Conjunctivitis refers to inflammation of the conjunctiva which is the thin transparent membrane that protects the white portion of the eyes and also lines the inside of the eyelids. It has thin blood vessels that are normally not visible. However, when inflamed due to allergy these vessels become prominent and the conjunctiva appears red.
Common allergens include dust, pollen or smoke. Most eye allergies can be treated by over the counter medications but some cases may need additional treatment.
What are the Types of Eye Allergies?The types of allergic conjunctivitis include the following -
Seasonal allergic conjunctivitis or allergic rhinoconjunctivitis
- Seasonal allergic conjunctivitis is also known as hay fever
- The allergen most commonly responsible is pollen
- Symptoms occur usually in spring and summer when the plants, grass and flowers are rich in pollen
- Symptoms include sneezing, blocked or runny nose, itchy and watery eyes
- Also termed contact dermatoconjunctivitis
- Caused by chemicals or cosmetics that irritate the eye
- Allergic response results in redness, burning and watery eyes
- Symptoms typically occur 2-4 days after contact with allergen
- It is not common and seen in persons who wear contact lenses that irritate and cause discomfort
- Affects the conjunctiva lining the inner part of upper eyelid
- Also seen in persons who use hard contact lenses following eye surgery
- Eyes become red and teary
- Poor hygiene while handling contact lenses or contact lens fluid or the contact lens case can lead to superimposed bacterial infection
- Occurs throughout the year
- Main allergen responsible is house dust mite found in beddings, furniture upholstery and carpets
- Symptoms include sneezing, runny nose and eyes that may be worse on waking in the morning
- Other allergens are animal hair, fur, and bird feathers
What are the Causes of Eye Allergies?
- Cosmetics and eye drops
- House dust mite
- Animal fur or hair
- Food allergy may sometimes cause eye symptoms
- Associated with asthma or eczema
Normally, the immune system responds to injurious stimuli such as bacteria and viruses to protect the body. In eye allergy (or any allergy), the immune system mistakenly recognizes the substance as dangerous even though it may be harmless. The immune system causes release of chemicals such as histamine (by cells called mast cells) to destroy the allergen but they also irritate nerve endings with increased secretion of tears and expand blood vessels causing increased blood flow and redness of eyes.
What are the Symptoms and Signs of Eye Allergies?
- Both eyes are usually involved and symptoms evolve fast
- Itchiness and gritty sensation in eyes with burning
- White portion of the eyes appears red or pink
- Rarely painful eyes
- Swollen and puffy eyelids especially on waking
- Increased watering and tearing of eyes
- Vision is normal
- Associated photosensitivity
- In severe cases the conjunctiva lining the upper eyelid becomes swollen and appears Lumpy
How do you Diagnose Eye Allergies?
- A diagnosis of allergic conjunctivitis can usually be made from patient history including occurrence of associated sneezing or runny nose, time of occurrence, triggering factors and duration of symptoms
- Other causes of red eyes must be ruled out from history and eye examination
- Persons with associated asthma or eczema may be helped by seeing an allergy specialist who performs a skin prick test to identify the possible allergen. During a skin prick test small amounts of suspected allergens are introduced via a needle prick into the skin. Appearance of a red, swollen bump means an allergic reaction to that allergen
What are the Complications of Allergic Conjunctivitis?Usually allergic conjunctivitis is not a serious condition and more often causes discomfort rather than anything serious.
Occasionally contact conjunctivitis dermatitis (dermatoconjunctivitis) and conjunctivitis due to contact lens (giant papillary conjunctivitis) may cause inflammation of the cornea (the thin membrane that covers the colored portion of the eye, the iris), also termed keratitis. Keratitis can cause scarring of cornea and vision loss.
How do you Treat and Manage Eye Allergies?General Measures
- Avoid the agent that is causing the allergic conjunctivitis. Keep the beddings and furniture clean and dust regularly. Stay indoors during the pollen season
- Apply eye drops such as artificial tears in the eyes to dilute the allergen and remove it
- Avoid rubbing the eyes as it can make the symptoms worse
- Cold compresses on the eyelid to soothe the burning eyes
- Avoid wearing contact lenses while using eye drops as the preservative in the eye drops can seep into the lens and can itself cause allergy
Seasonal and perennial allergic conjunctivitis
- If symptoms are mild and self-limiting, no treatment may be required
- Eye drops to counter allergic symptoms – Anti-histamine drops (twice a day), mast cell stabilizers e.g. Sodium Cromoglycolate (upto 4 times a day), combination eyedrops containing antihistamine and a vasoconstrictor agent that reduces the blood flow to the site
- Anti-histamine tablets such as loratadine and chlorpheniramine to decrease allergic symptoms
- Steroid eye drops such as betamethasone drops; should only be used under supervision of a doctor and only if other treatments fail
- Steroid tablets – Only short courses of 3-5 days recommended under a doctor’s supervision because of side effects such as weight gain, bone loss and suppression of immunity with long term use
- Avoid wearing contact lenses until symptoms clear completely
- Maintain good lens hygiene or try changing to an alternative type of contact lens
- Eye drops containing antihistamine or mast cell stabilizer may be advised for relief of symptoms
- Identify and avoid the chemical that caused the allergy
- Any form of eye make-up such as mascara should be changed every three months in any case for hygienic reasons
- Change to an alternative brand of cosmetic
- Sometimes the allergy may be caused by eye drops used to treat another condition such as glaucoma or drops for eyelash extension. Discuss with your doctor suitable and safer alternatives
- Antihistamine and mast cell stabilizer containing eye drops do not work in these cases
How can you Prevent Eye Allergies?
- The only way to prevent allergic conjunctivitis is to avoid the allergen
- Avoid house dust mite by not using soft furnishing such as cushions and drapes
- Vacuum the house regularly and use a damp cloth to wipe the dust. Use a vacuum cleaner equipped with a HEPA filter
- Use beddings and mattresses that have low allergy potential Avoid keeping pets if you are allergic to animal hair or fur
- Avoid going out during the pollen season, particularly during the mid-afternoon and early evening when the pollen count is high. Wear protective clothing and sun glasses when going out
- Change your clothes and have a bath after returning from outside
- Avoid mowing the lawn yourself if you are allergic to grass pollen