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Allergic conjunctivitis is the inflammation of the membrane covering the white part of the eye (conjunctiva) due to allergy. The most common form of allergic conjunctivitis is seasonal allergic conjunctivitis, which accounts for approximately 98% of ocular allergies.
Symptoms of allergic conjunctivitis include itching, redness, eyelid swelling, tearing and nasal symptoms. Sufferers with allergic conjunctivitis will experience intense itching of the eyes, with a stringy discharge and eyes are often intermittently red.
Allergic conjunctivitis is not contagious, but is caused by common allergens such as pollen, grass, mold, dust mites, perfumes, cosmetics, skin medications, air pollutions and smoke. Allergic conjunctivitis is common in people who have allergic disorders such as hay fever, asthma and eczema.
It usually affects both eyes at the same time although it may start in one eye and spread to the other eye after a day or two.
6 million suffer
It is estimated that about six million South Africans suffer from allergies to pollen. Pollen profiles may be typical of Mediterranean, subtropical, savannah, grassland, semi-desert and arid regions, many of which are characteristic of South Africa’s biodiversity in climatic conditions. Furthermore, South Africa is home to 957 of the known grass species worldwide.
People living in the Highveld of South Africa are particularly prone to this condition. Seasons also affect sufferers considerably, with spring often being a particularly difficult time. This is due to the increased amount of pollen being released by trees, grass and flowers.
Pollen levels are usually highest mid-morning, and larger amounts are present on hot windy days. During hot, humid weather, especially after thunderstorms, pollen grains tend to rupture, releasing fine granules into the air. Allergic conjunctivitis caused by these types of allergens tends to improve in cool, rainy weather.
It is interesting to note that the incidence of allergic conjunctivitis in rural African populations is less common, but increases in those rural populations which move to semi-urban areas and adopt a more Western standard of living.
Why the increase?
Some reasons sited for the increased level of allergies worldwide include that since children in more affluent countries are leading “cleaner” lives, their immune systems have less exposure to parasites and pathogens than children may have had a decade earlier.
An exaggerated response can then be experienced, such as an allergic reaction. Another theory is the exponential use and over-use of chemicals in certain nations since the Second World War, as well as the subsequent decreasing quality of the air around us.
Some medical practitioners view the increase in allergies as a negative consequence of the use and over use of antibiotics and vaccines.
Anyone can get it
Allergies such as allergic conjunctivitis occur across the age, gender and race spectrum, and can start at any age. Allergic conjunctivitis is, however, seen predominantly as a disease of young adults, between the ages of 17 and 37, with an onset of symptoms typically at about age 20.
This type of ocular allergy is more widespread in boys before the age of 15, with seasonal allergic conjunctivitis having a slightly higher prevalence in males overall.
Heredity is another risk factor, with children of one allergic parent, running an increased risk of between 30 and 50 % of inheriting a similar allergy, although the type of allergy may vary. If both parents have allergies, this risk rate increases to between 60 and 80%.
There is also no indication that children outgrow the tendency to be allergic.
Prevention
Allergic conjunctivitis can, to some degree, be avoided, or lessened; by staying indoors when the pollen and mold levels are high (high allergen levels are often disclosed during weather reports). Keeping doors and windows closed and using an air conditioner during summer might also help.
The use of contact lenses while suffering from allergic conjunctivitis is also not recommended. Good hygiene of face and hands is also very important, and sufferers should try and avoid rubbing of the eyes.
Because there are many levels of ocular allergic reactions, management is primarily aimed at reducing symptoms. The most effective treatment for allergic conjunctivitis is to eliminate the potentially offending allergen, although this is not usually possible.
Several types of eye drops or topical antihistamines are available to treat allergic conjunctivitis. These will help to relieve itchy, watery eyes and may keep symptoms from returning.
Vernal allergic conjunctivitis
Prof Trevor Carmichael of Johannesburg General Hospital says that a specific type of allergic conjunctivitis, called Vernal allergic conjunctivitis, is seen commonly in children in South Africa.
It affects African children more often, giving rise to ‘muddy’ looking eyes due to increased pigmentation over the white of the eye. As with other allergic conjunctivitis, it causes the child to rub the eyes and this may be disruptive to their schooling.
They should use eye drops prescribed by the doctor to prevent itching. Eventually they often ‘outgrow’ this form of the disease when in their teens. Rarely, the cornea can be affected causing vision loss.
South African studies reinforce international figures which suggest that allergies have doubled worldwide over the last 10 to 15 years. The increase affects all race groups and social classes. As society becomes more sophisticated, allergies seem to be increasing. They are a disease of modern living.
(Alcon Laboratories, October 2007)
