Is it or isn’t it? Allergic conjunctivitis in a COVID-19 world

Google searches for COVID-19 symptoms spiked mid-March as many Americans came to terms with the emerging pandemic, but so did searches for another malady with the potential for overlying symptoms: allergies.

In fact, Google Trends shows U.S. queries for "is it allergies or coronavirus" peaked March 15-21 in what only weeks later would become ground zero in the fight against the novel coronavirus—New York, New Jersey, California and Florida. Other states, such as North Carolina, Georgia, Virginia and Texas, would also register high interest in a week that also, coincidentally, marked the official start of spring and, unofficially, the start of allergy season. Now, data researchers are mining Google searches once again to track the coronavirus' community spread, as well as identify other impacts or new COVID-19 symptoms.

The latest data to pique researchers' interest? Searches for "my eyes hurt" seem to be trending upward in those same hard-hit states.

These trends were noticed "almost exclusively" in areas reporting high COVID-19 cases, notes a former Google data scientist writing in The New York Times. Troubling, in the author's opinion, is that testing for "alternative explanations" doesn't seem to fit the data.

"The searches do not seem to be driven by allergies; they are not related to pollen concentrations," writes Seth Stephens-Davidowitz, continuing that searches likewise don't seem to reflect increases in screen time from devices.

"Nonetheless, doctors and public health officials should probably look closely at the relationship between COVID-19 and eye pain. If nothing else, we need to understand why there is frequently a large uptick in people telling Google that their eyes hurt when known cases of COVID-19 in a location rise to extremely high levels."

So, what is known about the ocular characteristics of COVID-19?

COVID-19 and the eyes

The AOA Health Policy Institute (HPI) notes in its statement, "Doctors of Optometry and COVID-19," that though viral conjunctival infection is usually caused by adenovirus, COVID-19 may cause ocular signs and symptoms, including photophobia, irritation, conjunctival injection and watery discharge. These are predominately self-limited but may require supportive care, the statement adds.

Additionally, a JAMA Ophthalmology report from Hubei Province, China—once epicenter of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic—provides a snapshot of the ocular manifestations in patients with COVID-19. Although small-scale, the study reported one-third of patients had ocular manifestations consistent with conjunctivitis, including conjunctival hyperemia, chemosis, epiphora or increased secretions. The study also suggested a low prevalence of SARS-CoV-2 in these patients' tears.

While there is conflicting literature as to the virus' expression in tears, the AOA advises doctors of optometry that in addition to respiratory transmission, SARS-CoV-2 may be found in the tears and conjunctiva of COVID-19 positive patients.

"Due to the close proximity of eye examinations, any interaction with patients must include the use of masks, gloves and eye protection," the AOA's guidance reads. "Goggles or eye shields MUST be worn to help prevent transmission."

On March 17, the Centers for Disease Control and Prevention (CDC) advised that providers should prioritize only urgent and emergent visits and procedures, while all "routine" eye care visits should be postponed until advised otherwise. The AOA supports the CDC guidance and notes that access to essential health care, including urgent and emergent care provided by doctors of optometry, can help reduce current and expected burdens on emergency departments.

Based on the immediate health needs of a patient, doctors of optometry can and should use their professional judgement to determine the timing and course of care, including assessing patient-expressed urgency, necessary preventive care and the monitoring and refilling of prescriptions.

Although the Times piece suggests eye pain searches may be unrelated to seasonal allergies, Hay fever symptoms, including conjunctivitis, do share many of the same signs as COVID-19 or influenza—enough similarities that media reports nationwide delineate the conditions. As pollinators ramp up in the warmer weather, so too will the usual allergic conjunctivitis cases and, conceivably, worries over COVID-19 infection.

Allergies or COVID-19?

Dry cough, congestion, drainage and limited sense of smell are all overlapping, common symptoms of seasonal allergies and COVID-19, yet less-common symptoms shared between the two include fatigue, body aches and pains, and shortness of breath (especially if asthmatic). Conjunctivitis may also fall into this category, but neither the CDC nor World Health Organization currently list it as a major symptom of COVID-19. That said, a British Journal of Ophthalmology report recently detailed the ocular complications of SARS-CoV-2, including viral conjunctivitis.

"Allergy patients frequently experience an overlap of signs and symptoms," says Renee Reeder, O.D., department chair of clinical affairs at the University of Pikeville Kentucky College of Optometry. "Patients presenting with ocular allergy will often complain of [sneezing], itchy eyes, nose and throat. Some will experience Hay fever with a low-grade fever usually under 100.0 degrees. Patients may have a bluish hue to the lids, evidence of mild angioedema and often referred to as an 'allergic shiner.'"

But that's in contrast to COVID-19 patients: fevers of 100.4 or higher, dry cough, difficulty breathing, fatigue, muscle aches and chills, loss of smell or taste, and gastrointestinal issues, Dr. Reeder notes. While itchy eyes may be associated with conjunctivitis, foreign body sensation is more common with viral forms of conjunctivitis, she says.

Doctors of optometry with additional training in ear, nose and throat evaluation may also look for a few additional signs. Whereas patients suffering from allergies will often have boggy, bluish nasal mucosa and fluid visible behind their ear drum—post-nasal drainage is a hallmark of allergy—viral patients will often have greater injection of the nasal mucosa and increased lymphadenopathy, Dr. Reeder says.

Nonetheless, doctors of optometry should take extra precautions in situations that present the potential for COVID-19 spread.

"Anecdotal evidence does suggest that a small number of patients who have COVID-19 conjunctivitis will have low levels of the virus in their tears; the virus has not been isolated from COVID patients without conjunctivitis," Dr. Reeder points out. "Additional articles suggest that conjunctivitis is more likely in those patients with more advanced disease."

This article has been reviewed by the AOA COVID-19 Evidence-based Optometry Response subcommittee.

Stay informed with the AOA's COVID-19 guidance and resources

The AOA continues to closely monitor all developments in the U.S. public health response to COVID-19, as well as institute an all-out mobilization on behalf of the profession that includes not only 24/7 advocacy for optometry, but also launching an  unprecedented, multifaceted relief and recovery package.

Given the evolving nature of this pandemic, the AOA remains committed to providing the most up-to-date information, relevant care guidance and resources, and timely reports on federal actions through  AOA's COVID-19 Crisis Response page. This online resource includes:    

• New recommendations for the reactivation of optometry services in the form of  AOA's Optometry Practice Reactivation Preparedness Guide.
• The AOA Health Policy Institute's  "Doctors of Optometry and COVID-19" statement and  FAQ.
• #AskAOA COVID-19 webinar series.
• State-by-state COVID-19 resources and information.
• Latest information from  CDC and  White House Coronavirus Task Force.