Inflammation of the conjunctiva, the membrane on the inner part of the eyelids and the membrane covering the white of the eye. The conjunctival membranes react to a wide range of bacteria, viruses, allergy-provoking agents, irritants and toxic agents. Viral and bacterial forms of conjunctivitis are common in childhood. Conjunctivitis is also called pinkeye and red eye.

The leading cause of a red eye is virus infection. Viral pink eye is usually associated with more of a watery discharge, not green or yellow in color, and is frequently associated with viral cold-like symptoms. The eyelids may be swollen. Sometimes looking at bright lights is painful. While viral pink eye, may not require an antibiotic, the doctor should see the child, as occasionally this form of pink eye can be associated with infection of the cornea, (the clear portion of the front of the eyeball). This infection must be correctly detected and treated. Viral pink eye is highly contagious.

The bacteria that most commonly cause pink eye are staphylococcus, pneumococcus, and streptococcus. Symptoms include eye pain, swelling, redness, and a moderate to large amount of discharge, usually yellow or greenish in color. The discharge commonly accumulates after sleep. The eyelids may be stuck together requiring a warm wash cloth applied to the eyes to remove the discharge. This bacterial pink eye responds to repeated warm wash cloths applied to the eyes and antibiotic eye drops or ointment.