A blood blister is a small, dark pocket of blood that forms under the skin when surface capillaries are damaged, typically by pinching or friction. While often harmless and healing on their own, they can be uncomfortable. This guide explains their causes, proper care, and signs you should see a doctor.
**What Causes a Blood Blister?**
Blood blisters form when minor trauma breaks blood vessels beneath the skin, trapping the blood under an intact top layer. This creates a raised, red-to-purple bubble. Common causes include:
- **Physical trauma:** Pinching (e.g., in a door), repeated friction, or using tools without gloves.
- **Ill-fitting footwear:** Tight shoes that rub against toes or heels.
- **Oral injuries:** Accidentally biting your cheek or tongue, or irritation from dental appliances.
They occur most often on the fingers, hands, toes, feet, and inside the mouth.
**How to Care for a Blood Blister at Home**
Do not pop a blood blister, as the skin protects against infection. Instead:
1. **Protect and relieve:** Reduce pressure on the area. Apply a cold compress to ease pain and swelling.
2. **Keep it clean:** Gently wash with soap and water. If it bursts on its own, clean it, apply an antiseptic, and cover it with a sterile bandage.
3. **Let it heal:** It will typically dry out and heal within one to two weeks. For mouth blisters, rinse with warm salt water and avoid irritating foods.
**When to See a Doctor**
Most blood blisters are minor, but seek medical attention if you notice:
- Signs of infection (increasing redness, warmth, pus, or fever).
- Unusual pain or rapid growth.
- Frequent blisters with no clear cause.
- Slow healing (longer than two weeks).
- If you have diabetes, a bleeding disorder, or poor circulation.
**Prevention Tips**
You can minimize risk by:
- Wearing properly fitted shoes and protective gloves during physical tasks.
- Cushioning areas prone to friction.
- Managing underlying health conditions that may affect skin or circulation.
**Conclusion**
While usually a minor injury from pressure or friction, paying attention to a blood blister’s behavior is important. Most resolve with simple care, but recurring, persistent, or infected blisters warrant a professional evaluation to rule out underlying issues.
