Etiologies of Retinal Vasculitides with Prevalence Data
The vast majority of retinal vasculitis cases are NOT caused by systemic vasculitis—only 1.4% of retinal vasculitis cases are directly attributable to classical systemic vasculitides, while nonvasculitic systemic diseases, eye-confined syndromes, and infections account for the overwhelming majority. 1
Prevalence Distribution of Retinal Vasculitis Etiologies
Based on a comprehensive analysis of 207 patients with retinal vasculitis from a major uveitis referral center 1:
Primary/Idiopathic Retinal Vasculitis
- 16.9% (35/207 cases) were primary retinal vasculitis with no associated systemic disease 1
Systemic Non-Vasculitic Inflammatory Diseases
- Sarcoidosis: 6.3% (13/207 cases) - commonly presents with venous involvement and may be associated with branch retinal vein occlusion 2, 1
- Behçet's disease: 6.8% (14/207 cases) - a major cause with strong association to retinal vasculitis 1, 3
Eye-Confined Syndromes
- Pars planitis: 17.4% (36/207 cases) - the most common eye-specific cause 1
Infectious Etiologies
- 14.0% (29/207 cases) were due to intraocular infections including bacterial, viral, fungal, or parasitic causes 4, 1
- Infectious vasculitis tends to exhibit ischemic areas, arterial or venous sheathing or occlusion 4
Classical Systemic Vasculitides
- Only 1.4% (3/207 cases) were directly caused by systemic vasculitis 1
- Giant cell arteritis is the most common arteritic cause when it does occur, affecting medium and large extracranial arteries 2
- Systemic lupus erythematosus patients have a 3.5-fold increased incidence of retinal vascular occlusions and can present with arterial or mixed arteriovenous vasculitis 2
Critical Clinical Distinctions
A common pitfall is assuming that retinal vasculitis indicates systemic vasculitis—this is incorrect in 98.6% of cases. 1 The clinical approach should prioritize:
- Nonvasculitic systemic diseases (sarcoidosis, Behçet's disease, SLE) are far more common than classical vasculitides 1, 3
- Infectious causes must be actively excluded, as they represent 14% of cases and require entirely different management 4, 1
- Eye-confined syndromes like pars planitis account for nearly one-fifth of cases 1
- True inflammatory phlebitis must be distinguished from thrombotic/embolic retinal vein occlusions, which are NOT primary vasculitides despite appearing similar 2
Geographic and Population Variations
The prevalence and spectrum of etiologies show significant geographical variations, particularly for infectious causes 4. Recognizing patient origin, habits, and associated systemic signs enables more effective identification of the causative etiology 4.