What's The Difference Between Bacterial And Viral Conjunctivitis?

Conjunctivitis, also known as "pink eye," is an inflammation of the conjunctiva, says the Mayo Clinic. The conjunctiva is the clear, thin membrane that lines the eyelid and covers the white part of the eye. It helps to keep the eye lubricated and protected from infection, per the Cleveland Clinic.

There are several types of conjunctivitis, including bacterial and viral conjunctivitis. According to a 2022 article published in StatPearls, viral conjunctivitis is the most common cause of conjunctivitis, followed by bacterial conjunctivitis. In addition, the article explains that allergies and toxins cause other non-infectious forms of conjunctivitis. 

According to the Mayo Clinic, symptoms of conjunctivitis generally include redness and itching of the eye and a gritty sensation in the eye. However, since there are different types, the symptoms may vary.

If you suspect you have conjunctivitis, it is best to consult with a healthcare professional to determine the cause and appropriate treatment.

How bacterial and viral conjunctivitis differ

Bacterial and viral conjunctivitis are both types of eye infections, but different types of microorganisms cause pink eye. Bacterial conjunctivitis is caused by bacteria, while a virus causes viral conjunctivitis. According to the Centers for Disease Control and Prevention (CDC), various types of bacteria can cause conjunctivitis, including Streptococcus pneumoniae, Haemophilus influenzae, and Staphylococcus aureus. The most common viruses that cause conjunctivitis are adenoviruses, says the CDC. Others include the rubella virus, the rubeola virus, and herpesviruses.

Concerning symptoms, both types of conjunctivitis can cause swelling of the conjunctiva, itching, burning, and irritation. You might also have a sensation or feeling that there's something in the eye, per the CDC.

Bacterial conjunctivitis typically causes a thick, yellow, or green discharge, according to East Sussex Healthcare. Viral conjunctivitis can cause a watery discharge, says the CDC. Viral conjunctivitis may also occur along with respiratory infection symptoms from the flu or a cold, says the CDC.

How both types of conjunctivitis are treated

The main treatment for bacterial conjunctivitis is antibiotic eye drops or ointments, per the CDC. However, in some cases, the infection might go away without treatment. In these cases, symptoms often improve within two to five days but may take up to two weeks to completely resolve. It is important to take the full course of antibiotics as prescribed, even if symptoms improve before the medication is finished.

On the other hand, viral conjunctivitis cases are typically mild, and the infection usually resolves on its own within seven to 14 days, says the CDC. In severe cases, viral conjunctivitis can be treated with antiviral medication. However, antibiotics are not effective in treating viral infections.

In summary, the main differences between bacterial and viral conjunctivitis are their causes and treatments, while symptoms may overlap. Bacterial conjunctivitis is caused by bacteria and can be treated with antibiotics, while viral conjunctivitis is caused by a virus and typically resolves on its own. If you suspect an eye infection, it is best to consult a doctor to determine the cause and appropriate treatment.