What Are the Different Types of Hematomas and What Causes Them?

Hematoma, a common medical condition, is essentially a collection of blood outside of blood vessels. This results from a trauma or injury that causes blood vessels to rupture, allowing blood to accumulate in the surrounding tissues. Although hematomas are often linked to blunt trauma, other factors such as alterations in blood coagulation, certain medical conditions, surgical procedures, and specific therapies can also trigger them. Hematomas can vary greatly in severity and location, leading to a diverse range of symptoms and implications.

Types of Hematoma

Hematomas are classified into several types, each with its unique characteristics and implications. Here's a closer look at some of the common variants:

Subcutaneous Hematomas

These are generally mild and tend to resolve within a few days or weeks. Subcutaneous hematomas are further divided into three categories:

• Petechiae
  These are small, hyperpigmented spots on the skin, often caused by a deficiency of certain coagulation elements. Petechiae are microhematomas, with a diameter not exceeding 3 mm.
• Purpura
  The typical hematoma of purpura is larger than petechiae but smaller than ecchymoses. Purpura causes small purplish bruises on the skin that do not clear with acupressure. The diameter of these lesions is between 3 mm and 1 cm.
• Ecchymosis
  This is a variant of modest subcutaneous hematomas, caused by trauma. The diameter of the hematoma generally exceeds one centimeter, making it a more significant hematoma than petechiae and purpura.

Hematomas of the Brain

Brain hematomas are particularly serious and can be further classified into:

• Cephalohematoma
  This type of hematoma is common in newborns and originates from trauma during childbirth. It spreads slowly and completely asymptomatically, becoming evident after a few days.
• Epidural Hematoma
  This is an accumulation of blood in the space between the skull and the dura mater. It can occur spontaneously or after trauma and requires immediate surgical intervention.
• Subdural Hematoma
  This occurs following a traumatic brain injury, with blood pouring into the subdural space, causing a hematoma.
• Subarachnoid Hematoma
  This hematoma develops in the arachnoid space and often originates from the rupture of a cerebral aneurysm or a head injury. Characteristic symptoms include sudden headache, confusion, loss of consciousness, vomiting, and convulsions. Immediate surgical intervention is required.

Ear Hematoma

Also known as otohematoma or perichondral hematoma, this type of hematoma threatens blood circulation at the level of the underlying cartilage. It occurs after trauma to the ear, with blood escaping from the vessels to flow between the cartilage and the auricular perichondrium.

Perianal Hematoma

This type of hematoma develops inside or near the anus and is often mistaken for an external hemorrhoid. It originates from a rupture of small veins that drain blood from the anus, which can be triggered by violent coughing, heavy lifting, exaggerated efforts, or violent visceral movements.

Surgical Wound Hematoma

Hematoma can also be a complication of a surgical wound, forming a few hours after the operation or later. Certain factors can favor the appearance of post-surgery hematoma, such as alteration of coagulation, arterial hypertension, anticoagulant therapy, and incomplete haemostasis. These hematomas can be very dangerous, especially if they develop in the neck, as they can heavily compress the trachea, leading to a poor prognosis.

Subungual Hematoma

This painful and unpleasant condition originates from the crushing of the nail. The usual treatment involves draining the hematoma by piercing the nail. Although very painful, nail hematoma does not constitute a medical emergency.