Both dry eye and allergies can significantly impact a person’s ability to work and enjoy quality of life. Differentiating between the symptoms of dry eye and those of allergy triggered discomfort is important, yet often difficult. This makes deciding on the appropriate treatment challenging.
I regularly encounter patients who have been treated for either allergies or dry eye with little to no improvement in their symptoms. After all, red, watery eyes are the stamp of both dry eyes and allergies, right? Frequently the cause is misdiagnosed, with affected patients only able to experience new found relief once the correct diagnosis is targeted. It is prudent to mention that these two conditions frequently co-exist.
Examination with key identifying questions will help to steer you down a path of dry eye vs. allergies, or a combination of the two. These basic questions include the seemingly obvious but often neglected:
- Ocular itching or hay fever,
- Sinus and lid involvement, and
- Eyedrops/preservative use and predisposing factors such as CL wear.
Schirmer testing, interferometry and meibography also strongly guide a proposed diagnosis and treatment plan
Seasonality also plays a huge role in both allergies and dry eye. Individuals who suffer from dry eye disease may experience discomfort all year round, with most finding relief in more humid climates and suffering more in drier winter climates. On the other hand, seasonal allergy sufferer’s symptoms may peak at certain times of the year when pollens are at their highest or when an individual is exposed to certain common allergens (perennial). These common allergens include pollens, pet hair, dust, certain contact lens materials and solutions.
CLINICAL DIFFERENTIATION
So clinically, how do we differentiate the two? Using vital dyes can often assist in separating dry eye from an allergy response. With dry eye we commonly see both corneal and conjunctival staining. This is less common if we are dealing solely with allergies. However, we have to remember that clinical overlap exists. For example, an individual who has ocular papillae in response to an allergen will likely show signs of surface friction and lissamine green staining just as a dry eye patient would. This reinforces why everting the eyelids and identifying papillae is a quick and effective way to identify allergies in many patients.
Conjunctival chemosis is also a tell-tale sign seen commonly with ocular allergies and not dry eye. Using tear breakup time or meniscus height/width can also help clarify the nature of the patient’s problem. In dry eye sufferers, we frequently observe a rapid tear breakup time (TBUT). Allergy sufferers on the other hand, often experience excess tearing, thus a rapid TBUT is not seen as a common thread. In some chronic allergy conditions using TBUT diagnostically may be more difficult as tearing may not be as pronounced as it is with acute sufferers.
As mentioned, contact lenses tend to be an unfortunate culprit in both allergies and dry eye. Identifying certain patterns of surface staining can suggest that a contact lens material or solution sensitivity exists. It pays to mention that Schirmer testing, interferometry and meibography also strongly guide a proposed diagnosis and treatment plan.
BASIC ALLERGY TREATMENTS
If you are still uncertain as to your diagnosis, or think a combination may exist, then there is no harm in initiating basic conservative treatment with a short term follow up plan. We call this the step wise approach. Basic allergy treatments can include:
- Introducing a topical antihistamine or mast cell stabiliser such as Patanol or non-preserved Zaditen
- Cool compress
- Non-preserved artificial tears
- If possible, avoiding any suspected allergens. This is easier said than done when the family pet is your culprit or you are uncertain of/as to the causative factor.
We also need to be aware that treatment for one condition can exacerbate the other. A key example of this is the use of antihistamines and their counterproductive effect on dry eye. Educating patients on their use of antihistamine and its flow on effects to dry eye will often send them looking for an alternative option if it means providing further relief.
An additional note, and something we all encounter far too often, is the decongestant/whitening drop “addict”. These patients tend to come out of hiding and into our chairs during allergy season. The near immediate relief followed by the dire rebound effect is why I am vocal in advising patients to throw them away and never look back. These patients commonly spend an impressive amount of time weaning off these drops due to the addictive cosmetic improvement. Often this weaning process is associated with vast degrees of discomfort and requires parallel treatment to reduce their symptoms.
NSAIDS AND STEROIDS
Sometimes allergies are easy to identify and more severe in appearance. These patients typically require more treatment to suppress the immune response. Treatments such as nonsteroidal anti-inflammatory drugs (NSAIDS) and corticosteroids are options that prove successful but carry other risks. NSAIDs are a great option if steroids are contraindicated. However, they are not as effective as steroids because they do not directly decrease histamine release from mast cells.1 They still effectively reduce pain connected with inflammation and, when used synergistically with an antihistamine/mast cell stabiliser, can serve as an effective therapy. When used four times a day, Acular (ketourlac) has shown its effectiveness for allergic conjunctivitis.2
Beginning with basics and working towards more advanced treatments is always the targeted approach. This is also true for the type of steroid used. In a study of patients with seasonal allergic conjunctivitis, fluorometholone was found to be highly effective in reducing itching, tearing and conjunctival hyperemia over time, and did not exhibit any statistically significant changes in IOP3. When considering using more penetrating steroids, you need to weigh up the pros and cons of initiating treatment. We are all too aware of the long-term risks of steroid use in chronic allergy sufferers.
Prednefrin Forte is another upper ladder option, which combines a lower dose of corticosteroid in combination with a decongestant (phenylephrine). The phenylephrine shrinks blood vessels and subsequently, in combination with the steroid, can provide rapid relief from the symptoms of allergic conjunctivitis/seasonal allergies. More severe and clinically obvious allergy sufferers such as Vernal keratoconjunctivitis may even benefit from immunosuppressants including Macrolides or Cyclosporine A. Macrolides, such as Tacrolimus, have been shown to be an excellent alternative to antiallergic and steroids for the treatment of even simple allergic conjunctivitis. A highlight of tacrolimus includes its ability to reduce allergic recurrences.4
TAKE A CAUTIOUS APPROACH
It goes without saying that when there is a combination of dry eye and allergy, then treating the underlying cause of dry eye is pivotal. A damaged ocular surface will most certainly exacerbate the symptoms of ocular allergies and vice versa.
Taking a cautious approach in identifying the correct diagnosis and initiating basic treatments before moving ahead with more advanced options is the best way to ensure the patient is being treated appropriately.
Emma Furniss is the principal optometrist at the Dry Eye Institute in Sydney (Boptom Hons, TPA, UOA) and also practices at PersonalEYES, vision specialist clinic. Her background in nutrition and pharmacy fuel a multi-disciplinary approach to eye health.
References
- Pflugfelder S, O’Brien TP, Donnenfeld ED, Karpecki PM, et al. Prevention and management of ocular inflammation across the ophthalmic spectrum: proceedings from expert roundtable discussion. Georgetown, Conn: MedEdicus. Nov 1, 2012.
- Raizman MB. Results of a survey of patients with ocular allergy treated with topical ketorolac tromethamine. Clin Ther. 1995 Sep-Oct;17(5):882-90
- Leonardi A, Papa V, Milazzo G, Secchi AG. Efficacy and safety of desonide phosphate for the treatment of allergic conjunctivitis. Cornea. 2002 Jul;21(5):476-81.
- J Nat Sci Biol Med. 2015 Aug; 6,S10–S12. Efficacy of topical application of 0.03% tacrolimus eye ointment in the management of allergic conjunctivitis Ajit Kumar Hazarika and Prodip Kumar Singh
