory or febrile symptoms, especially in elderly patients treated with anticoagulants or anti-platelets 3
- Prompt recognition and operative evacuation of hematomas should be performed to avoid significant complications, such as necrosis of the overlying skin 2
- If a blood blister is particularly large, painful, or in a problematic location, medical attention may be warranted, especially for people with diabetes or compromised immune systems who face higher infection risks.