Most Common Systemic Cause of Uveitis
Sarcoidosis is the most common systemic disease associated with uveitis, accounting for approximately 7% of all uveitis cases, followed closely by HLA-B27-associated seronegative spondylarthropathies at 6%. 1
Epidemiologic Evidence
The most comprehensive prospective study of 865 uveitis patients found that among cases with definite systemic disease associations (26% of all uveitis), sarcoidosis emerged as the leading systemic cause 1. This finding is corroborated by more recent U.S. data showing sarcoidosis represents 4.98% of all uveitis etiologies when including idiopathic cases 2.
Key Systemic Causes by Frequency:
- Sarcoidosis: 7% of all uveitis cases 1
- HLA-B27-associated spondylarthropathies: 6% of all cases 1, with HLA-B27 acute anterior uveitis being the single most common clinical entity at 17% 1
- Behçet disease: Frequently mentioned in guidelines as requiring distinct therapeutic approaches 3
Important Clinical Context
The answer depends critically on anatomic location:
- For anterior uveitis specifically: HLA-B27-associated disease dominates, representing 50% of anterior uveitis cases and 17% of all uveitis 4, 1
- For posterior/panuveitis: Sarcoidosis and Behçet disease are more prominent systemic associations 4
Geographic and Population Variations
Critical caveat: These data predominantly reflect Western populations (U.S. and Europe) 3, 2. The guidelines explicitly acknowledge that regional differences—such as tuberculosis prevalence—significantly influence the systemic disease spectrum 3. In low- and middle-income countries, infectious causes (tuberculosis, toxoplasmosis) account for up to 50% of cases versus only 11-21% in high-income countries 5.
Clinical Recognition
Most systemic diseases causing uveitis are not suspected prior to eye involvement and are only recognized after diagnostic workup 1. This underscores the importance of systematic evaluation rather than relying on obvious systemic symptoms.
The majority of uveitis cases (42-51%) remain idiopathic despite thorough investigation 2, 1, meaning that even when no systemic cause is identified, this represents the most common scenario overall.