Causes of Conjunctival Hemorrhages
Conjunctival hemorrhages are primarily caused by trauma, systemic hypertension, and acute conjunctivitis, with additional causes including blood disorders, vascular diseases, and increased intrathoracic pressure. 1
Common Causes
Traumatic Causes
- Minor local trauma to the eye is one of the most frequent causes of subconjunctival hemorrhage 1
- Contact lens usage, particularly with poor lens hygiene or prolonged wearing time 2
- Increased intrathoracic pressure from repetitive vomiting or coughing spells 3
Vascular and Systemic Causes
- Systemic hypertension, particularly in older patients 1, 4
- Diabetes mellitus and arteriosclerosis in elderly patients 4
- Bleeding disorders, though studies show their prevalence in recurrent subconjunctival hemorrhage is not significantly different from the general population 5
- Anticoagulation therapy with prolonged prothrombin time 3
Infectious Causes
- Acute conjunctivitis (viral, bacterial, or allergic) 1
- Viral conjunctivitis, particularly Epstein-Barr virus which can present with hemorrhagic conjunctivitis 6
- Adenoviral conjunctivitis, which can cause severe conjunctival injection 6
Less Common Causes
Hematologic Disorders
- Idiopathic thrombocytopenic purpura (ITP) - subconjunctival hemorrhage can be the first presenting clinical feature 7
- Blood dyscrasias and blood clotting disorders 3
Inflammatory Conditions
- Vasculitis associated with conditions such as:
- Sarcoidosis
- Granulomatosis with polyangiitis
- Kawasaki disease
- Microscopic polyangiitis 6
Neoplastic Conditions
- Sebaceous carcinoma - can present with intense bulbar conjunctival injection 6
- Conjunctival lymphoma - can present with chronic palpebral or bulbar follicles 6
- Ocular surface squamous neoplasia - associated with conjunctival hyperemia 6
Risk Factors for Recurrent Subconjunctival Hemorrhage
- Advanced age 4
- Systemic vascular diseases (hypertension, diabetes, arteriosclerosis) 4
- Anticoagulant or antiplatelet therapy 3, 4
- Bleeding disorders (though prevalence is debated) 5
- Systemic and ocular malignancies 4
Clinical Pearls
- Recurrent, bilateral, and severe conjunctival hemorrhages warrant investigation for underlying systemic conditions 3
- Blood pressure should be checked in all patients with subconjunctival hemorrhages, particularly in older individuals 1
- In patients with recurrent subconjunctival hemorrhage without other bleeding manifestations, extensive hemostatic screening may not be necessary based on recent evidence 5
- Subconjunctival hemorrhages from local trauma are more common in summer months 1
- Misdiagnosing sebaceous carcinoma as chronic blepharoconjunctivitis is a common pitfall 2
When to Consider Further Evaluation
- Recurrent or persistent subconjunctival hemorrhages 4
- Presence of other bleeding manifestations 7
- Elderly patients with no obvious traumatic cause 1
- Patients on anticoagulation therapy 3
- When hemorrhage is associated with other ocular or systemic symptoms 4
Remember that while most subconjunctival hemorrhages are benign and self-limiting, they can occasionally be the first sign of a serious underlying condition, particularly when recurrent or associated with other symptoms.