Understanding Blood Blisters: Causes, Care, and Prevention
A blood blister can startle anyone—a dark red or purplish bubble beneath the skin that seems to appear out of nowhere. While they are usually harmless, blood blisters can cause discomfort and, occasionally, signal an underlying issue. Knowing how they form and how to care for them can help you manage them safely and recognize when to seek medical attention.
What Is a Blood Blister?
Blood blisters form when tiny blood vessels (capillaries) under the skin break, while the outer layer of skin remains intact. The leaked blood collects beneath the skin, creating a raised, fluid-filled spot. Unlike a clear blister, blood blisters appear red, maroon, or purple.
Common locations include:
Fingers and palms
Toes and soles
Inside the mouth (cheeks, tongue, or gums)
Common Causes
Most blood blisters develop from sudden pressure or repeated friction, such as:
Slamming a finger in a door
Wearing tight or poorly fitting shoes
Using tools or sports equipment without protection
Repetitive movements that press on the skin
Oral blood blisters often result from:
Accidental biting
Dental procedures
Sharp or ill-fitting dental appliances
Some people may be more prone to blood blisters due to:
Thin or fragile skin
Circulation issues
Diabetes
Blood or clotting disorders
Symptoms to Expect
Blood blisters usually present as:
A raised, bubble-like area under the skin
Dark red, purple, or black coloring
Tenderness or pressure pain
Occasional swelling around the area
Most heal on their own within one to two weeks and do not require medical treatment.
Should You Pop a Blood Blister?
Avoid popping blood blisters. The skin covering the blister acts as a natural barrier against infection. Popping it can introduce bacteria and delay healing.
If a blister bursts naturally:
Clean the area gently with soap and water
Apply an antiseptic
Cover with a sterile bandage
Keep it clean and dry
How to Treat a Blood Blister at Home
For uncomplicated blisters:
Reduce pressure or friction on the area
Apply a cold compress for 10–15 minutes to reduce swelling
Keep the blister clean and protected
Wear properly fitting shoes or gloves if needed
Avoid harsh chemicals or home remedies that can irritate the skin
Blood Blisters in the Mouth
Oral blood blisters often heal quickly but can be painful. To manage them:
Rinse with warm salt water to reduce irritation
Avoid hot, spicy, or sharp foods until healed
Frequent or unexplained oral blisters should be checked by a dentist or doctor.
When to See a Doctor
Seek medical attention if:
The blister is extremely painful or enlarging
You notice signs of infection (redness, warmth, pus, fever)
Blisters appear repeatedly without injury
You have diabetes, poor circulation, or a bleeding disorder
Healing takes longer than two weeks
Rarely, recurring or unexplained blood blisters may signal a serious underlying condition that requires evaluation.
Can Blood Blisters Be Prevented?
You can lower your risk by:
Wearing well-fitting shoes and protective gloves
Cushioning tools or sports equipment
Keeping skin moisturized to prevent cracks
Managing underlying health conditions
Final Thoughts
Blood blisters are usually minor injuries caused by pressure or friction. Most heal on their own and do not pose a serious threat.
However, pay attention to their location, frequency, and severity. If blisters recur or take longer to heal, consult a healthcare professional. Early evaluation can prevent complications and help identify hidden health issues.
