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)
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🔴 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 |