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Allergic conjunctivitis is the inflammation of the conjunctiva due to allergy. It occurs due to the exposure to an allergen. Conjunctiva is the mucous membrane that lines the eyelids. It is very susceptible to allergens. Therefore, the reaction is quick and spontaneous when it comes in contact with an allergen.
What Causes Allergic Conjunctivitis?
When there is an exposure to allergen, considering it as an antigen, the immune system is activated. Then the body produces an antibody called immunoglobulin E (IgE). IgE then binds to the mast cells leading to production of inflammatory mediators such as histamines. These inflammatory mediators lead to allergic symptoms. Allergic conjunctivitis can be of different types based on the underlying cause:
- Simple Allergic Conjunctivitis: It is caused by exposure to eye medications, contact lens solutions, or allergens such as pollen, dust, smoke, or animal dander.
- • Hay fever conjunctivitis: It is commonly associated with allergic rhinitis. Common allergens such as pollen, or animal dander cause this condition.
- • Seasonal allergic conjunctivitis: It is caused by exposure to seasonal allergens such as pollen.
- • Perennial allergic conjunctivitis: It is caused by continuous exposure to persistent allergens such as house dust mites, cosmetics, and smoke.
- Vernal Keratoconjunctivitis: It occurs due to exposure to severe hot conditions. It occurs mostly in men.
- Giant Papillary Conjunctivitis: It occurs due to trauma caused by contact lens or post-operative sutures.
- Atopic Keratoconjunctivitis: It occurs in patients with atopic dermatitis.
- Contact Dermoconjunctivitis: It occurs due to prolonged exposure to chemicals and medications such as atropine, penicillin, or neomycin.
Symptoms of Allergic Conjunctivitis:
Allergic conjunctivitis can be unilateral or bilateral. Symptoms of allergic conjunctivitis are:
- • Itching
- • Redness
- • Burning sensation
- • Mild photophobia or sensitivity to light
- • Watery discharge from eyes
- • Swelling of the eyelids
- • Sneezing
- • Sore throat
Risk Factors of Allergic Conjunctivitis:
Exposure to allergens or history of allergies is the major factor for allergic conjunctivitis. Other factors that may increase the risk of allergic conjunctivitis are:
- • History of asthma, eczema, or hay fever
- • Use of contact lens and not cleaning them properly
- • Exposure to patient with allergic conjunctivitis
- • Poor personal hygiene
- • Exposure to certain viruses or bacteria
- • Use of cosmetics
Complications of Allergic Conjunctivitis:
Complications with allergic conjunctivitis are very rare. However, if left untreated, this condition may lead to corneal ulceration. Corneal ulceration is an inflammatory condition of cornea in which there is an open sore on it.
Diagnosis of Allergic Conjunctivitis:
Usually, allergic conjunctivitis is diagnosed based on the symptoms and medical history. The healthcare provider may ask about recent exposure to the allergen. Questions can be about duration of the allergy, previous history of allergy, pattern of occurrence, effect on vision, and pain or discharge from the eye.
Signs and symptoms such as swollen blood vessels, redness, and photophobia can be assessed using a slit-lamp microscope.
Diagnostic tests are rarely recommended. A blood test can be performed to determine eosinophil count as its count increases during allergies. IgE antibody levels can also be measured as these levels increase.
Treatments for Allergic Conjunctivitis:
The treatment for allergic conjunctivitis focuses on treating the symptoms and reducing the complications. Treatment includes nonmedical and medical management.
Nonmedical Management:
- Cold Compress: Applying an ice pack on the eye can help to reduce redness and swelling.
Medical Management:
- Antihistamines: These drugs antagonize the action of histamines. They can be given orally or topically. These are considered to be effective medication for allergic conjunctivitis. Examples of topical antihistamines are azelastine and epinistine and oral antihistamines are cetrizine and fexofenadine.
- Vasoconstrictors are available in combinations such as naphazoline-antazoline and naphazoline-pheniramine
- Mast Cell Stabilizers: They are used alone or in combination with antihistamines. Examples are sodium cromoglycate and lodaximide.
- Leukotriene Receptor Antagonists act against leukotrienes (type of inflammatory mediators). Examples include monteleukast and zafirlukast.
- Corticosteroids: These drugs are given in serious cases and used only for short duration as long-term use can cause potential side-effects.
- Topical Nonsteroidal Anti-Inflammatory Agents (NSAIDs): These drugs help to reduce itching and infection.
- Immunosuppressants such as cyclosporine can be given in steroid resistant cases.
As eye drops are prescribed for the treatment, it is necessary to know the proper way to instill eye drops. Steps to instill eye drops are:
- • Sit or lie down and tilt your head backwards.
- • Then, gently pull the lower lid with the index finger.
- • Place one eye drop (drops as prescribed) into the lower eyelid with the help of the dropper.
- • Then remove the finger from the eyelid and close the eye for few minutes.
Prevention of Allergic Conjunctivitis:
Avoiding the exposure to the allergen is the primary measure to prevent allergic conjunctivitis. Other measures are:
- • Avoid rubbing your eyes.
- • Minimize the house dust by cleaning the carpets, curtains, and bedding regularly.
- • Be in cooler climate.
- • Avoid use of contact lens.
- • Cover windows with screens to avoid entry of pollen into the house.
- • Close windows when the pollen is high.
- • Avoid chemical exposure to eyes.