Allergic Conjunctivitis

Allergic Conjunctivitis

🌸 Allergic Conjunctivitis

🔍 Definition

Allergic conjunctivitis is inflammation of the conjunctiva caused by an allergic reaction to environmental allergens. It's a non-infectious, immune-mediated response, often affecting both eyes.

🚨 Causes / Triggers

Pollen (grass, trees, weeds – seasonal)
Dust mites
Animal dander
Mold
Contact lenses or solutions
Air pollutants, smoke

🧠 Pathophysiology (Quick!)

Allergen exposure triggers IgE-mediated hypersensitivity
Mast cells in the conjunctiva release histamine, prostaglandins, and other inflammatory mediators
Leads to vasodilation, increased tear production, and itching

👁️ Symptoms

Symptom	Notes
Itching	Main feature – often severe
Redness	Bilateral and diffuse
Tearing (epiphora)	Clear, watery discharge
Burning or gritty feeling	Not painful, but irritating
Swollen eyelids	Due to inflammation
Photophobia	Mild, in some cases
Ropy, white mucous discharge	Especially in vernal keratoconjunctivitis

🔍 Signs on Examination

Bilateral conjunctival injection (red eyes)
Chemosis (conjunctival swelling)
Papillae on the upper tarsal conjunctiva (especially in vernal type)
Lid edema
No preauricular lymphadenopathy (helps differentiate from viral)

📅 Types of Allergic Conjunctivitis

Type	Description
Seasonal Allergic Conjunctivitis (SAC)	Most common – flares in spring/summer
Perennial Allergic Conjunctivitis (PAC)	Year-round – often from dust, pets
Vernal Keratoconjunctivitis (VKC)	Severe, often in boys, springtime, thick discharge
Atopic Keratoconjunctivitis (AKC)	Severe chronic form, often in adults with eczema

💊 Treatment

Approach	Details
Avoid allergens	Air purifiers, keep windows closed, no pets in bedroom
Cold compresses	Reduces itching and swelling
Artificial tears	Wash out allergens + soothe
Topical antihistamines	e.g. Olopatadine, Ketotifen
Mast cell stabilizers	e.g. Cromolyn sodium (takes days to work)
Dual-action drops	Antihistamine + mast cell stabilizer
Oral antihistamines	For systemic allergy control
Steroid eye drops	Short-term only, under supervision (risk of ↑ IOP, cataract)
Immunomodulators (e.g., cyclosporine)	In chronic or severe cases like VKC/AKC

🧠 Key Clinical Pearls

ITCHING = ALLERGIES until proven otherwise
Typically bilateral
No purulent discharge (differentiates from bacterial)
Improves with antihistamines, worsens in allergy seasons

📋 When to Refer to Ophthalmology

No response to treatment
Severe symptoms (e.g., corneal involvement in VKC/AKC)
Vision changes
Frequent recurrences
Steroid-dependent cases

🧼 Prevention Tips

Shower after being outdoors
Change clothes and bedding frequently
Keep pets out of sleeping areas
Wear sunglasses to block pollen
Avoid rubbing eyes (can worsen symptoms)

🎯 Summary Table

Feature	Allergic Conjunctivitis
Cause	Environmental allergens
Discharge	Watery or ropy, not purulent
Laterality	Usually bilateral
Main symptom	Itching
Contagious?	❌ No
Best treatment	Antihistamine + mast cell stabilizer drops
Steroid use	Short-term only under supervision

Comments