Medicine – Scleritis

Scleritis is a painful inflammatory disorder affecting the sclera, the dense connective tissue forming the outer coat of the eye. It is clinically important because it may indicate an underlying systemic autoimmune or vasculitic disease and, in severe cases, can threaten vision.

A substantial proportion of patients have an associated systemic disorder, although scleritis can also occur without an identifiable underlying cause.

1. Clinical Presentation

The characteristic symptom of scleritis is severe, deep ocular pain.

The pain is often described as boring or aching and may radiate to the forehead, brow, temple, or jaw. It can be worse at night and may be aggravated by eye movement.

The affected eye usually develops deep redness, and patients may also experience photophobia, tearing, and reduced vision.

2. Appearance of the Eye

Scleritis causes inflammation of the deeper episcleral and scleral vessels, producing a characteristic deep red or violaceous appearance.

The deeper vessels generally do not blanch completely with topical vasoconstrictors, which can help distinguish scleritis from more superficial episcleritis.

3. Rheumatoid Arthritis

Rheumatoid arthritis (RA) is one of the classic systemic diseases associated with scleritis.

Ocular inflammation may occur in patients with longstanding or severe rheumatoid disease.

RA can also be associated with particularly destructive forms of scleral inflammation, including necrotising scleritis.

Therefore:

RA + painful red eye → consider scleritis.

4. Granulomatosis with Polyangiitis

Granulomatosis with polyangiitis (GPA), formerly called Wegener’s granulomatosis, is another particularly important association.

GPA is a systemic small- to medium-vessel vasculitis that commonly involves the respiratory tract and kidneys but may also produce significant ocular disease.

Scleritis can sometimes be an important clue to previously unrecognised systemic vasculitis.

5. Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) can be associated with scleral inflammation.

Although scleritis is less characteristic of SLE than some other ocular manifestations, a painful red eye in a patient with lupus warrants careful assessment for significant ocular inflammation.

6. Ankylosing Spondylitis

Ankylosing spondylitis and the broader group of spondyloarthritides are strongly associated with inflammatory eye disease.

However, an important distinction is that their classic ocular association is acute anterior uveitis, rather than scleritis.

Scleritis can occur in association with spondyloarthritis, but it is considerably less characteristic.

7. Inflammatory Bowel Disease

Inflammatory bowel disease, including Crohn disease and ulcerative colitis, may be associated with ocular inflammatory manifestations.

These include episcleritis and anterior uveitis, with scleritis occurring less commonly.

Nevertheless, IBD should be considered when scleritis occurs together with gastrointestinal symptoms or known inflammatory bowel disease.

8. Sarcoidosis

Sarcoidosis can involve numerous structures within the eye.

Its classic ocular manifestation is uveitis, but scleral inflammation can occasionally occur.

Therefore, sarcoidosis remains a possible systemic association of scleritis, although it is not among the most characteristic causes.

9. Infectious Scleritis

Although many cases are immune-mediated, infection must also be considered, particularly when the clinical context is atypical.

Infectious scleritis is important because treating an unrecognised infection with immunosuppression alone can worsen the disease.

10. Herpes Viruses

Both herpes simplex virus (HSV) and varicella-zoster virus (VZV) can cause infectious or infection-associated scleral inflammation.

VZV-associated disease may occur in the context of herpes zoster ophthalmicus.

Other bacterial or fungal infections may also cause infectious scleritis, particularly following ocular surgery, trauma, or other disruption of the scleral surface.

11. Types of Scleritis

Scleritis can broadly be divided into anterior and posterior disease.

Anterior scleritis is more common and can be classified into diffuse, nodular, and necrotising forms.

Necrotising disease is particularly concerning because it can cause progressive destruction and thinning of the sclera.

12. Posterior Scleritis

Posterior scleritis affects the sclera behind the equator of the globe and may therefore be less obvious on external inspection.

Patients can present with deep ocular pain, headache, reduced vision, or visual distortion.

Because the inflammation is posterior, imaging such as ocular ultrasonography may be needed to support the diagnosis.

13. Scleritis versus Episcleritis

This distinction is clinically useful.

Scleritis generally causes severe deep pain, marked tenderness and deeper violaceous redness. It has a stronger association with serious systemic autoimmune disease and may threaten vision.

Episcleritis is a more superficial inflammatory condition. It usually causes mild discomfort or irritation rather than severe pain and is generally self-limiting.

Therefore:

Very painful red eye → think scleritis rather than simple episcleritis.

14. Complications

Severe scleritis can lead to important ocular complications including scleral thinning, keratitis, uveitis, glaucoma, cataract, retinal or choroidal complications, and visual loss.

Necrotising disease carries particularly significant risk of structural ocular damage.

15. Treatment

Treatment depends on the severity and underlying cause.

Non-infectious anterior scleritis may require systemic NSAIDs, while more severe disease may require systemic corticosteroids.

Severe, recurrent, necrotising, or vasculitis-associated disease may require immunosuppressive or biologic therapy under specialist care.

If an infectious cause is identified, appropriate antimicrobial or antiviral treatment is essential rather than simply escalating immunosuppression.

16. Scleritis – Note Form

Definition: deep inflammation of the sclera.

Typical symptom: severe, deep, boring ocular pain.

Eye appearance: deep red or violaceous inflammation.

Important autoimmune association: rheumatoid arthritis.

Important vasculitic association: granulomatosis with polyangiitis (GPA; formerly Wegener’s granulomatosis).

Other autoimmune association: SLE.

Inflammatory bowel disease: associated with ocular inflammation; episcleritis and uveitis are more common, but scleritis can occur.

Ankylosing spondylitis: can be associated, although anterior uveitis is the classic ocular manifestation.

Sarcoidosis: possible association, but uveitis is more characteristic.

Infectious causes: include HSV and VZV, as well as bacterial and fungal causes in appropriate settings.

Severe form: necrotising scleritis may cause scleral destruction and is strongly associated with systemic autoimmune or vasculitic disease.

Treatment: systemic anti-inflammatory treatment or immunosuppression for non-infectious disease; targeted antimicrobial treatment when infection is responsible.

Key Clinical Pattern

Remember scleritis as:

Severe deep eye pain + deep red/violaceous eye + systemic autoimmune disease.

The two particularly important systemic associations to remember are:

Rheumatoid arthritis + GPA → scleritis.

Also remember the distinction:

Scleritis → severe pain + potentially sight-threatening.

Episcleritis → mild discomfort + usually benign.

And for examination purposes:

Ankylosing spondylitis → classically anterior uveitis.

Sarcoidosis → classically uveitis.

RA/GPA → particularly important associations with scleritis.