![Hematomasubungual](https://upload.wikimedia.org/wikipedia/commons/e/ed/Hematomasubungual.png)
A subungual hematoma is a collection of
blood
Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in the c ...
(
hematoma
A hematoma, also spelled haematoma, or blood suffusion is a localized bleeding outside of blood vessels, due to either disease or trauma including injury or surgery and may involve blood continuing to seep from broken capillary, capillaries. A he ...
) underneath a
toenail or fingernail. It can be extremely painful for an injury of its size, although otherwise it is not a serious medical condition.
Nature
A
laceration
A wound is a rapid onset of injury that involves lacerated or punctured skin (an ''open'' wound), or a contusion (a ''closed'' wound) from blunt force trauma or compression. In pathology, a ''wound'' is an acute injury that damages the epiderm ...
of the
nail bed causes bleeding into the constricted area underneath the hard
nail plate
A nail is a claw-like plate found at the tip of the fingers and toes on most primates. Nails correspond to the claws found in other animals. Fingernails and toenails are made of a tough protective protein called alpha-keratin, which is a polymer. ...
. The blood pools under the nail, giving a reddish, brownish, blueish, or grey/blackish discoloration. The blood puts pressure to the nailbed causing pain which can be throbbing in quality and disappears when the pressure on the nail bed is relieved.
Subungual hematomas typically heal without incident, though
infection
An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable dise ...
may occur. The pressure of the blood blister may cause separation of
nail plate
A nail is a claw-like plate found at the tip of the fingers and toes on most primates. Nails correspond to the claws found in other animals. Fingernails and toenails are made of a tough protective protein called alpha-keratin, which is a polymer. ...
from the
nail bed (
onycholysis
Onycholysis is a common medical condition characterized by the painless detachment of the nail from the nail bed, usually starting at the tip and/or sides. On the hands, it occurs particularly on the ring finger but can occur on any of the fingern ...
), but the nail should not be pulled off, as this can cause scarring of the nailbed and deformed nails.
Nail discolouration may last some months.
[
The nail plate may also become thicker and more brittle as a result of the injury ( onychochauxis). The deformed nail plate will gradually grow out and be replaced by new, normal-appearing nail plate in several months' time. Infrequently, the nail may become painful and require surgical drainage.]
Causes
The condition is caused by a traumatic injury
An injury is any physiological damage to living tissue caused by immediate physical stress. An injury can occur intentionally or unintentionally and may be caused by blunt trauma, penetrating trauma, burning, toxic exposure, asphyxiation, or o ...
, such as slamming a finger
A finger is a limb of the body and a type of digit, an organ of manipulation and sensation found in the hands of most of the Tetrapods, so also with humans and other primates. Most land vertebrates have five fingers ( Pentadactyly). Chambers ...
in a door, or from sports activities, especially those involving sudden accelerations, such as soccer, basketball, and tennis, or going downhill, such as running or hiking rugged terrain, and ill-fitting footwear.
Repeatedly thrusting the toes against a shoe's toe box
The toe box is the section of footwear that surrounds the toes on closed-toe shoes. Toe boxes that are too tight can cause injuries and foot deformities, whereas wider toe boxes may be used to treat or prevent common foot conditions such as Morto ...
can cause a subungual hematoma called jogger's toe, runner's toe, or black toenail. In a marathon, several percent of runners may be affected.[ Wearing footwear which fits helps prevent runner's toe.][
If the shoe is too loose on the midfoot, the foot can slide forwards in the shoe, especially when going downhill. This may jam the toes into the end of the toebox.][ If the foot is sliding forwards because the shoe is too loose around the midfoot, it may be restrained by lacing the shoe carefully, or placing bulky padding between the tongue and the lacing, or by wrapping a strap in a figure-eight around the foot and ankle (]image
An image is a visual representation of something. It can be two-dimensional, three-dimensional, or somehow otherwise feed into the visual system to convey information. An image can be an artifact, such as a photograph or other two-dimensiona ...
). Excessively tight or uneven fit around the midfoot may, however, cause tendon problems.
