Allergic Eye Disease
Allergic eye disease, or ocular allergy, most commonly manifests as allergic conjunctivitis. The conjunctiva is the transparent lining which covers the white of the eye and the undersurface of the eyelids. Conjunctivitis means inflammation of the conjunctiva. Inflammation of the conjunctiva due to allergy is allergic conjunctivitis.
Inflammation of the conjunctiva can be due to other causes, for example bacteria causing bacterial conjunctivitis. Bacterial conjunctivitis is contagious, whilst allergic conjunctivitis is not.
There are 5 main types of ocular allergy:
Seasonal allergic conjunctivitis (SAC)
allergic conjunctivitis which only occurs in spring and summertime, during the hayfever season.
Perennial allergic conjunctivitis (PAC)
allergic conjunctivitis which occurs all year round, and is most commonly due to dust mite allergy or pet dander allergy.
Vernal keratoconjunctivitis (VKC)
potentially sight-threatening allergic keratoconjunctivitis which occurs in children aged 5-15 years old, and is worst during spring and summertime.
Atopic keratoconjunctivitis (AKC)
potentially sight-threatening allergic keratoconjunctivitis which occurs in adults with skin eczema or those who had vernal keratoconjunctivitis in childhood.
Giant papillary conjunctivitis (GPC)
allergic conjunctivitis under the upper eyelid which is due to a foreign body in the eye such as a contact lens or protruding suture.
What are the symptoms of allergic eye disease?
- Itchy eyeballs with a tendency to rub the eyes
- Watery red gritty eyes
- Stringy mucous discharge
- Sensitivity to light
- Eyelid swelling/ puffiness
Many people with allergic eye disease also have dry eyes and blepharitis. Contacting us for an expert evaluation by Miss Saw is the best way to determine what exactly is causing your symptoms.
The following information is provided as a guide only. Careful assessment and treatment by an eye specialist (ophthalmologist) or eye health professional who has the expert training and experience to accurately determine your diagnosis and best treatment approach is important.
Can I find out what is causing the allergy in my eyes?
Unless the allergy is due to an easily removable cause like a glaucoma eye drop, or wearing a contact lens or a protruding suture, it can be difficult to identify exactly which allergen(s) are causing the problem in allergic eye disease.
Identifying definite lifestyle changes which occurred immediately before the onset of the ocular allergy can help, for example moving home to a carpeted floor instead of wooden floorboards, suggests house dust mite allergy.
Previous studies indicate that skin prick testing results do not accurately correlate in allergic conjunctivitis, so it is not currently recommended.
However if a patient wishes nevertheless to identify which agents or eye make up they may be allergic to, referral to a consultant expert in skin prick testing is possible.
How is allergic eye disease treated?
First, avoid the allergen where possible
Use a vacuum with a HEPA filter to reduce dust in your home, try keeping pets out of the bedroom to reduce dander exposure.
If pollen and seasonal allergens are the cause, sunglasses and a wide brim hat can reduce the amount of allergen that lands in the eyes, and saline eye drops to wash away the allergens can help.
If you use contact lenses, in general, do not wear lenses until symptoms have gone, however you may be advised by your eye specialist if you can wear contact lenses with certain types of eye drops.
Try not to rub your eyes, as this causes more inflammation. Use an artificial tear drop to wash away the itchy feeling whenever possible, rather than rubbing the eyes.
Try not to “fish” out mucus from the eyes, as this causes more mucus to be produced. Use an artificial tear drop to cleanse the mucus away.
Cool compresses with a towel or flannel soaked in cold water can help.
For short-term (for 2 or 3 months) relief of itchy red eye symptoms:
- over-the-counter anti-histamine tablets (e.g. cetirizine, loratadine) and
- over-the-counter mast cell stabilizer eye drops containing sodium cromoglycate 2%, 1 drop 2-4x/day, can help.
Long term intake of oral anti-histamine tablets (for more than 2 months continuously) can lead to dry eye due to reduced watery (aqueous) tear production.
