Pinkeye can be caused either by infectious or noninfectious processes. When infections are responsible, most cases are due to viral infections. Bacterial infections can also cause pinkeye symptoms, however. Pinkeye is characterized by reddening of the conjunctiva of the eyes, discharge from the eyes, and can be accompanied by other signs of infection like sinus congestion and runny nose. The eyelids may also be swollen.
With bacterial infections, there may be pus drainage from the affected eye. Eye pain, itching, swelling, and enlarged lymph nodes in front of the ears may be present. Other symptoms of infection can accompany pinkeye, such as cough or earache.
Allergic reactions are one cause of noninfectious pinkeye. This can lead to redness in the affected eye along with tearing and intense itching.