Blood blister

on palm of right hand

Large blood blister on right foot

A blood blister is a type of blister that forms when subdermal tissues and blood vessels are damaged without piercing the skin. It consists of a pool of lymph, blood and other bodily fluids trapped beneath the skin. If punctured, it suppurates a dark fluid. Sometimes the fluids are cut off from the rest of the body and dry up, leaving behind dead cell material inside the blister with a texture like putty. Some blood blisters can be extremely painful due to bruising where the blister occurred.

Prevention

Common areas that suffer from blood blisters include the hands and feet.

When the cause is abrasion, moleskin can be used to prevent blood blisters from forming. Blood blisters are commonly caused by accidents in which the skin is pinched by a tool, mechanism, or heavy weight without protective gear. The only prevention in these situations is to use tools carefully and wear appropriate protective gear. Blood blisters also may occur with constant rubbing back and forth, or as a result of frostbite.

There are several methods of healing blood blisters. These include:

• For immediate care: leave the blister alone. Elevate the injured area; apply a cold pack; and when pain subsides, apply padding or a splint to protect the injured area.
• Elevating the affected anatomy and applying pressure reduces blood leakage into the damaged area, cold reduces the inflammatory response.
• Soak the blister in epsom salts to reduce swelling.
• Keep the area cleanly bandaged, and replace the bandage daily or whenever necessary.

In some cases, it is advisable to visit a doctor to ensure that the blood blister is not a symptom of a more dangerous condition.

Refrain from irritating the affected area. If necessary, apply moleskin to the blister to keep using the area, but note that it will not heal as quickly: even with a moleskin cover, the blister can worsen.

If the blister breaks, quickly rinse the area and apply an antiseptic such as neosporin or TCP. It is not recommended to break a blister because it may lead to infection.

People who are exposed to blistering but cannot interrupt their work to allow for proper treatment, such as soldiers; musicians; and sportsmen, have developed a series of approaches to treating blisters. These are inadvisable, as they are likely to slow healing or cause further damage, especially if undertaken improperly.

• Especially on long marches a blister can cause the affected person to hobble which could cause problems in joints or muscles. It is advisable to continue walking as normally as possible "through the blister". It will either pop and necessitate treatment at the next stop, or flatten out and become less painful.
• At an overnight stop a disinfected, thin cotton thread can be stitched through the blister. This provides a drain and lets the fluid come out. The dead skin from the top of the blister will then stick to the soft flesh of the underside and form a temporary protection. Great care and attention is advised with this treatment and regular inspection of the blister is necessary to recognize any symptom of infection immediately.
• Special blister pads are available. The skin of the blister must be totally removed, the wound dried and disinfected. The pad can then be stuck directly onto the wound where it will protect from further abrasion. These pads have the best results when applied to healthy skin in known blistering spots before the activity (marches etc) begins.

Small blood blisters, such as obtained when something pinches the pad of a finger, may hurt for a minute but soon subside, leaving only a painless blister. Such blisters should be left to heal naturally; there is a possibility of infection if they are punctured, and unless it is painful, the risk is likely not worth the reward.

See also

• Bleeding
• Blister
• Bruise
• Cherry hemangioma