Pink eye, often more red than pink, is the descriptive name given to conjunctivitis- the most common eye problem seen in primary care. While infectious conjunctivitis is quite contagious, it usually is not serious and responds well to treatment. Infection of the conjunctiva, the tissue lining of the inner eyelids and front of the eyeball has several causes.

• Bacterial—if the inflamed eye has a purulent (pus) discharge, starts abruptly and is painful the infection is more likely to be bacterial. Infection usually starts in one eye and spreads to the other eye within 2 days. The most effective treatment is topical antibiotic eye drops. If symptoms become worse with treatment, an allergic reaction to the drops or the need for a different antibiotic should be considered. Often there is an associated ear infection, so an examination by the primary care clinician is important. To prevent spread, separate cloths or wet cotton balls should be used for cleansing the eye, and washcloths and towels at home should not be shared.
• Viral—also contagious, this conjunctivitis usually has a watery discharge with redness and swelling of the eyelids. It often occurs during an upper respiratory infection.

The most common causes for non-infectious conjunctivitis are allergy and trauma.

• Allergic conjunctivitis—in spring and fall many allergic individuals develop eye symptoms. Itching, eyelid swelling and a watery discharge may be associated with hay fever and asthma. Since it may be difficult to distinguish between allergy and infection, it is appropriate for the nurse to recommend an examination if there is any doubt.
• Subconjunctival hemorrhage—trauma, or even forceful coughing or vomiting can cause a red eye with a distinctive appearance. There is blood with sharply outlined edges, no pain and no visual disturbance. The adjacent white of the eye is clear and there is no discharge. No treatment is necessary and the redness resolves in a few weeks.