A blood blister is a type of blister that forms when subdermal tissues and

blood vessel The blood vessels are the components of the circulatory system that transport blood throughout the human body. These vessels transport blood cells, nutrients, and oxygen to the tissues of the body. They also take waste and carbon dioxide away ...

s are damaged without piercing the

skin Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other animal coverings, such as the arthropod exoskeleton, have different de ...

. It consists of a pool of

lymph Lymph (from Latin, , meaning "water") is the fluid that flows through the lymphatic system, a system composed of lymph vessels (channels) and intervening lymph nodes whose function, like the venous system, is to return fluid from the tissues ...

, blood and other body 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. There are also blood blister-like

aneurysm An aneurysm is an outward bulging, likened to a bubble or balloon, caused by a localized, abnormal, weak spot on a blood vessel wall. Aneurysms may be a result of a hereditary condition or an acquired disease. Aneurysms can also be a nidus ( ...

s as these are known to be located in the supraclinoid internal carotid artery and have been recognized as having unique pathological and clinical features.

Causes

Blood blisters are commonly caused by accidents in which the skin is pinched by a tool, mechanism, or heavy weight without protective equipment. Blood blisters can also arise from forcible human contact, including grappling. Blood blisters also may occur with friction caused by constant rubbing of skin against a surface. Ill-fitting shoes that rub on the skin can cause the blood vessels in the skin to break and form a blood clot under the skin, resulting in a blood blister. Certain sports activities that require repeated movement and rubbing of the skin against equipment may also cause this. So baseball pitchers, rowers, and drummers often contract blood blisters on the fingers and palms. They also form as a result of

frostbite Frostbite is a skin injury that occurs when exposed to extreme low temperatures, causing the freezing of the skin or other tissues, commonly affecting the fingers, toes, nose, ears, cheeks and chin areas. Most often, frostbite occurs in the ha ...

. Blood blisters can also occur in the mouth for a variety of reasons including side effects to certain medications, nutritional deficiencies, and mouth injuries.

Treatment

There are several methods of healing blood blisters, including

elevation The elevation of a geographic location is its height above or below a fixed reference point, most commonly a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface (see Geodetic datum § Ver ...

of the wound combined with application of a cold pack, and application of padded dressings or splints.

References

{{General injuries Skin conditions resulting from physical factors

Causes

Treatment

See also

References