Separately, if there is not enough space around the toes, the toes will also hit the toebox repeatedly.[ Feet become longer and wider when weight is put on them, because the arches flatten, and the toes also splay and bend.][ (this is the publication of a four-year review into the footwear of the US military by the Army Shoe Board, of which the author, a physician and senior officer of the ]United States Army Medical Corps
The Medical Corps (MC) of the U.S. Army is a staff corps (non-combat specialty branch) of the U.S. Army Medical Department (AMEDD) consisting of commissioned medical officers – physicians with either an M.D. or a D.O. degree, at least one ye ...
, is president. At the end of a long journey on foot, the arches flatten, the metatarsals spread, and the foot swells more than after a short one. The toes also need vertical space; a toe cap which is low enough to press on the top of the toe may also cause bruising under the nail, especially if the toe cap is stiff. If the toebox is pointed, the toes may be wedged forwards into the area with inadequate height.
Toenails which protrude unevenly may concentrate force on the toenail; properly-cut nails are therefore also important.
Some susceptible runners may also have Morton's toe
Morton's toe is the condition of having a first metatarsal which is short in relation to the second metatarsal (see diagram). It is a type of brachymetatarsia.
This condition is the result of a premature closing of the first metatarsal's growt ...
. In this variant of human foot anatomy, the second toe extends further out than the great toe
Toes are the digits (fingers) of the foot of a tetrapod. Animal species such as cats that walk on their toes are described as being '' digitigrade''. Humans, and other animals that walk on the soles of their feet, are described as being '' pl ...
. This can make it harder to find shoes with adequate space around the toes.
Treatment
Subungual hematomas can resolve on their own, without treatment being necessary.[ If they are acutely painful,] they may be drained.
Subungual hematomas are treated by either making a hole through the nail into the hematoma ( trephining) within 48 hours of injury, draining the blood and releasing the pressure,[ or, less conservatively, by removing the entire nail.]
In hospital or medical setting, trephining is generally accomplished by using an electrocautery device or an 18-gauge needle. If neither of these is available a heated (red hot) paper clip can be used to drain the blood underneath of the nail. To do this the tip of a paper clip needs to be heated till it's red hot and (the red hot) paper clip gently placed on the center of the hematoma (center of the black area underneath of the nail). A hole will appear in the nail and the blood will drain, relieving the pressure. The hole has to be covered with sterile dressing and the nail should be kept dry afterwards.
Removal of the nail is typically done when the nail itself is disrupted, a large laceration requiring suturing
A surgical suture, also known as a stitch or stitches, is a medical device used to hold body tissues together and approximate wound edges after an injury or surgery. Application generally involves using a needle with an attached length of threa ...
is suspected, or a fracture
Fracture is the separation of an object or material into two or more pieces under the action of stress. The fracture of a solid usually occurs due to the development of certain displacement discontinuity surfaces within the solid. If a displa ...
of the tip of the finger occurs. Although general anesthesia
Anesthesia is a state of controlled, temporary loss of sensation or awareness that is induced for medical or veterinary purposes. It may include some or all of analgesia (relief from or prevention of pain), paralysis (muscle relaxation), ...
is generally not required, a digital nerve block is recommended if the nail is to be removed. For trephination, the block is often more painful than the procedure.[
Hématome sous ungéal 01.jpg, alt=Discoloured thumbnail, grey at the roots, blueish in the center, normal-looking towards the outside edge, Thumb before drainage.
PaperclipRedHotSmall.jpg, alt=Paper clip turned red as a result of the flam, Red hot paper clip.
Hématome sous unguéal 04.jpg, alt=Thumbnail with small hole just above the crescent, a slight amount of blue discolouration next to the hole, After drainage.
Percage-ongle-par-trombone.jpg, Holes in nail.
Complication rates from both forms of treatment are low, and the nail generally recovers to a normal appearance.][
]
See also
* List of cutaneous conditions
Many skin conditions affect the human integumentary system—the organ system covering the entire surface of the body and composed of skin, hair, nails, and related muscle and glands. The major function of this system is as a barrier against t ...
* Turf toe
A metatarsophalangeal joint sprain is an injury to the connective tissue between the foot and a toe (at a metatarsophalangeal joint, one of the joints in the ball of the foot). When the big toe is involved, it is known as "turf toe".
Causes
Turf ...
References
External links
{{General injuries
Conditions of the skin appendages
Foot diseases