Eye allergies, called allergic conjunctivitis, are a common condition that occurs when the eyes react to something that irritates them (allergen). The eyes produce a substance called histamine to fight the allergen. As a result, the eyelids and conjunctiva – the thin membrane lining the inside of the eyelids and the white part of the eye (sclera) – become red and swollen, producing itching, tearing and burning. Unlike bacterial or viral conjunctivitis, allergic conjunctivitis is not transmitted from person to person. Usually (but not always), people who suffer from eye allergies also suffer from nasal allergies, which are accompanied by nasal congestion, an itchy nose and sneezing. It is usually a temporary (though acute) condition, associated with seasonal allergies. However, in other cases, eye allergies can develop from exposure to environmental irritants, such as pet dander, dust, smoke, perfumes, or even food. If the exposure is continuous, allergies can be more severe, producing significant burning and itching and even light sensitivity.
Symptoms of Eye Allergies
The most common ocular symptoms of allergy are:
- Redness of the eyes, swelling or itching
- Burning or tearing of the eyes
- Light sensitivity
If the eye allergy is accompanied by a nasal allergy, you may experience other symptoms such as nasal congestion, itchy nose and sneezing, as well as headache, itching or sore throat, or cough.
What causes the eye allergies?
An allergy exists when the body’s immune system reacts to something that is normally harmless, called an allergen. When an allergen comes into contact with the eye, certain cells in the eye (called mastocyte or mast cells) release histamine and other substances to combat the allergen. This reaction causes your eyes to turn red, and that they get itchy and teary. Many eye allergies are a response of the body to allergens present in the air – indoors or outside – such as dust, animal dander, mold or smoke. Some of the most common allergens in the air are grass pollen, ragweed pollen, and in general the pollen released from trees, which contribute to the development of seasonal allergies. Allergic reactions to perfumes, cosmetics or medications can also cause the eyes to have an allergic reaction. Some people can be allergic to the chemical preservatives found in lubricant eye drops. These people should use eye drops free of chemical preservatives. Sometimes, the eyes may react to other allergens that do not necessarily come into direct contact with the eye, that are found in some specific type of food or bug bites.
In some cases, eye allergies can be inherited from the parents. Someone is more likely to develop allergies if both parents have them, rather than just one.
Diagnosis of eye allergies
To provide the right treatment, your ophthalmologist will check if your symptoms are related to an eye infection or allergic conjunctivitis. He or she can diagnose allergic conjunctivitis easily through an eye exam and knowing your medical history, including your family history regarding allergies.
Your ophthalmologist will examine your eyes with a slit-lamp microscope to check for signs of ocular allergies, such as swelling of the blood vessels on the surface of the eye.
If your allergies are severe, or if it’s not completely clear that you have allergic conjunctivitis, your ophthalmologist may opt to test for a specific type of white blood cells (called eosinophils) that appear in the areas of the eye where there is a reaction allergic to something. This test is done by gently s.
Treatment for eye allergies
The key to treating eye allergies is to avoid or limit contact with the substance that causes the problem. But you have to know what to avoid. If necessary, an allergist can perform a skin or blood test to help identify specific allergens.
Avoid allergens
If pollen is an allergen to you, avoid going outdoors as much as possible when pollen rates are higher (generally during mid-morning and early in the afternoon) and when the wind blows it lifts pollen. When you are outdoors, wearing glasses or sunglasses can help prevent pollen from entering your eyes.
To help minimize exposure to pollen and other irritants while indoors, keep the windows closed and use air conditioning in both your car and at home. Do not use window fans, as these can bring pollen and other allergens into indoor areas. Keep your air conditioning units clean to avoid allergen cycles in indoor areas.
If mold is an allergen to you, remember that high humidity can cause mold growth. Try to keep the humidity level in your home between 30 and 50 percent. Clean high humidity areas such as basements, bathrooms and kitchens frequently, and consider using a dehumidifier in particularly humid places (such as a basement).
If dust in the house causes your allergic conjunctivitis, try not to expose yourself to dust mites, especially in your bedroom. Use special blankets to reduce allergens in your bed – especially pillows – to keep dust mites away from your skin. Wash your bedding frequently, using warm heated up to at least 130ºF. When cleaning the floors, instead of using a dust cloth or a broom, use a mop or a damp cloth to catch the allergens.
If pets are a source of allergies for you, try to keep them out of the house as much as possible. It is especially important not to allow a pet in your bedroom, so that you can sleep in an allergen-free room. Consider installing wood or tile floors instead of carpet, which catches the dandruff left behind by your pets. Always wash your hands after touching a pet, and wash clothing that has been exposed to animals. Finally, always avoid rubbing your eyes; this only helps them to become more irritated.
Treatment of eye allergies with eye drops and medicine
Artificial tears
Artificial tears can help alleviate eye allergies temporarily, helping to clear allergens from the eye. In addition, they relieve dryness and irritation in the eyes, providing moisture to them. Artificial tears are available without a prescription and can be used as often as needed.
Decongestants (with or without antihistamines)
Decongestants reduce the redness of the eyes caused by allergies. They are sold as eye drops, and are available without a prescription. They can be sold simply as decongestants, or as decongestants with antihistamines, which relieve eye itching. This type of eye drops should not be used for more than two or three days, as long-term use increases the symptoms of irritation.
Oral antihistamines
Oral antihistamines may be helpful in relieving itchy eyes. However, they can cause dryness in already dry eyes and even worsen the symptoms of an eye allergy.
Antihistamines / Mast Cell Stabilizers
They are eye drops with an antihistamine to relieve itching and stabilize mastocytes (mast cells), helping to prevent eye allergies. They are used twice a day to relieve itchiness, redness, tearing and burning.
Corticosteroids
They are steroid drops that can help treat chronic and severe allergic eye symptoms such as itching, redness and swelling.