Lab Tests to Consider
Q. Is there a surefire way to confirm an episcleritis diagnosis?
A. Most patients who present with symptoms have simple episcleritis. This form of the disease is most often unilateral, with marked tenderness to touch, pain upon movement and mild photophobia, says Andrew S. Gur-wood, O.D., of Pennsylvania College of Optometry in Philadelphia. It occurs most often in young adults (18-25) and is more prevalent in women than in men.1,2
The cornea remains intact, and injection is generally sectoral with the apex closest to the cornea. Most often this area is within the interpalpebral area, temporally more often than nasally, says Steven Ferrucci, O.D., chief of optometry at the Veterans Affairs Ambulatory Care Center in Sepulveda, Calif.
Episcleritis can recur at 1-3 months, with episodes usually lasting 7-10 days.
You can rule out a conjunctival abrasion with fluorescein staining, says Lawrence Woodard, M.D., of Omni Eye Services in Atlanta. You can also rule out viral conjunctivitis by taking a careful history and by the absence of conjunctival follicles.
Simple episcleritis is often self-limiting and may not require treatment. Use vasoconstrictors with caution because the associated focal injection is a significant clinical sign. Removing this key signal, without completely resolving the underlying cause may lead to recurrences and, ultimately, a worsening condition, Dr. Gurwood warns.
In patients with severe inflammation, topical steroids may be indicated. If a patient does not respond to topical steroid therapy within three weeks, be sure its episcleritis and not scleritis, Dr. Ferrucci says.
Complete blood count (CBC).
Erythrocyte sedimentation rate (ESR).
Fluorescent treponemal antibody absorption (FTA-ABS).
Reactive plasma reagent (RPR) for syphilis.
Chest x-ray (CXR).
Purified protein derivative (PPD) for sarcoidosis and tuberculosis.
Angiotensin converting enzyme (ACE) for sarcoidosis, Bartonella henselae and quintana (cat-scratch disease).
Rheumatoid factor (RF) for arthritis.
Antinuclear antibodies (ANA) for lupus.
To differentiate the two, note the condition of the episcleral vessels. In episcleritis the vessels will be engorged but not distorted, as with scleritis, Dr. Woodard says. Also, scleritis will involve the deep episcleral vessels.
If you suspect episcleritis, blanch the conjunctival vessels with 2.5% epinephrine to visualize the episcleral vessels. If you suspect scleritis, use 10% epinephrine to examine the deeper vessels. If these deeper vessels are involved, scleritis is the diagnosis.
Simple episcleritis may indicate an antibody response to an irritant. Often, there is no underlying cause.
Nodular episcleritis, however, nearly always indicates an underlying systemic infectious or inflammatory condition such as tuberculosis, rheumatoid arthritis or syphilis. The pathognomonic features of nodular episcleritis are small, mobile, elevated nodules within the boundaries of the injected region in addition to the signs seen with the simple form, Dr. Gurwood says.
Q. Are there any lab test I can order to confirm the diagnosis?
A. Lab tests can help you distinguish between simple and nodular episcleritis. Also, Dr. Ferrucci says, a careful history can help rule out a variety of associated conditions. Your suspicions should heighten when episcleritis is recalcitrant, recurrent, unusually severe, chronic, unremitting or shows symptoms of the nod-ular form. When you suspect an underlying condition, several tests can help point you to the correct diagnosis (see table above).
Whenever episcleritis requires lab testing, inform the patients intern-ist. Also, consider a rheumatologic consult, as the patient may need oral steroids or oral immunosuppressive medications. Your experience and comfort level should dictate if and when to refer to an anterior segment specialist, Dr. Gurwood says.
1. Berkow R, Fletcher A. Ophthalmologic Disorders. In: The Merck Manual of Diagnosis and Therapy. 15th ed. Rahway, N.J.: Merck Sharp & Dohme Research Laboratories, 1987:2223-42.
2. Berkow R, Fletcher A. Conjunctiva: Episcleritis. In: The Merck Manual of Diagnosis and Therapy. 15th ed. Rahway, N.J.: Merck Sharp & Dohme Research Laboratories, 1987:2223.