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Dry eye specialists should be on the lookout for ‘zebras’ in the summer
Most patients will present with common disorders, but be prepared for the occasional rare condition.
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It is summertime in the northern latitudes, and all is well in the dry eye clinics of North America. Remember how hard it was to be a dry eye doc last winter during the polar vortex? All of your patients felt lousy, and every day you questioned the wisdom of treating dry eye. Now, the weather is warm, the humidity is high, you are between the allergy vortex of the shoulder seasons, and all of your patients are convinced that you are a genius. Be careful, though. The summer clime is the perfect environment for zebras.
Common things are common. You certainly remember that old saw, “When you hear hoofbeats, think horses, not zebras.” The daily life of a dry eye expert is as filled with horses as a wrangler on the Montana plain. Except in the summer, that is. When the weather is warm and your patients are well and happy, now is the time to be on the lookout for the unusual and rare. Let me share a couple of conditions that are uncommon and easy to miss unless you have your “zebra sensor” on: molluscum contagiosum (MC) and superior limbic keratoconjunctivitis (SLK).
Lifting the upper lid
Bob Cykiert, my NYU cornea professor, once said that the only difference between a general ophthalmologist and a cornea specialist in the clinic is that the cornea specialist always lifts up the upper lid to look at the superior cornea and sclera. I am pretty sure that my fancy cornea colleagues, including Neda Shamie and Mark Milner, would take issue with that, but this little nugget of wisdom — that the only thing that separates a general ophthalmologist from a cornea specialist is looking at the superior limbus, sclera and conjunctiva, tarsal conjunctiva, and maybe even the closed upper lid — is one way to avoid missing the kind of zebra diagnosis that masquerades as the common dry eye syndrome horse. Your typical patient arrives with complaints of dryness, redness, a foreign body sensation and tearing, just like so many before. Maybe the tear osmolarity is elevated, and perhaps there is a positive InflammaDry (RPS) result. Dry eye, right? Careful! Remember, it is summertime.
On first blush, your examination seems to be pretty typical. The lid margins are unremarkable. There might be a little bit of bulbar conjunctival erythema or a tiny bit of edema. The cornea is not too exciting, either, with perhaps a small amount of punctate staining, if there is anything at all. You are about to chalk this up to mild dry eye syndrome when you remember Dr. Cykiert’s pearl and lift the upper lid while the patient looks down. Bingo! There is a wedge of inflamed conjunctiva that is almost purplish in color. When you evert the upper lid, the tarsal conjunctiva has a smooth papillary reaction, often described as “velvety.” You have just made the diagnosis of SLK. Once upon a time, you had to raid the NICU for silver nitrate capsules in order to treat this. More recently, we have been having considerable success using off-label Lotemax Gel (loteprednol etabonate ophthalmic gel 0.5%, Bausch + Lomb) to suppress inflammation and relieve symptoms. If you encounter a rare pressure rise from this treatment, you could also consider off-label Restasis (cyclosporine ophthalmic emulsion 0.05%, Allergan) dosed three or four times per day.
Looking at the lid skin
Looking at the skin of the upper lid is another effective “zebra trap,” one that can make you look like a genius if you do it routinely on first visits. That same patient comes in with the same complaints and the same first-pass exam findings, only this time you look at the conjunctiva under the lower lid and notice that there are follicles present. There is no history of upper respiratory disease or exposure to someone with pink eye, and maybe you even have a negative AdenoPlus (Nicox) test result because your technician was really on the ball and already performed the test. Asking the patient to gently close her eyes reveals a few tiny round lesions with a depressed center. Kismet! You have just diagnosed MC with secondary follicular conjunctivitis. The tiny warts of MC are caused by an infectious virus. Like everything else on earth, these viruses are subject to the laws of gravity, and when they are shed, they often end up in the eye. The conjunctivitis and symptoms associated with MC are effectively treated with topical steroids, but the ultimate treatment is to remove the MC warts and, with them, the offending virus. Surgical excision or ablation with either cryo or laser is usually necessary, especially in cases in which the symptoms return after the steroid drops are discontinued. Because the virus is extremely contagious, you should also instruct your patient to avoid “butterfly kisses” until you have treated the molluscum bodies.
At the end of the day, all four seasons bring more of what we see every day. Common things are common, even in the summer. As we dry eye syndrome/ocular surface disease doctors continually fine-tune our diagnostic protocols, we should be ever mindful of tiny tweaks that might help us to catch that occasional rarity such as SLK or MC, especially if all it takes is the extra couple of seconds necessary to look at the upper lid skin and the superior conjunctiva. Unless you are practicing in Kenya, you are still more likely to see thousands of horses for every zebra you might encounter. With ever more wonderful and exotic tests at our disposal, it is still the simplicity and elegance of an examination done well that serves us and our patients best.
Here’s hoping your summer has been filled with wonderful adventures and that the only zebras you have seen have been with your kids or grandkids at the zoo.