A blood blister is a blood-filled pocket of skin that forms due to a small blood vessel close to the surface of the skin rupturing without the skin being pierced.
In addition to the pool of blood and other bodily fluids trapped underneath the skin, the other symptom of a blood blister is pain, as there is usually bruising where the blister-inducing injury occurred.
Blood blisters usually happen if the skin is somehow pinched or crushed, resulting in blood leaking into a tear between the layers of skin. The blisters can also form from friction. Common causes include the skin being pinched by a tool or other heavy piece of machinery, and forcible human contact like wrestling.
Home remedies for the treatment of blood blisters include application of an ice pack to reduce swelling and pain, elevating the wound and using a padded dressing or bandage to protect the blister until it heals. Applying aloe vera can also help the wound heal quickly.
Some doctors recommend piercing or popping the blister to drain the blood and fluid, which may relieve some of the pressure and pain. However, as sites like WebMD warn, this can cause infection, so it’s best to have a professional health care provider attempt to pop the blister in a sterile environment rather than trying to do so on your own.