Dry eye syndrome and ocular allergies are two of the more common eye conditions people deal with each day. Despite their prevalence, it is easy to confuse dry eye symptoms with eye-related allergy symptoms, making it difficult for patients to find consistent relief.
We spoke with Tasha J. Schellenberg, OD, a clinical instructor at the Dean McGee Eye Institute/University of Oklahoma Department of Ophthalmology, to provide more information on this topic. Dr. Schellenberg specializes in optometry and primary eye care.
Allergies and Dry Eyes
Dr. Schellenberg says the confusion between dry eye and ocular allergies is due to overlap in symptoms and the fact that many patients actually have both conditions.
“It is hard as a patient to be able to tell the cause of symptoms without an examination of the ocular tissues,” she says.
Why Are My Eyes So Dry?
While the symptoms may be similar, dry eye and allergies have completely different underlying causes.
In a healthy eye, tears help keep the cornea (front surface of the eye) lubricated and clear. Each tear has three layers – an outer, oily layer; a middle, watery layer; and an inner, mucus layer. With dry eye syndrome, your eyes either do not produce enough tears or the tears produced are inadequate or unstable.
This can occur for many reasons, including:
- Meibomian gland dysfunction (blockage of oil glands)
- Age and gender (tear production decreases as you age)
- Medications (antihistamines or decongestants decrease tear production)
- Environmental factors (low humidity, allergens, smoke or chemicals)
- Not blinking enough
Allergic conjunctivitis, on the other hand, occurs when a person is exposed to an allergen. The exposure triggers an immune response that causes the release of a chemical, called histamine, that causes swelling and inflammation.
The following are common allergens that can cause eye allergies:
- Pet dander
In some cases, perfume, skin care products, and certain medications can also cause allergic reactions to your eyes.
Differentiating Allergy and Dry Eye Symptoms
The main difference in symptoms between dry eye and allergic conjunctivitis is intense itching. While itching may occur with dry eyes, it is usually more intense with allergic conjunctivitis. Any itching associated with a runny nose or watery eyes also is a sign it is related to allergies.
Still, Dr. Schellenberg notes there are many symptoms that overlap between dry eye and allergic conjunctivitis.
“Allergic conjunctivitis may cause ocular redness, watery eyes, mucus discharge, swelling or puffiness around the eyelids, blurry vision, and sensitivity to light,” she says. “Itching is also present, and there may be an intense urge to rub the eyes.”
“Dry eyes have a more varied set of symptoms. The symptoms include scratchy sensation, feeling like something is in the eye, stinging, burning, ocular redness, watery eyes, sensitivity to light, mild itch, blurry vision, and stringy mucus discharge.”
Types of Eye Allergies
There are five types of ocular allergies that can produce symptoms. Seasonal allergic conjunctivitis is the type most commonly confused with dry eye syndrome.
- Seasonal allergic conjunctivitis: This is the most common type of eye allergy and occurs when allergens are more prominent during particular seasons.
- Perennial allergic conjunctivitis: This is similar to seasonal eye allergies except symptoms occur year-round.
- Giant papillary conjunctivitis (GPC): This occurs when the inside of your eyelid gets red, swollen, and irritated. GPC is usually found in people who wear contact lenses.
- Vernal keratoconjunctivitis (VKC): This occurs when hard, elevated bumps appear on the upper eyelid due to an extreme hypersensitivity to allergens. It is more common in warm climates.
- Atopic keratoconjunctivitis (AKC): While vernal keratoconjunctivitis affects the upper eyelid, atopic ketoconjucnitivs is an allergic reaction that typically affects the lower eyelid. More specifically, the conjunctiva becomes red and swollen.
Can Allergies Cause Dry Eyes?
Yes, allergies can contribute to dry eye. Dr. Schellenberg says antihistamine medications, which help treat allergies, decrease tear production. This decrease in tear production can lead to dry eye.
“Chronic allergic conjunctivitis may also cause tissue changes in the glands within the eyelids,” she says. “This tissue change can result in the production of unhealthy tear components which leads to dry eyes.”
Because they are so closely related, having dry eye can lead to eye allergies and having eye allergies can lead to dry eye. For example, pollen and other airborne particles associated with seasonal allergies can cause inflammation that triggers dry eye. On the other hand, people with existing dry eye syndrome have issues with tear production. Without an adequate tear film present to properly lubricate the eye, the eye cannot protect against allergens.
How to Treat Dry Eyes from Allergies
There are many different treatments for dry eye ranging from over-the-counter artificial tears to prescription medications to lid procedures. Dr. Schellenberg says finding the right treatment depends on the root of the problem.
The best way to differentiate dry eye syndrome from allergies is to first have an eye exam, as they can be difficult to manage without a treatment plan from an eye doctor.
“Ocular allergies are often treated with antihistamine drops. There are several over-the-counter and some stronger prescription antihistamine drops available,” she says. “Additionally, steroid drops may be needed if ocular allergies are severe.”
Since antihistamine drops can decrease tear production, your eye doctor may recommend using preservative-free artificial tears – in conjunction with allergy drops – to keep your eyes lubricating and from drying out.
Before trying medications, there are several simple things you can try to see if your symptoms improve. Avoiding allergens altogether can limit the histamine production, thus decreasing the dry, itchy feeling in your eyes.
This may sound easier said than done, but avoid going outdoors when pollen counts are higher early at dawn and dusk. Keeping windows closed during the summer can keep allergens from getting in your house. Clean your house regularly to remove dust and pet dander that collects on surfaces.
Treating Eye Allergies and Dry Eye at DMEI
If you are experiencing symptoms of dry eye syndrome or allergic conjunctivitis, contact DMEI to schedule an appointment with one of our doctors to diagnose your condition. A comprehensive eye exam will help us learn more about the cause of your eye irritation and help us develop a personalized treatment plan.
Beyond eye drops, at DMEI, we offer both LipiFlow and intense pulsed light (IPL) treatment options for people with dry eye. LipiFlow is an FDA-approved treatment for Meibomian gland dysfunction that warms and massages the inside of the eyelids to improve how oil flows from the meibomian glands. IPL uses short bursts of specific wavelengths of light applied to the skin around the eyes to penetrate and stimulate collagen restructuring, prevent meibomian gland atrophy, decrease vascular inflammation, as well as warm the Meibomian glands internally.