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Vernal Keratoconjunctivitis (VKC) - From Basics to Clinical

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1. Definition and Overview

• Predominantly affects boys (M:F ratio ~3:1)
• Onset typically from age 5 years onward
• Spontaneous remission in ~95% by late teens; the remainder may transition to atopic keratoconjunctivitis (AKC)
• More prevalent in warm, dry climates: Mediterranean, sub-Saharan Africa, Middle East
• In temperate regions, >90% of patients have co-existing atopic disease (asthma, eczema) and two-thirds have a family history of atopy

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2. Pathogenesis / Immunology

• Histamine - itch, vasodilation
• Eosinophil-derived toxins (MBP, ECP) - epithelial damage, Trantas dots
• IgE - immediate hypersensitivity
• Mast cell mediators - mucus hypersecretion, chemotaxis
• TGF-β, fibroblast growth factor - subepithelial fibrosis

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3. Classification

3a. Palpebral (Tarsal) VKC

• Primarily involves the upper tarsal conjunctiva
• More prone to corneal complications due to close mechanical contact between inflamed tarsal conjunctiva and corneal epithelium

3b. Limbal VKC

• Affects the limbus (corneoscleral junction)
• Typically seen in Black and Asian patients
• Characterized by gelatinous limbal papillae with Horner-Trantas dots

3c. Mixed VKC

• Features of both palpebral and limbal forms

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4. Clinical Features

Symptoms

• Intense itching - the cardinal symptom
• Lacrimation, photophobia, foreign body sensation, burning
• Thick, ropy/stringy mucoid discharge (characteristic)
• Increased blinking; nocturnal rubbing worsens disease

Signs - Palpebral Disease

• Conjunctival hyperemia
• Diffuse velvety papillary hypertrophy on the superior tarsal plate

• Flat-topped, polygonal "cobblestone" appearance
• May have focal or diffuse whitish inflammatory infiltrates

• Form when adjacent macropapillae coalesce as dividing septa rupture
• Mucus deposition between papillae is common in intense disease

Signs - Limbal Disease

• Gelatinous limbal papillae - raised, translucent swellings at the limbus
• Horner-Trantas dots - white/chalky dots at the apex of limbal papillae, composed of degenerated eosinophils and epithelial debris

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5. Corneal Complications (Keratopathy)

Additional complications:

• Predisposition to secondary bacterial and fungal infections
• Aggressive herpes simplex keratitis (possibly steroid-related)
• Keratoconus - occurs in ~15% of VKC patients; thought to be secondary to chronic eye rubbing
• Presenile anterior or posterior subcapsular cataract (may be disease-related or steroid-induced)
• Retinal detachment risk is higher than the general population

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6. Palpebral VKC vs Limbal VKC - Summary

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7. Diagnosis

• Conjunctival scraping - eosinophilia (eosinophils abundant) is confirmatory
• Tear IgE levels elevated
• Total serum IgE may be elevated
• Skin prick tests / allergen-specific IgE (RAST) - identify triggering allergens in atopic cases

• Giant papillae on eversion of upper lid (mandatory step)
• Horner-Trantas dots at limbus
• Shield ulcer / corneal plaque superiorly
• Thick ropy mucus in fornix

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8. Differential Diagnosis

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9. Treatment

General Measures

• Allergen avoidance where possible
• Cool compresses - symptomatic relief
• Avoid eye rubbing - reduces keratoconus risk
• Lid hygiene for associated staphylococcal blepharitis
• Bandage contact lens for persistent epithelial defects

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Step-Up Pharmacological Approach

Step 1 - Mast Cell Stabilizers (First-line, prophylactic)

• Sodium cromoglicate, nedocromil, lodoxamide (most potent), pemirolast
• Require several days to weeks for effect; used prophylactically 2-3 weeks before season
• Lodoxamide 0.1% QID
• Seldom effective in isolation during acute flares

Step 2 - Dual-Action Antihistamine/Mast-Cell Stabilizers (Preferred for active disease)

• Olopatadine 0.1% BD or 0.2%/0.7% once daily
• Alcaftadine 0.25% once daily
• Ketotifen 0.1% BD
• Best for both prophylaxis and acute symptom control

Step 3 - Topical Steroids (For moderate-severe or acute exacerbations)

• Prednisolone acetate 1%, loteprednol 0.5%, dexamethasone 0.1%
• Use short courses only; always monitor IOP
• Steroid-induced glaucoma and cataract are significant risks with prolonged use

Step 4 - Immunomodulators (Steroid-sparing)

• Cyclosporin A 0.05-2% eyedrops 2-6x daily - effective when steroids are inadequate or poorly tolerated; takes weeks to work
• Verkazia (cyclosporin 0.1% cationic emulsion) - licensed specifically for VKC in children ≥4 years, QID
• Tacrolimus 0.1% ointment - effective for shield ulcers and eyelid disease; useful without steroids

Step 5 - Supratarsal Steroid Injection

• For severe palpebral disease or non-compliant patients
• 0.1 ml betamethasone/dexamethasone/triamcinolone injected under the upper eyelid via everted conjunctival surface

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Systemic Treatment

• Oral antihistamines (e.g., loratadine - non-sedating; diphenhydramine - sedating, useful at night to reduce nocturnal rubbing)
• Aspirin has shown benefit in VKC - but avoid in children/adolescents due to Reye syndrome risk
• Doxycycline / azithromycin - for blepharitis-aggravated disease
• Immunosuppressives (cyclosporin, tacrolimus, azathioprine) for refractory cases
• Allergen desensitization
• Plasmapheresis in patients with extremely high serum IgE

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Mucolytic Therapy

• Acetylcysteine eye drops - dissolves mucus filaments and deposits; useful for plaque prevention/management

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10. Management of Shield Ulcer

1. Topical steroid (prednisolone acetate 1% or loteprednol 0.5%) 4-6x/day
2. Topical antibiotic (trimethoprim/polymyxin B QID) - prophylaxis against secondary infection
3. Mast cell stabilizer/antihistamine continued
4. Bandage contact lens if healing is delayed
5. Acetylcysteine for mucous plaque
6. Tacrolimus 0.1% ointment - effective alternative to steroids
7. Surgical debridement (superficial keratectomy) if plaque prevents re-epithelialization
   • Excimer laser phototherapeutic keratectomy (PTK) is an alternative

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11. Surgical Options

• Superficial keratectomy - removes corneal plaques; debrides shield ulcers
• Excimer laser PTK - alternative to mechanical keratectomy
• Amniotic membrane overlay grafting - surface restoration
• Lamellar keratoplasty - for severe corneal scarring
• Botulinum toxin-induced ptosis - to reduce mechanical trauma from lid on cornea in refractory cases

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12. Prognosis and Follow-up

• Spontaneous remission in ~95% by late teens - VKC is largely a self-limiting disease
• Remaining 5% may progress to AKC (perennial, more severe, adult)
• Corneal scarring from shield ulcers or plaques can cause permanent visual impairment
• Keratoconus risk (~15%) warrants periodic corneal topography
• If topical steroids used: monitor IOP every 4-6 weeks
• Follow-up: Every 2 weeks during acute flares; less frequent in remission

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Quick Clinical Summary Card

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