Laboratory Testing for Recurrent Scleritis
For patients with recurrent scleritis, a comprehensive autoimmune and inflammatory workup is essential as up to 50% of cases are associated with underlying systemic diseases.
Initial Laboratory Evaluation
Core Laboratory Tests
- Complete blood count (CBC) with differential
- Comprehensive metabolic panel (including renal and liver function)
- Erythrocyte sedimentation rate (ESR)
- C-reactive protein (CRP)
- Rheumatoid factor (RF)
- Antinuclear antibody (ANA)
- Anti-neutrophil cytoplasmic antibodies (ANCA) - both PR3 and MPO
- Anti-cyclic citrullinated peptide (anti-CCP) antibodies
Expanded Autoimmune Panel
- Anti-Sjögren syndrome A/B antibodies (SSA/SSB)
- Anti-double-stranded DNA (anti-dsDNA)
- Anti-nucleosome antibody (ANuA)
- Complement levels (C3, C4, CH50)
- Serum immunoglobulin levels (IgG, IgA, IgM)
- IgG4 levels (for potential IgG4-related disease) 1
Infectious Disease Screening
- Tuberculosis testing (QuantiFERON-TB Gold or PPD)
- Syphilis serology (RPR/VDRL and confirmatory test)
- Varicella zoster virus (VZV) serology 2
- Herpes simplex virus (HSV) serology
Targeted Testing Based on Clinical Suspicion
For Suspected Vasculitis
- Chest imaging (CT or X-ray)
- Angiotensin-converting enzyme (ACE) levels (for sarcoidosis) 3
- Serum lysozyme (for sarcoidosis) 3
For Suspected Connective Tissue Disease
- Anti-thyroid antibodies (anti-thyroid peroxidase, anti-thyroglobulin) 3
- Orbital imaging (CT or MRI) if thyroid eye disease is suspected 3
For Suspected Inflammatory Bowel Disease
- Fecal calprotectin
- HLA-B27 (especially with concurrent uveitis)
Tissue Sampling
- Consider conjunctival biopsy with immunofluorescence studies if ocular mucous membrane pemphigoid is suspected 3
- Scleral biopsy may be necessary in cases of necrotizing scleritis or when infection is suspected
Monitoring Parameters
- Regular monitoring of ESR, CRP, and renal function is recommended during treatment
- For patients on immunosuppressive therapy, appropriate monitoring of drug levels and side effects
Clinical Significance
The laboratory evaluation is critical as scleritis may be the initial manifestation of serious systemic diseases like rheumatoid arthritis or ANCA-associated vasculitis 4, 5. Studies show that 30-40% of scleritis patients have an underlying systemic autoimmune condition 4.
In patients with systemic lupus erythematosus (SLE) and scleritis, laboratory findings typically show high-titer ANA, elevated anti-dsDNA, positive anti-nucleosome antibodies, and decreased complement levels 6.
Important Considerations
- Negative laboratory results do not exclude underlying systemic disease; clinical vigilance must be maintained
- Laboratory testing should be repeated periodically in idiopathic cases as systemic disease may manifest later
- The pattern and severity of scleritis (diffuse, nodular, or necrotizing) may guide the intensity of systemic workup
- Collaboration with rheumatology is essential for proper interpretation of results and management
Early identification of underlying systemic disease through appropriate laboratory testing is crucial for reducing both ocular and systemic morbidity in patients with recurrent scleritis 5.