What causes inflammation of the conjunctiva?

Inflammation of the conjunctiva, also known as conjunctivitis or pink eye, can be caused by a variety of factors, including:

1. Bacterial infections: Bacteria such as Staphylococcus aureus, Streptococcus pneumoniae, and Haemophilus influenzae are common causes of bacterial conjunctivitis.

2. Viral infections: Viruses are the most common cause of conjunctivitis, particularly in children. Adenoviruses, which also cause the common cold, are a frequent cause of viral conjunctivitis. Other viruses that can cause conjunctivitis include herpes simplex virus, enteroviruses, and measles virus.

3. Allergic reactions: Allergic conjunctivitis occurs when the conjunctiva comes into contact with an allergen, such as pollen, dust, pet dander, or cosmetics. The body's immune system overreacts to the allergen, releasing histamine and other inflammatory mediators that cause symptoms such as itching, redness, and swelling.

4. Chemical irritants: Exposure to certain chemicals, such as chlorine in swimming pools, household cleaners, or industrial solvents, can cause chemical conjunctivitis. These chemicals can directly damage the conjunctiva, leading to inflammation and irritation.

5. Physical injuries: Trauma to the eye, such as a scratch or foreign body, can also cause conjunctivitis. The injury can disrupt the normal protective barrier of the conjunctiva, making it more susceptible to infection or inflammation.

6. Dry eye syndrome: Chronic dry eyes can lead to inflammation of the conjunctiva. When the eyes lack sufficient lubrication, the conjunctiva becomes irritated and inflamed.

7. Underlying medical conditions: Some systemic diseases, such as rheumatoid arthritis, lupus, and thyroid disorders, can also cause conjunctivitis as part of their symptoms.

It's important to consult an eye doctor (ophthalmologist) if you have persistent or severe conjunctivitis to determine the underlying cause and receive appropriate treatment.