Common Eye Infections

Stye

A stye is an acute inflammation of the eyelid caused by an infected eyelash hair follicle or blockage of one of the oil glands that lubricate the eyeball.  The resulting collection of pus or abscess is usually caused by the Staphylococcus bacteria.  The lesion can occur on either the upper or lower eye lid and on either the inner or outer surface of the lid.  The medical term for a stye is hordeolum.   Styes occur more often in children than adults and occasionally become recurrent.  Symptoms include pain, swelling, redness and drainage of pus.  Styes usually occur spontaneously, but irritation, rubbing, eye makeup, contact lenses and poor hygiene may increase the risk of developing a stye.  Treatment is usually with hot compresses and the nodule generally ruptures on its own within two to four days.  A stye should not be pressed or squeezed in an attempt make it drain.  Occasionally a stye on the inner lid will require drainage by a physician.  A chalazion is another lump that can form on the eyelid, usually farther from the edge, and it is also caused by blockage of an oil producing gland in the eyelid.  It does not cause pain, is not infected and is often larger than a stye.  If a stye doesn’t drain and heal completely it can turn into a chalazion.  Chalazia often resolve within a few months without treatment, but may require medical intervention. 

Blepharitis 

Blepharitis is another condition affecting the eyelids and is characterized by inflammation at the base of the eyelashes.  It affects a larger area than the single lesion of the stye and is caused by bacterial or skin conditions that affect the eyelids, producing dandruff like scales.  The most common causes of blepharitis are overgrowth of the normal skin bacteria, blockage of oil glands in the eyelids or less often allergies.  Blepharitis can affect all age groups and is not contagious.  It tends to be a chronic condition causing irritation and itching and can be difficult to treat.  Treatment often includes lubricating oils, antidandruff shampoo, good hygiene and softening of crusts with the application of warm compresses.  Blepharitis is one of the skin conditions that may increase the likelihood of developing styes and chalazia. 

Conjunctivitis or Pink Eye 

Conjunctivitis is usually caused by a bacterial or viral infection affecting the outer layer of the eye.  It is often called pink eye because of the pink appearance of the sclera or white part of the eye.  It most commonly affects children and is extremely contagious.  Pink eye is spread by direct contact or by sharing an article used by an infected individual such as makeup or even a towel.  Good hygiene and hand washing are important measures for preventing pink eye.  In addition to redness, symptoms can include tearing, discharge, itching and irritation. Because of their similar signs and symptoms, allergies affecting the eyes can sometimes be difficult to distinguish from infectious pink eye.  Depending on the cause, pink eye usually lasts one to two weeks and runs its course with only symptomatic treatment.  However, some types of conjunctivitis require antibiotics. 

Several types of conjunctivitis deserve separate mention because they require special treatment to prevent complications.  Newborns can acquire conjunctival infections caused by either the gonococcus or chlamydia bacteria as they pass through the birth canal if the mother has an active case of one of these sexually transmitted diseases.  All newborns receive treatment with the instillation of a prophylactic agent into the eyes to prevent gonococcal ophthalmia and are screened for conjunctivitis caused by chlamydia.  Viral keratitis and conjunctivitis can be caused by both the herpes simplex virus (Type I which also causes cold sores) and the varicella-zoster virus (shingles).  It is important to have an ophthalmologist diagnose and treat these infections to prevent complications which can include diminished vision.