Allergic Conjunctivitis

Allergic conjunctivitis is an inflammation of the conjunctiva (the thin membrane covering the white part of the eye and the inner eyelids) caused by an allergic reaction to environmental allergens. It is a common condition affecting people of all ages, especially those with a history of allergies. 

Causes of Allergic Conjunctivitis

Allergic conjunctivitis occurs when the immune system over-reacts to allergens, triggering an inflammatory response. Common allergens that cause this condition include:

• Pollen (seasonal allergic conjunctivitis, or hay fever conjunctivitis)

• Dust mites

• Pet dander

• Mould spores

• Smoke and air pollution

• Cosmetic products

• Certain medications or eye drops

Types of Allergic Conjunctivitis

1. Seasonal Allergic Conjunctivitis (SAC): Most common in spring and autumn, caused by pollen from trees, grass, or weeds.
   

2. Perennial Allergic Conjunctivitis (PAC): Occurs year-round due to indoor allergens like dust mites and pet dander.
   

3. Giant Papillary Conjunctivitis (GPC): Often seen in contact lens wearers due to chronic irritation.
   

4. Vernal Keratoconjunctivitis (VKC): A severe form affecting young boys, often during warm months.
   

5. Atopic Keratoconjunctivitis (AKC): Chronic and severe, associated with atopic dermatitis and often affecting older adults.

Symptoms of Allergic Conjunctivitis

The symptoms of allergic conjunctivitis can range from mild to severe and may include:

• Redness in the eyes

• Itching (the most common symptom)

• Watery or teary eyes

• Swelling of the eyelids

• Burning or irritation

• Sensitivity to light (photophobia)

• Stringy mucus discharge

• Dryness in the eyes

Diagnosis of Allergic Conjunctivitis

Diagnosis is typically based on a patient's medical history, symptoms, and an eye examination. Additional tests may include:

• Allergy testing: Skin prick or blood tests to identify specific allergens.
  

• Conjunctival scraping: To examine for eosinophils, a type of white blood cell associated with allergies.
  

• Tear film analysis: To detect allergic markers in tears.

Treatment of Allergic Conjunctivitis

1. Avoidance of Allergens

• Stay indoors during high pollen seasons.

• Use air purifiers and keep windows closed.

• Wash hands and face after exposure to allergens.

• Change bed linens frequently to minimise dust mites.

• Avoid rubbing the eyes to prevent worsening symptoms.

2. Medications

• Antihistamines: Oral (e.g., cetirizine, loratadine) or topical (e.g., ketotifen, olopatadine) to reduce allergic reactions.

• Mast Cell Stabilisers: Eye drops like cromolyn sodium to prevent histamine release.

• Decongestants: Short-term use of drops like naphazoline to reduce redness.

• Non-Steroidal Anti-Inflammatory Drugs (NSAIDs): Such as ketorolac for inflammation relief.

• Corticosteroids: For severe cases, prescribed under medical supervision.

3. Home Remedies and Lifestyle Changes

• Applying a cold compress to reduce swelling and itching.

• Using preservative-free artificial tears to wash out allergens.

• Wearing sunglasses outdoors to protect from airborne allergens.

• Maintaining good hygiene to prevent secondary infections

Complications of Allergic Conjunctivitis

While allergic conjunctivitis is not life-threatening, untreated severe cases can lead to:

• Chronic eye inflammation

• Corneal damage (in VKC and AKC)

• Secondary bacterial infections

• Vision problems in extreme cases

When to See a Doctor

Consult an eye specialist if:

• Symptoms persist despite home treatment.

• Vision changes occur.

• Severe pain or discharge is present.

• Over-the-counter medications do not provide relief.

In Summary

Allergic conjunctivitis is a common eye condition triggered by allergens, leading to itching, redness, and discomfort. Proper diagnosis and treatment, including allergen avoidance, medications, and home remedies, can help manage symptoms effectively. If symptoms worsen or persist, professional medical advice should be sought to prevent complications and ensure optimal eye health.