How Do I Know if I Have Bacterial or Viral Conjunctivitis?

Medically Reviewed on 1/12/2022
The symptoms of bacterial vs. viral conjunctivitis may be similar. But a doctor can easily distinguish between the two.
The symptoms of bacterial vs. viral conjunctivitis may be similar. But a doctor can easily distinguish between the two.

Conjunctivitis is more commonly known as pink eye. It is the inflammation of the conjunctiva, which is the outer layer that covers the white part of your eyeball.

There are different types of conjunctivitis based on the cause. Of these, bacterial and viral conjunctivitis are more common. The symptoms of bacterial vs. viral conjunctivitis may be similar. But a doctor can easily distinguish between the two.

Types of conjunctivitis

Conjunctivitis can be of two types — infectious and noninfectious:

Noninfectious conjunctivitis is not contagious and is caused by allergens like pollen, dust, and so on.

Infectious conjunctivitis is highly contagious. It can easily spread from person to person. It has the following types:

Viral conjunctivitis

As one of the types of infectious conjunctivitis, viral conjunctivitis is highly contagious. The virus can spread to your eyes if you touch them with contaminated hands. It can spread through tears, eye discharge, mucus droplets, or saliva.

Adenoviruses commonly cause viral conjunctivitis. But rubella virus, herpes virus, varicella-zoster virus, Epstein-Barr virus, and some picornaviruses can cause viral pink eye as well.

Bacterial conjunctivitis

Bacterial conjunctivitis is also highly contagious. It can spread if your eyes come in contact with contaminated objects like contact lenses. You can get it through hand-to-eye contact, through sexual acts involving eye-to-genital contact, or from mother to baby. The bacteria can even spread through respiratory droplets.

These bacteria can cause bacterial pink eye:

Bacterial vs. viral conjunctivitis

If you have pink eye, it can be viral or bacterial. These differences between bacterial and viral conjunctivitis can help you find out what you have.

Symptoms of viral conjunctivitis

The main symptom of viral conjunctivitis is pink eye. But a person with viral conjunctivitis also has a cold, cough, sneezing, or respiratory infection, which is a telltale sign of viral infection.

Depending on the virus, some other symptoms may also be seen. These symptoms can help doctors diagnose the underlying infection causing viral conjunctivitis. Adenoviruses can cause symptoms such as fever and sore throat. Some adenoviruses and the herpes virus can cause keratoconjunctivitis or the inflammation of the conjunctiva and cornea of your eye. Rubella or measles virus can cause rash, fever, and cough.

Symptoms of bacterial conjunctivitis

Signs and symptoms of bacterial conjunctivitis overlap with other causes of conjunctivitis, including viral and allergic conjunctivitis, which can make diagnosis difficult. Typical signs and symptoms include:

  • Red or pink eye
  • Eye discharge
  • Crusty eyes due to discharge, making it difficult to open them
  • Chemosis or blistering on the outer surface of the eye
  • Decreased vision
  • Swelling and pain in eyelids


Your doctor can tell whether your conjunctivitis is caused by a virus, bacteria, or allergen. They will check your medical history and symptoms and examine your eye.

Bacterial and viral pink eye have similar signs. Both involve redness or swelling in your eye. But other symptoms of infection can help your doctor find out the exact cause of conjunctivitis. Your doctor will check for these specific symptoms, which can even help you tell bacterial vs. viral conjunctivitis apart:

  1. If you have viral conjunctivitis, you may develop a cold, cough, sneezing, respiratory infection, or other cold-related symptoms. These symptoms aren’t seen in people with bacterial conjunctivitis.
  2. If you have bacterial conjunctivitis, you may have a thick white, yellow, or green gunk or discharge coming out of your eye. You may also have a crusty eye due to the discharge. In viral conjunctivitis, the discharge from your eye will be watery instead of thick.
  3. Viral conjunctivitis is often seen in both eyes at the same time. But bacterial infections rarely happen in both eyes.
  4. If you have pink eye along with an ear infection, you may have bacterial conjunctivitis.

Sometimes, you may show symptoms of conjunctivitis but may not be able to identify the cause. To rule out allergic conjunctivitis, your doctor will check if it occurs seasonally when the pollen count is high. If your eyes itch intensely and you have signs of allergy such as hay fever, asthma, or eczema, you may have allergic conjunctivitis.


Pink Eye (Conjunctivitis) Symptoms, Causes, Treatments See Slideshow


If you have conjunctivitis, you must wash your hands regularly, use separate towels, and avoid close contact with other people. Also, avoid wearing contact lenses as they may be contaminated with bacteria or viruses. It can increase your risk of getting keratitis or corneal inflammation.

Treatment of viral conjunctivitis

Viral conjunctivitis doesn’t have any specific treatment. Your doctor may prescribe antihistamines or cold compresses to reduce symptoms.

Antiviral medication may be used for severe cases of herpes or varicella-zoster virus infection.

Treatment of bacterial conjunctivitis

Bacterial conjunctivitis is treated with antibiotics in the form of eye drops or injections. Viral conjunctivitis often disappears on its own in some days and doesn’t require medical treatment. On the other hand, bacterial conjunctivitis requires antibiotic treatment.

If you have severe infectious conjunctivitis, your doctor may suggest an antiseptic and steroids to reduce swelling or inflammation.

Medically Reviewed on 1/12/2022
CDC: "Diagnosis," "For Clinicians."

JAMA: "Conjunctivitis."

Veterans Optometry Partners of America: "What is the Difference Between Viral and Bacterial Pink Eye?"