Conjunctivitis, commonly known as pink eye, is an inflammation of the conjunctiva, the thin membrane covering the white part of the eye and the inner eyelids. It can be caused by infections, allergies, or irritants. Symptoms often include redness, itching, and discharge from the eye, which can be uncomfortable but is usually not serious. There are three main types of conjunctivitis: viral, bacterial, and allergic. Viral conjunctivitis is often associated with colds, while bacterial conjunctivitis can be treated with antibiotics. Allergic conjunctivitis is triggered by allergens like pollen or pet dander and can be managed with antihistamines.