Allergic conjunctivitis is caused by reactions to allergens in the environment. It causes inflammation to the conjunctiva (the thin layer that lines the white part of the eye and the inside of the eyelid) causing the eye to turn pink and itchy. The allergens include pollen or animals, swimming pool chlorine, vehicle fumes, cigarette smoke or other toxic substances.
Allergic conjunctivitis is common among people with seasonal allergies. It also affects those with asthma, hay fever and eczema. Allergic conjunctivitis is not contagious. A foreign body in the eye can cause an allergy (giant papillary conjunctivitis).
- Seasonal allergic conjunctivitis (SAC) - The most common type caused by airborne allergens like grass, molds, trees and weed pollen.
- Perennial allergic conjunctivitis (PAC) - A more persistent type which can go on throughout the year. It is usually triggered by animal dander (flecks or loose scales), molds and dust mites.
Causes and Risk Factors
Allergic conjunctivitis is caused by the body’s reaction to certain allergic substances. These include:
- Pollen from plants, weeds, trees and grasses
- Dust mites
- Dander from pets
- Contact lenses and lens solution
Giant papillary conjunctivitis is caused by a foreign body in the eye. It is prevalent among people who wear hard or rigid contact lenses. It also affects those who do not replace their soft contact lenses regularly. It may manifest in those who have an exposed suture on the surface of the eye or have a prosthetic eye.
Signs & Symptoms
People with allergic conjunctivitis will exhibit the following symptoms:
- Occurrence in both eyes
- Red or pink color in the white of the eye
- Intense itching
- Sneezing, asthma, a tickly nose and an irritated throat
- Swelling of the conjunctiva and eyelids
- Watery eyes
- A gritty sensation in the eye or feeling like there is something in the eye
- Irritation and burning
- Runny or itchy nose
The eye professional will conduct a comprehensive eye examination to determine the type of conjunctivitis. A laboratory testing may also be necessary. This is because it is difficult to make an accurate diagnosis. Often, the symptoms of the various conjunctivitis types are the same. The following may follow:
- Examine a patient's history and symptoms to determine when the symptoms began. He/she will also seek to determine if other general health or environmental conditions are affecting the problem.
- Evaluate the eye’s inner structures to ensure no other tissues have been affected by the condition
- Measure visual acuity to check if vision has been affected
- Conduct laboratory testing by collecting cultures or smears of conjunctival tissue. This is done when the eye is not responding to medical treatment
Treatment towards allergic conjunctivitis is aimed at increasing patient comfort. It is also supposed to lessen the course of inflammation.
Allergic conjunctivitis usually goes away on its own when the allergen is removed from the individual’s environment. In severe cases, the eye doctor may prescribe nonsteroidal anti-inflammatory medications and antihistamines. People with persistent allergic conjunctivitis can also use topical steroid eye drops. Further, lubricating eye drops can rinse the allergen off the surface of the eye. Individuals with allergic conjunctivitis should not use red reducing eye drops such as Visine since they can worsen the symptoms.
For further relief and comfort, an individual can use cold compresses and artificial tears. These can be acquired over the counter. The compress can be put on the eye three to four times a day. Practicing good hygiene is the best home treatment. The following can also help in quick recovery and avoiding re-infection:
Keep the eye clean by using a clean cotton ball or paper towel
Thoroughly wash the hands with soap and warm water
Avoid rubbing the eye
Avoid touching the infected eye with bare hands. Clean tissue is better preferred
- Keep the surrounding (laundry, bed, pillow cases, etc.) clean
- Avoid sharing things like makeup, eye drops or contact lenses
- Discard eye makeup especially mascara
- Avoid contact lenses while the eye is infected. The ophthalmologist will advise about contact lenses
- Use the eye drops as instructed. There should be no extended use of the eye drops
- If only one eye is affected, the person should not use the same bottle of drops in the uninfected eye
Usually, allergic conjunctivitis will clear on its own within one to two weeks; especially after the allergen has been removed from the environment. The eye also improves significantly with medication. There are usually no lasting problems with the eye. Mild cases of the condition are quite harmless and get better without treatment.
For severe cases, the physician may have the patient return after a few days. This is to ensure that the eye is improving with the prescribed medication.
Because allergens cause allergic conjunctivitis, it is advisable to keep away from substances or animals that may cause allergic reactions.