Doctor's Notes on Eye Allergies
Allergic reactions to environmental agents that involve the eyes are common. An allergic reaction that affects the conjunctiva, a clear layer of mucous membrane overlying the eyes, is referred to as allergic conjunctivitis, which is divided into several subtypes, with the most common being seasonal allergic conjunctivitis (SAC) and perennial allergic conjunctivitis (PAC). SAC and PAC are triggered when someone who is allergic to a particular substance, such as pollen, is exposed to it. Common allergens include trees, grasses, weeds, dust mites, pets (especially cats and dogs), and molds.
Symptoms of allergic reactions that affect the eyes include itchy eyes, watery eyes, red eyes, swollen eyes, burning sensation, and mattering and/or mucous production. Symptoms of pain, blurred vision, double vision, or changes in vision are not typical eye allergy symptoms and require medical attention.
Eye Allergies Symptoms
Itching is the most common symptom of any allergic reaction, and this is also true for allergic conjunctivitis. In addition to ocular itching, the following eye allergy symptoms and signs are also commonly reported:
- Burning sensation
- Mattering and/or mucous production
- Mild swelling around the eyes
- Importantly, symptoms of pain, blurred vision, double vision, or changes in vision are not typical for allergic conjunctivitis and warrant prompt medical attention.
Eye Allergies Causes
Ocular (eye) allergies often affect the conjunctiva, a clear layer of mucous membrane overlying the eyes. This clear layer of mucous membrane is the same type of mucous membrane that lines the inside surface of the nose. As these two areas are so similar, the same allergens (substances that induce an allergic reaction) can trigger the same allergic response in both areas.
Common allergens include the following:
- Dust mites
- Pets (especially cats and dogs)
The main difference between SAC and PAC is the timing of the symptoms.
- In an individual with SAC, symptoms are generally limited to a defined period of time.
- Typically, tree pollen causes symptoms in the spring, grasses cause symptoms in the summer, and weeds trigger symptoms in late summer and fall time until the first hard frost.
- Symptoms generally resolve during other times of the year, particularly during the wintertime.
- In an individual with PAC, symptoms are generally present throughout the year.
- Instead of being triggered by outdoor allergens, symptoms are triggered by indoor allergens, such as dust mites, pets, mold, and even cockroaches, particularly in urban areas.
- Individuals with PAC may still experience a seasonal worsening of symptoms if they are also sensitized to outdoor allergens in addition to their indoor allergens.
Red, burning, itching, tearing eyes are the main symptoms of allergic conjunctivitis. The condition affects millions of Americans. More than one-third of children suffer from allergies. About 30% to 50% of children who have one parent with allergies will develop allergies. About 60% to 80% of children who have two allergic parents will develop allergies. Sufferers can feel downright miserable. Allergies cause fatigue, difficulties performing everyday activities, and may interfere with sleep. The condition may occur year round or seasonally. People who suffer may have dark circles under the eyes, known as allergic shiners. There are different types of allergic conjunctivitis and different triggers. Effective treatment depends on the type the patient has as well as identifying their unique triggers.
Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.