What is Bacterial Conjunctivitis?
Conjunctivitis, commonly referred to as “pink eye,” is the most common eye disorder seen in medical clinics. People with conjunctivitis often have red eyes, and they may or may not experience pain, itching, or discharge from the eye. It’s often caused by a viral or bacterial infection, chemical exposure, or allergies, all of which can cause the blood vessels in the eye to expand, resulting in redness.
Despite being less common, conjunctivitis caused by bacteria is more serious and can be more difficult to treat. Viral and allergy-induced pink eye occur more often, but bacterial conjunctivitis causes more health problems overall and presents a bigger challenge for doctors.
What Causes Bacterial Conjunctivitis?
Bacterial conjunctivitis, an infection of the eye, can spread in several ways. These include touch transfer from hand to eye, coming into contact with contaminated objects, and being exposed to the respiratory droplets of an infected person.
In children, the most common bacteria causing this infection are Haemophilus influenzae, Streptococcus pneumoniae, and Moraxella catarrhalis. For adults, the primary culprits include staphylococcal species, though Haemophilus influenzae and Streptococcus pneumoniae also account for some cases. Staphylococcus aureus is commonly detected in adults and the elderly, but it can also infect children.
Interestingly, there has been a rise in conjunctivitis cases due to methicillin-resistant Staphylococcus aureus (MRSA), a bacterium resistant to many antibiotics. People who wear contact lenses are more likely to contract infections from gram-negative bacteria. In patients who are critically ill and hospitalized, Pseudomonas aeruginosa often causes the infection.
Newborns could experience acute bacterial conjunctivitis through exposure to Neisseria gonorrhoeae and Chlamydia trachomatis during birth. These bacteria can also lead to severe infection in sexually active teens and adults.
Risk Factors and Frequency for Bacterial Conjunctivitis
Acute conjunctivitis, or the sudden inflammation of the eye’s outermost layer, happens to about 6 million people a year in the US. Often referred to as “red eye,” it’s the reason for one to four percent of all general doctor visits in developed countries, with bacterial conjunctivitis being the most common diagnosis. Bacterial conjunctivitis is notably more common from December to April, and it happens more frequently in children. Interestingly, research shows that bacteria are the underlying cause of this condition in approximately 54% of cases involving children.
- About 6 million cases of acute conjunctivitis occur in the U.S. annually.
- “Red eye” results in 1-4% of general doctor visits in developed countries, mostly due to bacterial conjunctivitis.
- Peak instances of bacterial conjunctivitis are reported from December to April.
- Bacterial conjunctivitis occurs more often in children.
- Bacteria are found to be the cause in about 54% of pediatric cases of acute conjunctivitis.
- However, a 2017 survey reported only 10% of conjunctivitis cases in 3000 children were caused by bacteria.
- Despite this, doctors’ presumptive treatment often involves higher rates of antibiotic use than may be needed.
Signs and Symptoms of Bacterial Conjunctivitis
Bacterial conjunctivitis is an eye condition that often manifests as red, teary eyes with pus-like discharge. Symptoms can last from less than 3 to 4 weeks (acute) to over four weeks (chronic). Associated discomforts may include pain, itchiness, vision loss, and light sensitivity. Clinicians typically take a detailed patient history, taking note of any past trauma or similar episodes, treatments received, contact lens use, immune status, sexual history, and perhaps any ear-related symptoms, as children with this condition can also have ear infections.
While symptoms can often vary significantly and overlap with other causes of conjunctivitis, there are key signs that can suggest a bacterial origin. Traditionally, pus-like or mucus-filled discharge from the eyes could indicate bacterial conjunctivitis, while watery discharge is more consistent with a viral or allergy-associated condition. However, this notion has been challenged due to the absence of clear evidence. Later studies have noted that eyes sticking together, absence of itchiness, and no past instances of conjunctivitis may be significant predictors of bacterial conjunctivitis. Additionally, crusty eyes in the morning, the presence of mucus or pus-like discharge from the eyes, no burning sensation, and lack of watery discharge may be associated with bacterial conjunctivitis.
The primary physical signs of bacterial conjunctivitis are red eyes coupled with pus-filled discharge. A thorough eye examination should also assess vision clarity and possible corneal damage. Occasionally, using devices like slit lamps can help in the examination, but these aren’t always available in primary healthcare settings. If the patient is a child and reports ear symptoms, clinicians should also investigate a possible concurrent ear infection.
Testing for Bacterial Conjunctivitis
When it comes to diagnosing and assessing bacterial conjunctivitis, laboratory and imaging tests aren’t generally that helpful. However, there are a few instances where doctors will recommend taking samples from the eye’s surface, a procedure known as conjunctival cultures. This is usually done if there’s a suspicion of a severe type of eye infection in newborns known as ophthalmia neonatorum, or if there’s a lot of pus-like discharge from the eye that could indicate a gonococcal or chlamydial infection.
