Conjunctivitis, commonly known as pink eye, is an inflammation of the conjunctiva, the clear membrane that covers the white part of the eye and lines the inner surface of the eyelids. This condition can be caused by various factors, including infections, allergies, or irritants. Understanding the symptoms, causes, and types of conjunctivitis is essential for proper diagnosis and management.

Symptoms:

1. Redness: The whites of the eyes appear pink or red.
2. Itching: Persistent itching or discomfort in the eyes.
3. Tearing: Excessive tearing or watery eyes.
4. Swelling: Swelling of the conjunctiva or eyelids may occur.
5. Discharge: Depending on the cause, there may be a discharge from the eyes, which can be watery, thick, or contain pus.
6. Sensitivity to Light: Some individuals may experience increased sensitivity to light.
7. Foreign Body Sensation: A feeling of having something in the eye.

Causes:

1. Viral Infections: Viruses, such as adenoviruses, are common causes of viral conjunctivitis. It can spread through respiratory droplets or contact with contaminated surfaces.
2. Bacterial Infections: Bacterial conjunctivitis is often caused by bacteria like Staphylococcus aureus or Streptococcus pneumoniae. It can result from direct contact with an infected person or from contaminated objects.
3. Allergies: Allergic conjunctivitis is triggered by allergens like pollen, pet dander, or dust mites, leading to an immune response and inflammation.
4. Irritants: Exposure to irritants like smoke, chemicals, or contact lenses can cause irritant conjunctivitis.

Types:

1. Viral Conjunctivitis: Commonly caused by adenoviruses, viral conjunctivitis is highly contagious and often associated with upper respiratory tract infections. It can spread easily in crowded places.
2. Bacterial Conjunctivitis: Caused by bacterial infections, this type may produce a thick, yellow or greenish discharge. It is also contagious and can be transmitted through direct contact or by sharing personal items.
3. Allergic Conjunctivitis: Triggered by exposure to allergens, allergic conjunctivitis is not contagious. It can be seasonal, such as hay fever, or perennial, occurring year-round.
4. Irritant Conjunctivitis: Resulting from exposure to irritants like smoke, chemicals, or chlorine in swimming pools, irritant conjunctivitis is not contagious.