Bruising Behind the Ears (Battle's Sign / Mastoid Ecchymosis)

What is Battle's Sign?

Battle's Sign refers to bruising over the mastoid process (the bony prominence behind the ear), typically developing 24–72 hours after a significant head injury. It results from blood tracking into the mastoid region along the posterior auricular vessels, and is a classic indicator of a middle cranial fossa basilar skull fracture.

The predictive value of Battle's Sign is clinically significant: studies demonstrate that its presence carries a greater than 75% probability of an underlying basilar skull fracture, a 66% probability of an associated brain lesion, and in some series, a near 100% correlation with skull base fracture.

Evidence-Based Statistic: Battle's Sign predicts basilar skull fracture with >75% probability. Studies show a 66% chance of brain lesion and near-100% association with skull base fracture when present.

 

PRIMARY: Simon LV, Newton EJ. Basilar Skull Fractures. StatPearls [Updated Aug 2023]. PMID: 29489178

SUPPORTING: Solai CA, et al. Clinical Signs of Basilar Skull Fracture and Their Predictive Value in Diagnosis of This Injury. J Trauma Nurs. 2018;25(5):301–306. [PMID: 30216260]

SUPPORTING: Murthy TM, et al. Battle's sign — a clinical sign of basilar skull fracture. J Clin Diagn Res. 2017;11(4):TD01–TD02. doi:10.7860/JCDR/2017/26282.9617

Common Causes

  • Basilar skull fracture (middle cranial fossa)
  • Severe head injury
  • Road traffic accidents
  • Falls from height
  • Sports injuries
  • Assault-related trauma

Investigations

  • CT Head (preferred initial imaging)
  • CT Skull Base
  • MRI Brain (for soft tissue and nerve assessment)
  • Neurological examination
  • Hearing assessment (audiometry)

🔴 RED FLAGS — Seek Emergency Care Immediately

• Loss of consciousness

• Clear fluid from ears or nose (CSF leak)

• Seizures

• Severe or worsening headache

• Repeated vomiting

• Limb weakness

• Confusion or agitation

• Progressive drowsiness