The scalp is highly vascularized, and blunt trauma can lead to blood vessel rupture. In some cases, scalp hematomas may develop without any visible laceration of the scalp.
Subcutaneous Hematoma
Subcutaneous hematomas are typically localized, with a firmer texture at the periphery compared to the central area. These hematomas lack fluctuation and are sometimes misdiagnosed as depressed skull fractures. CT imaging may be needed for differentiation in certain cases. Subcutaneous hematomas are usually small and may be monitored or treated with immediate cold compresses after the injury. Most resolve spontaneously within a short period.
Subgaleal Hematoma
Subgaleal hematomas are not confined by cranial sutures and can spread across the entire scalp. These hematomas are soft to the touch and may exhibit significant fluctuation. Smaller subgaleal hematomas can be managed with compression bandages until spontaneous absorption occurs. For larger hematomas in patients with normal coagulation function, aspiration of the hematoma should be performed under strict aseptic conditions, followed by compression bandaging. If the hematoma persists despite repeated aspiration and compression, underlying causes such as coagulopathy should be investigated. In infants and young children, large subgaleal hematomas can result in anemia and even hypovolemic shock. In cases of infected hematomas, the scalp should be incised to drain the infection.
Subperiosteal Hematoma
Subperiosteal hematomas are generally confined by the cranial sutures and have a high tension, with noticeable fluctuation. It is important to assess for associated skull fractures. The management principles are similar to those for subgaleal hematomas. However, when a skull fracture is present, compression bandaging is not advisable, as it may allow blood to pass through the fracture line into the cranial cavity, potentially leading to an epidural hematoma.