A scalp hematoma is a localized collection of blood beneath the skin of the head, typically appearing as a bump following some form of head trauma. While a simple scalp bruise is common and usually harmless, the severity depends on where the blood accumulates relative to the skull and its protective layers. Understanding the specific location of this blood pooling is key to determining the potential risk involved.
Understanding Scalp Hematoma Anatomy
The scalp is composed of several distinct layers, and the layer where the blood pools determines the type and potential danger of the hematoma. The most common form is a simple contusion or bruise, which is a collection of blood just beneath the skin. More concerning are the deeper types, which are classified by their position relative to the galea aponeurosis and the skull bone.
A cephalohematoma involves blood accumulating in the subperiosteal space, between the skull bone and its outer covering, the periosteum. Because the periosteum is tightly bound to the edges of each skull bone, this swelling cannot cross the cranial suture lines and is confined to one bone. Cephalohematomas are often associated with birth trauma and are typically self-limiting, resolving over time without intervention.
In contrast, a subgaleal hematoma is a potentially more serious collection of blood that forms in the subgaleal space, lying between the galea aponeurosis and the periosteum. This space is loosely connected and spans the entire skull, allowing blood to spread widely and cross suture lines. The potential for a large volume of blood loss makes the subgaleal type a greater concern, particularly in infants, as it can lead to significant blood loss and complications.
Mechanisms of Injury
Scalp hematomas form when blood vessels rupture due to shearing or blunt force trauma to the head. In adults and older children, the most frequent cause is a direct blow from falls, sports participation, or motor vehicle accidents. The impact tears small blood vessels within the scalp layers, allowing blood to leak out and form the swelling.
In newborns and infants, mechanisms relate primarily to the birthing process. A cephalohematoma often results from pressure exerted on the head during passage through the birth canal or from the use of assisted delivery devices, such as forceps or a vacuum extractor. This compression creates a shearing force that separates the periosteum from the skull bone. Subgaleal hematomas in infants are also strongly associated with vacuum extraction, which can rupture emissary veins connecting the scalp’s outer layers to deeper tissues.
Recognizing Serious Symptoms and Emergency Care
Most small scalp hematomas are benign and can be managed at home with simple, conservative measures. Initial care involves the RICE protocol: Rest, Ice application to reduce swelling in the first 24 to 48 hours, and Observation. Over-the-counter pain relievers can be used for discomfort, though NSAIDs like ibuprofen are sometimes avoided initially due to the risk of increased bleeding.
A hematoma becomes serious when the force that caused it is strong enough to result in an underlying skull fracture or bleeding inside the skull. These underlying injuries can cause pressure to build on the brain, leading to dangerous symptoms known as “red flags.” Any sign of neurological change requires immediate emergency medical evaluation.
Urgent symptoms include:
- A severe headache that worsens or does not go away.
- Persistent or forceful vomiting.
- Change in consciousness, such as unusual drowsiness or inability to be fully roused.
- Confusion, slurred speech, or balance issues.
- Weakness on one side of the body.
- Clear or pink fluid leaking from the nose or ears, which may indicate a skull base fracture.
Professional Treatment and Healing Timeline
When a patient presents with a scalp hematoma and concerning symptoms, the medical priority is to rule out intracranial bleeding or a skull fracture. Diagnostic imaging, most commonly a Computed Tomography (CT) scan, is used to visualize the skull and brain tissue to check for internal injury. X-rays may also be used to identify a linear skull fracture, which significantly increases the risk of an associated intracranial injury, especially in small children.
For the majority of simple, localized hematomas, professional treatment focuses on observation, as the body naturally reabsorbs the collected blood over time. Small hematomas typically resolve within a few weeks. Larger subgaleal hematomas, however, can take several months for full resolution.
If a hematoma is massive, continues to grow, or causes severe pressure, medical intervention may be necessary. This can involve surgical drainage, where a small incision is made to aspirate the liquid blood and relieve pressure. For those with confirmed intracranial bleeding, specialized surgery may be required to evacuate the clot and repair the source of the hemorrhage.