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304 Episcleritis/Scleritis

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BASIC INFORMATION
Advanced scleritis: presence of signs of scleritis
and any or all of the following: ○ Neoplasia
Conjunctival neoplasia (e.g., mast cell
■
Definition • Stromal keratitis tumor; hemangiosarcoma; histiocytoma)
• Episcleritis: focal or diffuse inflammation of • Inflammation of the vitreous ■ Extension of intraocular tumor
the episclera, a thin, collagenous, and vascular • Secondary glaucoma (p. 387) • Granuloma (e.g., foreign body; parasitic:
membrane that makes up the superficial layer • Retinochoroidal degeneration (p. 883) Onchocerca spp)
of the sclera • Cystic/bullus retinal detachment (p. 885) • Granulation tissue
• Scleritis: inflammation and thickening of the • Scleral thinning, which may cause subcon- • Diffuse episcleritis/scleritis; other causes of
anterior and posterior sclera, involving the junctival iris prolapse or staphyloma red eye
cornea, uvea, and retina in advanced cases ○ Conjunctivitis
Etiology and Pathophysiology ○ Glaucoma
Synonyms Episcleritis/scleritis: ○ Uveitis
Collie granuloma, fibrous histiocytoma, nec- • Often idiopathic; immune-mediated disease
rotizing scleritis, nodular fasciitis, proliferative • Association with positive Toxoplasma titers Initial Database
keratoconjunctivitis, limbal granuloma, nodular has been found. • Complete ophthalmic examination (p. 1137),
granulomatous episcleritis/episclerokeratitis Episcleritis, primary: including
(NGE), non-necrotizing deep scleritis, non- • Simple (uncommon): not associated with ○ Schirmer tear test (normal > 15 mm in
necrotizing superficial scleritis systemic disease; usually responsive to 1 minute for dogs)
therapy; often self-limited ○ Fluorescein dye application
Epidemiology • Nodular (common): proposed pathogenesis ○ Intraocular pressures (normal > 15 mm Hg
SPECIES, AGE, SEX of nodular granulomatous episcleritis involves and < 25 mm Hg)
Dogs; no age or sex predisposition production of inflammatory mediators by T ○ Examination of the anterior and posterior
lymphocytes and subsequent chemotaxis of segments of the eye
GENETICS, BREED PREDISPOSITION histiocytes. • Cytologic examination of nodular lesion; may
Spaniel breeds, especially American cocker spaniel Episcleritis, secondary: help differentiate neoplasia from inflamma-
(episcleritis, scleritis), collie, Shetland sheepdog • Develops as a result of inflammation tion (see Differential Diagnosis above)
extending to episclera from severe intra-
Clinical Presentation ocular diseases, including panophthalmitis/ Advanced or Confirmatory Testing
DISEASE FORMS/SUBTYPES endophthalmitis, chronic glaucoma, or ocular • Episcleral biopsy and histopathologic evalu-
• Episcleritis: primary (simple, nodular) or trauma ation (nodular granulomatous episcleritis
secondary Scleritis, non-necrotizing granulomatous: characterized by histiocytes, plasma cells,
• Scleritis: necrotizing granulomatous or • Characterized by infiltration of lymphocytes, lymphocytes, and fibroblasts)
non-necrotizing granulomatous plasma cells, and macrophages • Serologic titers for infectious diseases if
• Granulomatous response seen in cornea with supportive systemic signs (e.g., T. gondii;
HISTORY, CHIEF COMPLAINT corneal extension E. canis)
Episcleritis: • ± Secondary uveitis • Laboratory testing: canine rheumatoid factor,
• Pinkish-red growth on eye (nodular) • Damaged sclera replaced by fibrous tissue antinuclear antibody, lupus erythematosus
• Red eye (diffuse) and/or cystic spaces, causing scleral thinning cell identification negative in most cases
• Typically painless after several episodes • Ocular ultrasound if ocular media opaque,
Scleritis: Scleritis, necrotizing granulomatous (rare): compromising evaluation of deeper ocular
• Signs of ocular pain noted by owner: pho- • Aggressive disease causing necrosis of scleral structures; useful for ruling out concurrent
tophobia, blepharospasm, excessive tearing, collagen ocular abnormalities (i.e., retinal detachment)
engorged scleral vessels, ink-tan colored • Typically affects anterior and posterior
sector lesions near the limbus segments of the eye TREATMENT
• Commonly associated with secondary uveitis,
PHYSICAL EXAM FINDINGS glaucoma, and retinal detachment Treatment Overview
Episcleritis: • Ehrlichia canis infection reported in certain Many forms of episcleritis respond well to
• Conjunctival hyperemia cases topical corticosteroid application, tapered
• Engorgement of episcleral vessels gradually to the lowest effective frequency.
• Thickening of episclera (partial or diffuse) DIAGNOSIS Therapeutic goals are to promote regression
• With nodular forms, multiple or single, of disease, eliminate ocular pain, and keep
raised, pinkish-red mass(es) may be apparent Diagnostic Overview disease in remission with maintenance therapy.
at limbus; typically bilateral Episcleritis/scleritis should be strongly suspected Treatment of NGE and scleritis often requires
• ± Perilimbal keratitis with corneal vasculariza- on the clinical appearance of the affected topical and systemic therapies, including oral
tion and edema (e.g., nodular granulomatous globe(s), ruling out other causes of red eye, and prednisone ± azathioprine.
episclerokeratitis) response to treatment. If the ocular disease does
Scleritis: not respond to medical therapy as expected, Acute General Treatment
• Conjunctival hyperemia episcleral biopsy (usually referrable procedure) To be implemented only if fluorescein staining
• Engorgement of episcleral vessels for a histologic diagnosis is warranted. has ruled out corneal ulceration:
• Typically bilateral, mildly elevated, red lesions • Topical corticosteroids (e.g., 0.1% dexa-
in the anterior sclera Differential Diagnosis methasone solution or ointment or 1%
• Peripheral corneal vascularization and edema • Nodular episcleritis; other pinkish, raised prednisolone acetate) q 6-8h for 2-3 weeks,
• Nongranulomatous anterior uveitis (p. 1023) lesions then gradually tapered

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