Conjunctivitis, or “pink eye”, is redness and inflammation of the membranes (conjunctiva) covering the whites of the eyes and the membranes on the inner part of the eyelids. These membranes react to a wide range of bacteria, viruses, allergy-provoking agents, irritants, and toxic agents, as well as to underlying diseases within the body. Viral and bacterial forms of conjunctivitis are common in childhood, but they occur in adults as well. Pink eye can occur in people of any age. Overall, however, there are many causes of pink eye.