A scalp hematoma describes a collection of blood that gathers in the tissue layers of the scalp, typically following an injury. When blood vessels are damaged, blood can leak out and become trapped, forming a noticeable lump or swelling. This accumulation occurs outside of the skull itself and does not directly involve the brain. While the appearance of a bump on the head can be alarming, most scalp hematomas are confined to the soft tissues.
Causes and Types of Scalp Hematomas
Trauma to the head is the primary reason scalp hematomas develop. In adults, this often results from falls, vehicle accidents, or assaults. For newborns, the cause is frequently related to the birthing process, including pressure on the baby’s head as it moves through the birth canal or the use of instruments like vacuum extractors or forceps.
A cephalohematoma is a collection of blood that occurs beneath the periosteum, a dense membrane that covers the surface of the skull bones. The swelling does not cross the suture lines, which are the fibrous joints between the skull’s bones. This boundary keeps the hematoma confined to a single cranial bone, and it is a common, generally harmless condition in infants.
A subgaleal hematoma, however, is located in the potential space between the periosteum and a fibrous layer of tissue known as the galea aponeurotica. Unlike a cephalohematoma, this type of hematoma is not restricted by suture lines and can spread across the entire scalp. This ability to expand means a significant volume of blood can accumulate, making the subgaleal hematoma a more serious condition that poses risks of substantial blood loss, particularly in infants.
Recognizing the Signs and Symptoms
A scalp hematoma typically appears as a soft, raised lump on the head. This swelling may feel spongy or firm to the touch and can develop hours or even a day after the initial injury. The blood that has collected outside the vessels can irritate the surrounding tissue, leading to pain.
When to Seek Medical Attention
It is important to seek medical care if a head injury is followed by specific warning signs. These include:
- A headache that progressively worsens
- Repeated vomiting, confusion, or unusual drowsiness
- Changes in vision, slurred speech, or seizures
- Pupils that are different sizes
- In infants, extreme irritability, lethargy, or signs of significant blood loss like pale skin
Any rapid increase in the size of the hematoma also warrants a visit to a healthcare professional.
Medical Diagnosis and Treatment Approaches
A diagnosis is often made through a physical examination of the head. A doctor will assess the size and characteristics of the swelling and ask about the circumstances of the injury. If there are concerns about the severity of the trauma or if the person is experiencing neurological symptoms, imaging tests may be ordered. An ultrasound, CT scan, or MRI can help determine the extent of the hematoma and rule out more serious issues like a skull fracture or bleeding inside the skull.
For the majority of cases, treatment consists of careful observation as the hematoma resolves on its own. Pain can be managed with over-the-counter medications. In rare instances, such as when a hematoma is exceptionally large, persists for an extended period, or shows signs of infection like increased redness and warmth, a doctor might need to intervene. This could involve a procedure called aspiration, where the collected blood is drained using a needle.
The Healing Process and Complications
As the blood breaks down, the swelling gradually subsides. The skin over the hematoma may change color, similar to a bruise, as the healing progresses. Most of these injuries heal completely without any lasting effects.
Although uncommon, complications can arise. In newborns, the breakdown of a large number of red blood cells from a hematoma can lead to jaundice (a yellowing of the skin and eyes), which may require medical treatment. For larger hematomas, particularly the subgaleal type, the amount of blood lost into the scalp can be enough to cause anemia. In some cases, a hematoma can calcify, meaning it hardens into a bony lump over time, which is primarily a cosmetic issue.