Subungual hematoma

A laceration of the nail bed causes bleeding into the constricted area underneath the hard nail plate. 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 may occur. The pressure of the blood blister may cause separation of nail plate from the nail bed (onycholysis), 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. ==Causes==

for foot to extend. Left: Proper fit The condition is caused by a traumatic injury, such as slamming a finger 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. runner's toe, or black toenail. In a marathon, several percent of runners may be affected. 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. Some susceptible runners may also have Morton's toe. In this variant of human foot anatomy, the second toe extends further out than the great toe. 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. they may be drained. In a hospital or medical setting, trephining is generally accomplished by using an electrocautery device or an 18-gauge needle. The hole is covered with sterile dressing and must be kept dry afterwards. Removal of the nail is typically done when the nail itself is disrupted, a large laceration requiring suturing is suspected, or a fracture of the tip of the finger occurs. Although general anesthesia 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. Complication rates from both forms of treatment are low, and the nail generally recovers to a normal appearance. 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. 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; note drainage hole. == See also ==