Allergic conjunctivitis
What is allergic conjunctivitis?
Allergic conjunctivitis is an inflammation of the conjunctiva – the transparent membrane that covers the white of the eye and the inside of the eyelids – caused by an overreaction by the immune system to allergens present in the environment.
Although not contagious or dangerous, it can be very unpleasant and disabling, especially when symptoms recur frequently or are combined with other respiratory allergies such as rhinitis or asthma.
Seasonal allergic conjunctivitis
This occurs at specific times of the year, during pollination. It is usually accompanied by rhinitis and affects both eyes with acute symptoms during spring and summer.
Perennial allergic conjunctivitis
This occurs throughout the year and is caused by allergens such as house dust mites, mould or pets. Its symptoms are usually milder, but persistent.
What causes it?
The most common triggers for allergic conjunctivitis are allergens that come into contact with the eyes through the air:
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Pollen (from trees, grasses or weeds)
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House dust mites
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Animal epithelia (dogs, cats, horses, etc.)
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Mould spores
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Environmental pollution
Occasionally, certain cosmetics, cleaning products or contact lenses may also cause symptoms if the patient is allergic to their components.
Most common symptoms
Allergic conjunctivitis usually affects both eyes symmetrically. The most common symptoms are:
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Intense, sometimes uncontrollable itching, made worse by rubbing the eyes.
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Constant tearing, with no apparent emotional cause.
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A gritty or stinging sensation in the eye, which causes continuous discomfort.
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Visible redness, especially in the white of the eye (sclera).
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Swollen eyelids, especially in the morning.
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Photophobia (sensitivity to bright light), in some cases.
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Mild mucous discharge, with no pus or signs of infection.
Who does it affect?
Allergic conjunctivitis can occur at any age, although it is especially common in children, adolescents and young adults with a personal or family history of allergies. In many cases, it occurs in conjunction with allergic rhinitis (what is known as rhinoconjunctivitis syndrome), and can recur at the same time every year.
Treatments for allergic conjunctivitis
Treatment aims to relieve symptoms, reduce eye inflammation and prevent recurrences:
1. Avoid contact with the allergen.
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Avoid rubbing your eyes (this may worsen inflammation).
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Keep windows closed on days with a high pollen count.
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Wear sunglasses outdoors.
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Change your clothes and wash your face after being outdoors.
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Avoid contact with pets if an allergy to epithelia is suspected.
2. Pharmacological treatment
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Artificial tears to wash and soothe the eyes.
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Topical antihistamines (eye drops): quickly relieve itching.
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Mast cell stabilisers (preventive): reduce allergic reactions if used continuously.
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Topical corticosteroids: reserved for severe cases and under medical supervision.
3. Specific immunotherapy (vaccines)
If conjunctivitis recurs every year and seriously affects quality of life, the specialist may recommend immunotherapy to desensitise the body to the allergen that is causing it.
Handy tips for people with allergic conjunctivitis
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Use cold compresses over your eyes to relieve itching.
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Avoid environments that are smoky or have very dry air.
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Do not share towels or eye cosmetics.
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Wash your hands often.
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Always consult your doctor before using eye drops.
