What causes subconjunctival hemorrhage?

Causes of Subconjunctival Hemorrhage

Subconjunctival hemorrhage results from rupture of small blood vessels beneath the conjunctiva, with causes ranging from benign mechanical factors to serious systemic and ocular malignancies that require investigation when hemorrhages are recurrent or persistent. 1

Common Benign Causes

Mechanical and Traumatic Factors

• Trauma is a leading cause, particularly in younger patients 2
• Contact lens usage, especially with poor hygiene or prolonged wearing time, commonly causes subconjunctival hemorrhage 3, 2
• Valsalva maneuvers from coughing, sneezing, straining, vomiting, or heavy lifting can rupture conjunctival vessels 2
• Childbirth can cause bilateral subconjunctival hemorrhages due to sustained pushing efforts, though this is relatively rare 4

Infectious Causes

• Viral conjunctivitis frequently presents with petechial and subconjunctival hemorrhage 1
• Adenoviral conjunctivitis produces distinctive subconjunctival hemorrhage patterns with severe conjunctival injection 1, 3
• Epstein-Barr virus can present with hemorrhagic conjunctivitis, including subconjunctival hemorrhage and periorbital edema 5, 3
• Measles (rubeola) causes bilateral subconjunctival hemorrhages along with other conjunctival findings 5

Medication-Related Causes

• Anticoagulation therapy, including warfarin and direct oral anticoagulants, is a well-established medication-related cause 1
• Antiplatelet agents and NSAIDs can predispose to subconjunctival hemorrhage 6

Systemic Vascular Risk Factors (Elderly Patients)

• Hypertension is more common among elderly patients with subconjunctival hemorrhage 2
• Diabetes mellitus and arteriosclerosis are additional vascular risk factors in older populations 2

Serious Causes Requiring Investigation

When to Suspect Malignancy

Recurrent or persistent subconjunctival hemorrhage without identifiable cause warrants further workup, as it may indicate underlying ocular malignancy. 1

• Ocular adnexal lymphoma may initially present as recurrent subconjunctival hemorrhage with a characteristic salmon-pink conjunctival lesion 1, 7
• Sebaceous carcinoma appears as yellowish discoloration with a subconjunctival multilobulated yellow mass and intense bulbar conjunctival injection 1, 3
• Conjunctival melanoma presents as painless brown or fleshy-pink lesions 1
• Ocular surface squamous neoplasia is associated with conjunctival hyperemia 3

Hematologic Disorders

• Idiopathic thrombocytopenic purpura can present with subconjunctival hemorrhage as the first clinical manifestation, though this is rare 8
• Bleeding disorders should be considered in recurrent cases, though hemostatic abnormalities are not more prevalent in patients with recurrent spontaneous subconjunctival hemorrhage compared to the general population 6
• Von Willebrand disease prevalence is not significantly elevated in recurrent subconjunctival hemorrhage patients 6

Systemic Vasculitis

• Vasculitis associated with sarcoidosis, granulomatosis with polyangiitis, Kawasaki disease, and microscopic polyangiitis can cause conjunctival hemorrhages 3

Clinical Evaluation Algorithm

Initial Assessment

• Identify obvious causes: recent trauma, Valsalva maneuver, contact lens use, acute conjunctivitis 2
• Review medications: anticoagulants, antiplatelet agents, NSAIDs 1, 6
• Check blood pressure and assess for systemic vascular disease in elderly patients 2

Red Flags Requiring Further Investigation

• Recurrent hemorrhages without identifiable cause 1, 2
• Persistent hemorrhages that do not resolve as expected 2
• Associated conjunctival nodules or masses requiring biopsy 1
• Salmon-pink lesions suggesting lymphoma 1, 7
• Yellowish discoloration or multilobulated masses suggesting sebaceous carcinoma 1

Common Pitfall

Misdiagnosing sebaceous carcinoma as chronic blepharoconjunctivitis is a frequent error that delays appropriate treatment 3. Any chronic conjunctival inflammation with recurrent hemorrhage should prompt consideration of malignancy.

Laboratory Testing Considerations

Routine hemostatic screening or second-level coagulation tests are not useful in patients with recurrent subconjunctival hemorrhage who have no other bleeding manifestations, as the prevalence of hemostatic alterations is not different from the general population 6. However, if systemic bleeding symptoms are present, hematologic evaluation including platelet count and coagulation studies is warranted 8.