About Allergic Conjunctivitis (Pink Eye)

Overview

Allergic conjunctivitis is an inflammatory condition of the eye that occurs when the conjunctiva, the thin membrane covering the white part of the eye and the inner surface of the eyelids, becomes hypersensitive to allergens. It is characterized by an immune response triggered by exposure to external allergens, such as pollen, dust mites, pet dander, or certain chemicals. This immune response can be triggered by immunoglobulin E (IgE) or T lymphocytes. Allergic conjunctivitis can manifest in different forms, including seasonal allergic conjunctivitis (triggered by pollen in certain seasons), perennial allergic conjunctivitis (caused by indoor allergans year-round), vernal keratoconjunctivitis (a chronic type common in children linked to seasonal allergies), atopic keratoconjunctivitis (affecting the eye covering and skin around the eyes, often in people with eczema or asthma), and giant papillary conjunctivitis (irritation caused by contact lenses or foreign objects in the eye). Common symptoms include itching, redness of the eyes, eye swelling, sensitivity to light, tearing, burning sensation, and a feeling of having something in the eye. While allergic conjunctivitis does not usually affect vision, it can significantly impact a person's quality of life. Early diagnosis and appropriate treatment are important to manage symptoms and prevent complications.

Causes and Risk Factors

Allergic conjunctivitis is caused by the body's reaction to certain substances it is allergic to, such as:

Pollen from trees, plants, grasses, and weeds
Dust mites
Animal dander
Molds
Contact lenses and lens solution
Cosmetics

Non-modifiable risk factors for allergic conjunctivitis cannot be changed or controlled. These include:

Having other signs of allergic disease, such as hay fever, asthma, and eczema
Genetic factors

Modifiable risk factors of allergic conjunctivitis can be influenced or changed. These include:

Exposure to changing climates and increasing pollution
Cigarette pollutants
Occurrence of allergy in early childhood

It's important to note that while these risk factors can contribute to the development of allergic conjunctivitis, individual susceptibility may vary. It's always a good idea to consult with a healthcare professional for personalized advice and management options.

Symptoms

The most common early symptoms of allergic conjunctivitis include:

Irritation of the eyes
Redness or bloodshot appearance of the eyes
Increased tearing or watering of the eyes

As allergic conjunctivitis progresses or becomes more severe, other common symptoms may occur, such as:

Itching sensation in the eyes (a key symptom)
Sensation of a foreign body in the eyes
Clear or mucous discharge from the eyes
Swelling of the conjunctiva (the thin membrane covering the white part of the eye)

In later stages, chronic inflammation can lead to additional symptoms, including:

Photophobia (sensitivity to light)
Eye pain
Visual impairment: A problem with vision that makes it hard to see clearly, even with glasses or contact lenses

It's important to note that allergic conjunctivitis usually affects both eyes at the same time, unlike bacterial or viral conjunctivitis which may start in one eye and spread to the other. If you experience these symptoms, it is advisable to consult with a healthcare professional for an accurate diagnosis and appropriate treatment.

Diagnosis

To diagnose allergic conjunctivitis, the following examinations, tests, and procedures are commonly performed:

Medical and physical examination: Before doing a physical exam, the healthcare professional will take a medical history to understand any symptoms and past eye issues. The physical exam involves a close look at the eyes and surrounding areas, including the eyelids, eyelashes, tear film, conjunctiva (the thin layer over the white part of the eye and under the eyelids). This cornea is also examined. A detailed assessment using a slit-lamp biomicroscopy is recommended for a more thorough evaluation.
Allergy assessment: An allergy evaluation is important in diagnosing allergic conjunctivitis. Aeroallergen skin prick testing on the forearm is commonly used to identify specific allergens. If skin testing is not advised or if results are unclear, blood tests measuring specific IgE (immune system proteins) may be used instead.
Laboratory tests: Lab tests can support the diagnosis of allergic conjunctivitis. These may include skin tests for specific allergens using scratch tests or intradermal injections (shots given just under the surface of the skin). Skin prick tests are also suggested for allergen immunotherapy. A sample of cells from the inner eyelid, called a conjunctival scraping, may be taken to check for the presence of certain immune cells called eosinophils, which can indicate an allergic reaction.

To determine the severity of allergic conjunctivitis, additional examinations may include:

Slit-lamp biomicroscopy: This detailed examination helps assess the cornea and limbus, which is the border area between the cornea and the white part of the eye, at high magnification, especially in moderate to severe cases.
Fluorescein ocular surface staining: This test involves using a special dye under cobalt blue light to identify any damage or irregular areas on the eye’s surface.

Remember, these examinations and tests should be performed by a healthcare professional experienced in diagnosing and managing eye conditions.

Treatment Options

The goals of treatment for allergic conjunctivitis are:

Symptom relief: The primary goal is to alleviate the symptoms associated with allergic conjunctivitis, such as itching, redness, and swelling of the eyes.

The recommended treatments to achieve these goals include:

Supportive treatment: This involves identifying and avoiding allergens that trigger the allergic reaction. Non-medication therapies like cold compresses and avoiding rubbing the eye can provide symptomatic relief.
Artificial tears: Saline based lubricating eye drops can help wash away allergens and reduce irritation on the surface of the eye, providing relief.
Topical anti-histamines: Selective H1 antagonists, such as levocabastine and emedastine, are commonly used as eye drops to quickly relieve symptoms by blocking histamine receptors. Histamine is a natural substance in the body that causes allergy symptoms like itching and swelling.

It is important to note that these recommendations are general and may vary based on individual circumstances. Consult with a healthcare professional for personalized advice.

Medication dosing may be affected by many factors. Check with your health care professional about dosing for your individual situation. Side effects can occur. Check with your health care professional or read the information provided with your medication for side effect information.