Conjunctivitis or Eye Flu: know the difference

Conjunctivitis (Pink Eye/Eye Flu)

Conjunctivitis, commonly known as pink eye, is an inflammation of the conjunctiva, which is the outermost layer of the white part of the eye and the inner surface of the eyelid. This condition causes the eye to appear pink or reddish and may result in various symptoms, including pain, burning, scratchiness, or itchiness. The affected eye may also produce increased tears or become “stuck shut” in the morning due to discharge. Swelling of the white part of the eye and itchiness, particularly in allergic cases, are also common symptoms. Conjunctivitis, which can affect one or both eyes, is a prevalent condition worldwide.


  1. Infectious Causes:
  2. Non-Infectious Causes:
    • Allergic: Allergic conjunctivitis results from an allergic reaction to substances like pollen, animal hair, dust mites, perfumes, or cosmetics. This type of conjunctivitis is characterized by redness, swelling, itching, and increased tear production. It is the most common type of conjunctivitis, affecting 15% to 40% of the population.
    • Chemical: Chemical conjunctivitis is caused by exposure to acidic or alkaline substances, leading to conjunctival burns and inflammation. Alkali burns are particularly severe and can result in significant eye damage. Immediate irrigation with saline or Ringer’s lactate solution is crucial for treatment.

Signs and Symptoms

  • General: Conjunctivitis typically presents with bloodshot eyes, redness, swelling of the conjunctiva, and watering of the eyes. The pupils should be normally reactive, and visual acuity should remain normal. Other common symptoms include:
    • Viral: Excessive watering, itching, watery discharge, and symptoms of upper respiratory infections such as a common cold or sore throat. The infection usually starts in one eye but can easily spread to the other.
    • Allergic: Redness, swelling, itching, and increased tear production due to histamine release from mast cells.
    • Bacterial: Rapid onset of redness, swelling, sticky discharge, grittiness, and severe crusting around the infected eye, particularly in the morning.


The diagnosis of conjunctivitis is often based on clinical signs and symptoms. In certain cases, a sample of the discharge may be taken for culture to determine the specific cause. Diagnostic methods include the following:

  • Clinical Examination: A thorough eye examination, often using a slit lamp, to observe the conjunctiva and other eye structures.
  • Culture Tests: Swabs for bacterial or viral cultures in persistent or severe cases.
  • Patch tests are used to identify specific allergens in allergic conjunctivitis.
  • Biopsy: Occasionally performed when granulomatous diseases or dysplasia are suspected.
Conjunctivitis or Eye Flu


Treatment for conjunctivitis varies depending on the underlying cause.

  • Viral Conjunctivitis: Most cases of viral conjunctivitis resolve on their own without specific treatment. Antihistamines or mast cell stabilizers may be used to alleviate symptoms. In cases of herpetic keratoconjunctivitis, antiviral medications like acyclovir are necessary.
  • Bacterial Conjunctivitis: While bacterial conjunctivitis often resolves without treatment, antibiotics can shorten the duration of the illness. Antibiotics are recommended for contact lens wearers, immunocompromised individuals, and those with severe symptoms or infections caused by gonorrhea or chlamydia.
  • Allergic Conjunctivitis: Mild cases can be managed with cool water rinses and artificial tears. More severe cases may require nonsteroidal anti-inflammatory medications, antihistamines, or topical steroid drops.
  • Chemical Conjunctivitis: Immediate irrigation with saline or Ringer’s lactate solution is essential. Chemical burns, particularly alkali burns, require urgent medical attention to prevent severe eye damage.


Preventative measures for conjunctivitis include:

  • Hygiene: proper handwashing and avoiding touching the eyes with unwashed hands.
  • Vaccination: Vaccination against pathogens such as Haemophilus influenzae, pneumococcus, and Neisseria meningitidis can help prevent certain types of conjunctivitis.
  • Avoiding Allergens: Minimizing exposure to known allergens like pollen, dust mites, and animal dander.


It is the most common eye disease, affecting millions of people annually. In the United States, acute conjunctivitis affects an estimated 3 to 6 million people each year. The condition imposes significant economic and social burdens, with costs related to treatment and loss of productivity. Seasonal trends have been observed, with bacterial conjunctivitis peaking from December to April, viral conjunctivitis in the summer months, and allergic conjunctivitis in the spring and summer.

Historical Outbreaks

Conjunctivitis can lead to significant outbreaks, as seen in September 2023 in Pakistan. The outbreak, which started in Karachi, quickly spread to Lahore, Rawalpindi, and Islamabad, resulting in over 86,133 reported cases in Punjab alone. The rapid spread of the disease led to the temporary closure of schools and highlighted the importance of effective public health measures in controlling infectious diseases.

Society and Culture

It imposes economic and social burdens. In the United States, the cost of treating bacterial conjunctivitis is estimated to be between $377 million and $857 million per year. Approximately 1% of all primary care office visits are related to conjunctivitis, with 70% of acute conjunctivitis cases presenting to primary care and urgent care facilities.


Conjunctivitis, or pink eye, is a common and often self-limiting condition that can be caused by viral, bacterial, allergic, or chemical factors. Proper diagnosis and treatment are essential for managing the condition and preventing its spread. Good hygiene practices, such as handwashing and avoiding contact with infected individuals, can help prevent conjunctivitis. Vaccination against specific pathogens also plays a crucial role in prevention. While most cases resolve without complications, severe or persistent symptoms may require further medical evaluation and treatment.

For more medical insights and educational content, visit my website at

Also Read:

  1. Unveiling the Truth: Debunking Common Myths About Lymphoma
  2. Recognizing the Signs and Symptoms of Chronic Kidney Disease
  3. Hematuria: Understanding, Types, Causes
  4. Alport Syndrome
  5. Salt & Human Health: A Detailed Guide

Frequently Asked Questions

Reference List


All Tags

Related Posts

Follow Me

Tanzir Islam Britto

Hello, I'm Dr. Tanzir Islam Britto. As a dedicated physician, I've embarked on my medical journey at Bangabandhu Sheikh Mujib Medical College (BSMMC), previously known as Faridpur Medical College, where I pursued my Bachelor of Medicine and Bachelor of Surgery (MBBS). I completed my degree at Shahabuddin Medical College (SMC). Alongside my medical career, I am an amateur writer and an active social media advocate, where I share insights into health, wellness, and more.

Other Posts:

Conjunctivitis (Pink Eye/Eye Flu) Conjunctivitis, commonly known as pink eye, is an inflammation of the conjunctiva, which is the outermost...

Social media can be a good thing. It can help you to connect with people, find like-minded communities, view content...

Researchers have unveiled groundbreaking insights into “super-agers,” elderly individuals whose cognitive abilities match those of much younger people. This research,...

Scroll to Top