Conjunctival cultures can also be useful if someone keeps getting conjunctivitis, or if previous treatments haven’t worked.
Treatment Options for Bacterial Conjunctivitis
When it comes to managing acute bacterial conjunctivitis, or “pink eye”, the decision to use antibiotics depends on several factors. These factors include the doctor’s assessment of the patient’s condition, the benefits of the treatment, the natural progression of the disease if left untreated, issues around antibiotic resistance, and the aim of using antibiotics responsibly.
It is often challenging for doctors to distinguish bacterial conjunctivitis from other eye conditions, and as such, they often choose to prescribe antibiotics as a precautionary measure. While studies have shown that only around half of pink eye cases in children are actually bacterially caused, antibiotics are prescribed in up to 80 to 95 percent of these cases. That said, treatment with topical (applied directly to the eye) antibiotics has been shown to alleviate symptoms, speed up recovery, and reduce the spread of the infection, allowing patients to return to school or work quicker.
It’s also worth noting that without treatment, bacterial conjunctivitis typically clears up within a week. Additionally, the increasing resistance of bacteria to antibiotics is a concern that doctors take into account when considering treatment options. Therefore, mild cases of bacterial conjunctivitis might be treated with topical antibiotics, or simply monitored without using antibiotics. However, in more complex cases – such as in patients with a weakened immune system, contact lens wearers, or suspected gonococcal or chlamydial infections – doctors usually prescribe antibiotic treatment. If antibiotics are chosen, they should be broad-spectrum and effective against a variety of bacteria.
Commonly prescribed eye medications include aminoglycosides, polymyxin B combination drugs, macrolides, and fluoroquinolones. Antibiotic eye treatments usually last five to seven days. However, there is growing resistance to most classes of these drugs, making some of them, like erythromycin, less effective. Newer antibiotics like fluoroquinolones are generally effective for treating bacterial conjunctivitis, but they can be expensive. These are generally used in areas with a high resistance to other antibiotics. Bacterial conjunctivitis caused by gonorrhea or chlamydia requires oral antibiotics.
In some cases, bacterial conjunctivitis appears alongside acute ear infections, and will require oral antibiotics. Newborns with conjunctivitis caused by Chlamydia require treatment with both oral and topical erythromycin for 14 days. If gonorrhea is causing the infection, it requires hospitalization, a dose of ceftriaxone either through an IV or a muscle injection, and eye washing until the infection clears up.
Follow-up appointments are recommended if symptoms of bacterial conjunctivitis do not improve after a day or two.
What else can Bacterial Conjunctivitis be?
When trying to diagnose bacterial conjunctivitis (an eye infection), there are other conditions that might seem similar. These include conjunctivitis caused by viruses or allergies. Key signs of virus or allergy-induced conjunctivitis can often be a clear liquid coming from your eyes or a feeling of itchiness.
In addition, if your eye has been injured or traumatized, it can show symptoms similar to bacterial conjunctivitis. Other conditions that could look like bacterial conjunctivitis but are actually different include keratitis, which is an infection of the cornea (the clear front surface of your eye), and iridocyclitis, which is inflammation of the iris (the colored part of your eye). These conditions need to be ruled out because if left untreated, they can result in serious harm to your eye health.
What to expect with Bacterial Conjunctivitis
The outlook for straightforward cases of bacterial conjunctivitis (pink eye) is generally positive. Complete recovery and minimal complications can be expected with both antibiotic treatment and careful watch-and-wait strategies.
Possible Complications When Diagnosed with Bacterial Conjunctivitis
While complications from bacterial conjunctivitis, commonly known as pink eye, are rare, there are serious potential issues that can arise from severe infections. These include keratitis, which is inflammation of the cornea, ulcers on the cornea, corneal rupture, and even blindness.
List of possible severe complications:
- Keratitis (inflammation of the cornea)
- Corneal ulcers
- Perforation of the cornea
- Blindness
Preventing Bacterial Conjunctivitis
It’s important for patients to learn about the warning signs and symptoms of bacterial conjunctivitis. People who wear contact lenses should know that they must remove and stop wearing their lenses until their treatment is finished and their symptoms have resolved. It’s crucial to prevent spreading the infection, with a main focus on regular hand washing.
Teens and adults with gonorrhea or chlamydia should receive advice about safe sex habits and treating their partners to prevent further spread of the infection. Educating parents and school administrators about this condition can help minimize the number of school days children miss due to it. Once treatment begins, children can generally return to their usual school activities.
