Bacterial Conjunctivitis or Something Else?

Distinguishing between the masqueraders on this list and bacterial conjunctivitis can be tricky, even for the seasoned optometrist. However, misdiagnosis can lead to frustration for both clinician and patient when symptoms fail to clear up with prescribed therapies. This overview offers a quick guide to help you determine which ocular condition you’re dealing with, and how best to treat it once you’ve correctly identified the cause of symptoms.

FIVE OCULAR CONDITIONS COMMONLY MISTAKEN FOR CHRONIC CONJUNCTIVITIS

Allergic Conjunctivitis

In my clinic, allergic conjunctivitis is among the top three most common causes of long-standing “pink eye.” Patients present every day, reporting that they have seen multiple doctors and received antibiotics from each of them, all with little to no improvement of their symptoms.

Allergic conjunctivitis is a family of different conditions, including seasonal allergic conjunctivitis, vernal keratoconjunctivitis, atopic conjunctivitis, and perennial allergic conjunctivitis. Allergic conjunctivitis affects patients of any age, and in my experience practicing in Louisiana, there doesn’t seem to be a predilection for race or sex. It is estimated that up to 40% of the US population experiences ocular allergies, and symptoms seem to be more prevalent in the spring and summer and during seasonal changes.

Common signs and symptoms of allergic conjunctivitis include extreme itching, conjunctival hyperemia, papillary reaction, stringy discharge, and constant epiphora. The redness and hyperemia are typically minor in appearance and cause a diffuse redness throughout the eye. Papillae found on the palpebral conjunctiva is also a hallmark of allergic conjunctivitis that can be found in most patients. These can be as large as 1 mm and located under the superior lid, which are known as giant papillae. We often find that allergic conjunctivitis also presents with chemosis and swelling of the lid area (Figure).

I will typically use an antihistamine to treat mild to moderate cases of allergic conjunctivitis and a mild steroid for moderate to severe cases, especially those with associated edema and significant ocular surface inflammation.¹

Viral Conjunctivitis

Studies show that viruses cause up to 80% of acute conjunctivitis cases, although acute conjunctivitis is commonly misdiagnosed and treated as bacterial conjunctivitis.² I typically find that viral conjunctivitis has an acute onset unilaterally, with the second eye becoming involved within 2 weeks. Due to misdiagnosis and improper treatment, symptoms can linger for weeks, thanks to constant reinfection.

Typical viral infection in my clinic is caused by adenoviruses and presents with a watery discharge, follicular reaction of the palpebral conjunctiva, diffuse conjunctival injection, chemosis, ocular swelling, and subepithelial infiltrates. Swollen lymph nodes are also common in viral conjunctivitis and are rarely found in any other type of conjunctivitis. It should be noted that many types of viral conjunctivitis, especially adenoviral cases, are highly contagious, with a risk of transmission to other people reaching 50%.³

I typically treat patients who present with an established case of viral conjunctivitis with a mild steroid and refrigerated preservative-free artificial tears for a minimum of 2 weeks. For patients with new onset or acute viral conjunctivitis, I generally offer an off-label Betadine solution with povidone-iodine 5%. Two potential new treatments for viral conjunctivitis that have me especially intrigued are the ophthalmic suspension of povidone iodine 0.6% and the dexamethasone 0.1%, both of which are currently under investigation.⁴

Uveitis

In my opinion, uveitis should always be at the top of the differential diagnosis when a patient presents with diffuse redness, discomfort, and acute conjunctival hyperemia. Typically, the redness/injection is circumlimbal, giving a characteristic appearance behind the slit lamp. Varying amounts of cells/flare can also be present in the anterior chamber, so be sure to adequately check for this.

In addition to these findings, keratic precipitates can be seen, notably in the inferior half of the cornea. I also find that patients with lingering uveitis often report that the red eye is becoming worse. It’s typically not something that comes and goes with incorrect diagnosis and subsequent incorrect treatment, but rather continuously declines. To treat uveitis and relieve the patient of their symptoms, a topical steroid is typically necessary.

Dry Eye

Patients with dry eye often present with a diffuse red eye. Many of these patients have attempted to treat their presumed case of pink eye with various types of OTC drops, including redness relievers. As we know, this approach can make the situation worse, as the rebound hyperemia takes hold after the effect of the drops wears off.

To help combat this treatment misdirection, any patient with symptoms of eye redness or discomfort should be given a validated dry eye questionnaire, as well as a full dry eye workup. I recommend meibography, tear breakup time, vital dye staining, thorough slit-lamp examination, and meibomian gland expression, at a minimum. Tests for tear osmolarity and inflammation are also run on each patient in my clinic who presents with these symptoms. Appropriate testing and diagnostics will catch most patients with dry eye and help you develop a proper treatment plan.

Blepharitis

Blepharitis is caused by an overgrowth of the human body’s natural flora, notably bacteria from the Staphylococcus family (particularly Staphylococcus aureus). Most of my patients report persistent red eye lasting for months with little to no ocular discharge. They also complain of foreign body sensation and constant “trash” on their eyelids. Upon examination, a small papillary response is often present, along with diffuse injection; collarettes around the lashes, which demonstrate active Demodex; capped meibomian glands; and saponification of the eyelids.

This masquerader can be especially tricky to discern. I find that patients with chronic blepharitis can fluctuate quite widely in their presentation and symptoms from day to day. Oftentimes, these patients have been treated by a non-eye care practitioner with an antibiotic drop or ointment. These treatments can improve symptomatology, but typically when the treatment is discontinued, the symptoms return.

I often take a multifaceted approach when treating blepharitis. If saponification is present, I’ll prescribe a hypochlorous acid spray, such as hypochlorous acid 0.01% (HyClear, HyClear), Acuicyn Antimicrobial Eyelid & Eyelash Hygiene (EMC Pharma), or Avenova Antimicrobial Lid & Lash Solution (Avenova) twice daily. Saponification is caused by the Staphylococcus bacteria-producing lipases that break down the tear film’s lipid layer, resulting in a bubbly appearance. Hypochlorous acid products have antiseptic and antiinflammatory properties that work to kill bacteria, thus reducing the amount of lipase released.

Depending on the severity of the blepharitis, I consider adding tobramycin/dexamethasone ophthalmic suspension 0.3%/0.5% (Tobradex ST, Santen) four times daily to the affected eye, and debride the lashes in the office with BlephEx (Alcon) to remove the biofilm and proinflammatory debris in patients with Staphylococcus blepharitis.

PROCEED CALMLY AND CONFIDENTLY

The differential diagnosis for patients presenting with symptoms of conjunctivitis can sometimes feel like a maze, but hopefully the navigational tools and insights provided here will help you clear the path to treatment.