Most patients with acute conjunctivitis are given antibiotic eye drops or ointments, but these do not speed healing and may even be harmful, according to a growing number of studies.
The most recent of these was published last month in the medical journal JAMA Ophthalmology. It involved nearly 48,000 children ages 1 to 17 with acute pinkeye from the United States. In 69 percent of cases, the children received topical antibiotic treatment.
Doctors were more likely to administer it when seeing patients in their offices (administered to 72% of patients), compared to tests in hospital emergency rooms (57%) and eye clinics (34% of patients).
But regardless of whether topical antibiotic treatment was used or not, the percentage of children who returned to the doctors for follow-up was very small, 4% of cases, meaning that withholding the drugs did not increase the risk of serious complications or prolong the eye infection.
“Nearly one in eight children develops pink eye each year, and it accounts for 1 percent of primary care physician visits for children and adults each year. Although the American Academy of Ophthalmology (AAO) has been clear for years that avoiding topical antibiotic treatment is safe and effective in most cases, many physicians still administer it to all their patients,” says Anastasios-I. Kanellopoulos, MD, an ophthalmologist, founder and scientific director of LaserVision Ophthalmology Institute, and a professor of ophthalmology at New York University.
Antibiotics may or may not work depending on the cause of the conjunctivitis. It may be a viral or bacterial infection or an allergic reaction. In all three cases, the main symptom is redness of the eyes. Depending on the cause, additional symptoms may develop, such as watery eyes, itching (pruritus), burning (stinging) sensation, sensation of a foreign body in the eye, purulent discharge or even swelling (edema) of the eyelids. Vision may also be temporarily blurred or pain may occur.
In most cases, acute conjunctivitis is caused by a virus, while in many others it is caused by an allergy, so antibiotic treatment is not necessary, according to Mr. Kanellopoulos. Overall, less than 30% of cases are caused by a bacterial infection.
A viral infection usually goes away on its own in 7 to 14 days, as do the less common cases where the cause is a bacterial infection. Allergic conjunctivitis is caused by exposure to allergens, such as pollen, insect and animal secretions (e.g., dust mites, pets), cosmetics, or even contact lenses. Allergic conjunctivitis resolves quickly when exposure to the allergen stops. Allergy drops and antihistamine pills may also improve, but not antibiotics.
Therefore, since the causes of conjunctivitis are many, a careful eye examination with a slit lamp is necessary to determine the cause. The slit lamp is the essential tool of the ophthalmologist: a powerful microscope with which to examine the eyes. All patients are tested on it (it is the device that has the position to rest the chin and the horizontal plastic strip on which the forehead rests).
“However, a previous study published in 2017 in the journal Ophthalmology showed that most patients do not turn to ophthalmologists for their conjunctivitis, but to their general practitioners. In fact, in many cases (in one in five) the antibiotic treatment administered to them is associated with that with corticosteroids (cortisone) which are contraindicated in viral conjunctivitis”, underlines the professor.
Although a course of topical antibiotic treatment may not seem serious, unnecessary treatment can lead to the development of resistant microbes. “Antimicrobial resistance can make it difficult to treat bacterial conjunctivitis if and when it develops,” she warns.
This is not the only potential risk. Antibiotic eye drops contain preservatives that can cause keratopathy, which is a problem with the cornea of the eye. Keratopathy is more common in adults, but can also be seen in children.
So when is topical antibiotic therapy absolutely necessary for acute conjunctivitis? When the situation does not improve after 2-3 weeks, Mr. Kanellopoulos answers. The same when the patient is a newborn, especially if less than a month old. It is likely that topical antibiotic therapy is also necessary in immunocompromised patients and/or with very severe symptoms.
“To treat it without topical antibiotic drops or ointments, use artificial tears, clean the eyelids with a clean, damp cloth, and apply cold or warm compresses several times a day. All of these treatments should be applied after thoroughly soaping and disinfecting your hands.
If you wear contact lenses and/or use cosmetics in the eye area, you should stop using them until you have recovered. Also replace the cosmetics you had before you developed conjunctivitis and disinfect your contact lenses. Finally, if you have viral conjunctivitis due to herpes simplex virus infection, you may need antiviral treatment,” concludes Mr. Kanellopoulos.