Brief Outline of Black Nail
A subungual haematoma is bleeding under the toenail caused by an injury or infection to the nail bed. Crushing injury is the most common mechanism for this type of injury. The bleeding under the nail causes pressure and pain to the nail bed. The pocket of blood maybe small or cover the whole area under the nail.
Anatomy and physiology
The nail protects the area under the toenail, the nail bed, but when crushing trauma, an object under the nail, or infection causes damage to this soft area, bleeding may occur. Because the nail is a hard surface, it holds the blood in and this bleeding causes pressure and pain. Depending on the initial injury, the bone underneath may also be involved.
Cause of injury
Crushing injury to the toe. Foreign object under the nail causing a laceration to the nail bed. Infection under the nail causing bleeding.
Signs and symptoms
Pain and pressure under the nail. Red, maroon or other dark colour under the nail.
Complications if left untreated
The bleeding and resulting pressure under the nail may cause damage to the underlying tissues, killing them over time. The nail may fall off and this could lead to infection if not treated properly. If the bone was fractured during the initial injury, chronic pain may result.
Rest, ice and elevation. If the nail comes off, it is important to keep it covered and protected. If the possibility of a fracture exists, such as with a crushing injury, seek medical attention.
Rehabilitation and prevention
The nail may need to be removed during treatment, or may fall off on its own, leaving the nail bed exposed. It is important to keep this area protected to prevent infection. It is also important to protect the affected toe while it is healing. Padding over the toes may be needed. Avoiding impact to the toes and protecting them during activities will help prevent this injury.
A subungual haematoma will usually respond well to treatment, although in cases involving more than 25% of the nail bed and pressure that is unrelieved by initial treatments, a physician may need to drain the blood from the nail bed. If an infection is the cause, oral or topical antibiotics may be required.