Raccoon eyes or periorbital ecchymosis is a sign

Medical sign

A medical sign is an objective indication of some medical fact or characteristic that may be detected by a physician during a physical examination of a patient....

 of basal skull fracture, a craniotomy

Craniotomy

A craniotomy is a surgical operation in which a bone flap is temporarily removed from the skull to access the brain. Craniotomies are often a critical operation performed on patients recording, brain imaging, and for neurological manipulations such as electrical stimulation and chemical...

 that ruptured the meninges, or (rarely) certain cancers. Bilateral subconjunctival hemorrhage occurs when damage at the time of a facial fracture tears the meninges

Meninges

The meninges is the system of membranes which envelopes the central nervous system. The meninges consist of three layers: the dura mater, the arachnoid mater, and the pia mater. The primary function of the meninges and of the cerebrospinal fluid is to protect the central nervous system.-Dura...

 and causes the venous sinuses to bleed into the arachnoid villi and the cranial sinuses. In layman's terms, blood from skull fracture seeps into the soft tissue around the eyes. Raccoon eyes may be accompanied by Battle's sign

Battle's sign

In medical terminology, Battle's sign, also mastoid ecchymosis, is an indication of fracture of middle cranial fossa of the skull, and may suggest underlying brain trauma. Battle's sign consists of bruising over the mastoid process, as a result of extravasation of blood along the path of the...

, an ecchymosis

Ecchymosis

An ecchymosis is the medical term for a subcutaneous purpura larger than 1 centimeter or a hematoma, commonly called a bruise. It can be located in the skin or in a mucous membrane.-Presentation:...

 behind the ear. These signs may be the only sign of a skull fracture, as it may not show on an X-ray. They may not appear until up 2–3 days after the injury. It is recommended that the patient not blow their nose, cough vigorously, or strain to prevent further tearing of the meninges.

Raccoon eyes may also be a sign of disseminated neuroblastoma

Neuroblastoma

Neuroblastoma is the most common extracranial solid cancer in childhood and the most common cancer in infancy, with an annual incidence of about 650 cases per year in the US , and 100 cases per year in the UK . Close to 50 percent of neuroblastoma cases occur in children younger than two years old...

 or of amyloidosis

Amyloidosis

In medicine, amyloidosis refers to a variety of conditions whereby the body produces "bad proteins", denoted as amyloid proteins, which are abnormally deposited in organs and/or tissues and cause harm. A protein is described as being amyloid if, due to an alteration in its secondary structure, it...

 (multiple myeloma

Multiple myeloma

Multiple myeloma , also known as plasma cell myeloma or Kahler's disease , is a cancer of plasma cells, a type of white blood cell normally responsible for the production of antibodies...

). It can also be a side effect of using cocaine.

Depending on cause, raccoon eyes always require urgent consultation and management, that is surgical

Surgery

Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...

 (facial fracture or post-craniotomy) or medical

Medicine

Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....

(neuroblastoma or amyloidosis).