Sodium cromoglycate eye drops are available preservative-free and these can be used with contact lenses in place. Preserved sodium cromoglycate eye drops in a bottle can be used morning and night in contact lens wearers, before inserting and after removing contact lenses each day.
Over the counter anti-histamine eye drops often contain a vasoconstrictor which makes the eyes white (e.g. antazoline antihistamine + xylometazoline vasoconstrictor). There is no problem using these for 1 or 2 days, for example for photographs for a special occasion. However it is not recommended to use eye drops containing vasoconstrictor continuously for more than 1 week, because rebound redness of the eyes will occur when the vasoconstrictor is stopped.
Combined mast cell stabilizer- antihistamine eye drops such as Olopatadine or Ketotifen are very effective for itch and redness due to allergy. They can be used safely all year round if necessary. These must be prescribed by a doctor.
Olopatadine can be used morning and night in contact lens wearers if prescribed by your eye specialist, before inserting and after removing contact lenses each day.
Other mast – cell stabilizing eye drops which may be prescribed by your eye specialist include nedocromil and lodoxamide.
Corticosteroid eye drops
may be required for more severe inflammation and mucus discharge. Steroid eye drops are most commonly used 1-4x/day. Steroid eye drops are associated with development of glaucoma (high intra-ocular pressure), cataracts and infection, so only using the minimum amount of corticosteroid necessary to treat the redness and improve comfort is the goal.
Ciclosporin eye drops
For chronic inflammation due to allergic eye disease, Ciclosporin eye drops may be indicated. They reduce inflammation safely, without causing the side effects associated with steroid eye drops. They have a slow onset of action and the eye drops sting during approximately the first month of use.
For puffy redness of the eyelid skin, steroid creams may be prescribed by Miss Saw. These must be used sparingly and for limited periods, because they can make the skin of the eyelids thin and can cause high intraocular pressure. Inflammation frequently returns when steroid cream is stopped.
If the eyelid skin has chronic recurrent eczema, topical anti-inflammatory cream such as pimecrolimus or tacrolimus 0.03% or 0.1%, which does not have the side effects of steroids, may be prescribed.
Oral corticosteroids or local corticosteroid injection
Oral corticosteroids or local corticosteroid injection in the eyelids may be required in some severe cases of allergic eye disease. Corticosteroids are only used for limited periods of time to rapidly control inflammation. This is in order to minimise the side effects of long term corticosteroids (Cushing’s syndrome, infection, bone thinning, thin skin with easy bruising).
For patients with severe eye inflammation and severe skin eczema, systemic immunosuppression with ciclosporin, tacrolimus or mycophenolate may be indicated. This must only be commenced by a specialist who is expert in systemic immunosuppression, and in collaboration with the patient’s dermatologist.
Immunotherapy (allergy shots)
Immunotherapy (allergy shots) can help in some people. It is mainly available for hay fever sufferers, to provide long-term resistance to triggering allergens.
What is the long term disease course in Allergic Eye Disease?
Perennial and Seasonal allergic conjunctivitis are not sight-threatening conditions. Like hayfever, they may be present for the rest of one’s life.
Most children grow out of vernal keratoconjunctivitis once they are in their 20s. The vernal children who continue to have active chronic allergic eye disease after the age of 20 are then called atopic keratoconjunctivitis.
Can I go blind?
Perennial and seasonal allergic conjunctivitis themselves are not sight-threatening conditions. Vernal and atopic keratoconjunctivitis are potentially sight-threatening and often require treatment with topical and/or oral steroids and immunosuppressive therapy. Both vernal and atopic keratoconjunctivitis can cause permanent scarring of the cornea, the clear front window of the eye, and damage to limbal stem cells.
Keratoconus is often associated with allergic eye disease (SAC, PAC, VKC, AKC). Avoiding eye-rubbing is thought to be important, to prevent the development or worsening of keratoconus. See “Keratoconus”.
Atopic keratoconjunctivitis is also associated with reduced immunity against Herpes simplex infection and Staph infection. Herpes simplex affecting the cornea can lead to permanent scarring of the cornea and blindness.