MANUAL MINORS
Subungual haematomas are accumulations of blood beneath the nail, typically caused by direct trauma, such as blows or crush injuries. This bleeding generates pressure on the nail bed, causing intense pain, nail discolouration (ranging from red to black), and in severe cases, may compromise the nail’s adherence to the bed.
Although most subungual haematomas are benign, those covering more than 50% of the nail or associated with distal phalanx fractures may require additional interventions.
Diagnosis
The diagnosis of a subungual haematoma is primarily clinical. Patients often report throbbing pain and dark discolouration under the nail following trauma. Physical examination reveals the area of bleeding trapped between the nail and the nail bed.
The extent of the haematoma should be evaluated, and it should be assessed if the nail is separated or deformed. In cases of significant trauma, X-rays are important to rule out fractures of the distal phalanx, which may accompany the haematoma.
Differential Diagnosis
Condition | Main Clinical Characteristics | Key Differentiation |
Onycholysis | Detachment of the nail from the nail bed without direct trauma | Nail separated from the bed, no significant pain or bleeding |
Subungual infection (paronychia) | Swelling, redness, and pain around the nail | Presence of infection, usually without trauma |
Melanonychia | Dark nail pigmentation due to melanin | Progressive colour change, without pain or recent trauma |
Subungual foreign body | Pain and redness under the nail, associated with trauma | Possible history of an object penetrating beneath the nail |
Distal phalanx fracture | Severe pain, deformity, and possible subungual haematoma | Radiographic confirmation of fracture |
Emergency Management
Initial management of a subungual haematoma depends on the extent of the bleeding and the intensity of the pain. If the haematoma is small and the pain is tolerable, conservative management with oral analgesics and observation may suffice. However, if the pain is severe or the haematoma covers more than 25-50% of the nail surface, haematoma evacuation via trephination is recommended.
The trephination procedure involves creating a small hole in the nail, either using an electrocautery device, a sterile needle, or a heated paperclip, to allow the trapped blood to drain, relieving pressure and pain. It is important to ensure the nail is clean and to perform the procedure under sterile conditions to prevent infection.
Definitive Treatment
Definitive treatment involves adequate pain management and monitoring for potential complications. After trephination, the nail should be covered with a sterile dressing, and activities that could cause further trauma to the finger should be avoided.
If the haematoma is associated with a distal phalanx fracture or the nail is severely damaged, surgical evaluation may be necessary to repair the nail bed or treat the fracture.
In general, most subungual haematomas heal without major complications, and the nail will regrow over several months if lost due to the trauma. Antibiotic prophylaxis is only necessary if signs of infection are present.
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