<P> Symptoms result from the release of histamine and other active substances by mast cells, and consist of redness (mainly due to vasodilation of the peripheral small blood vessels), swelling of the conjunctiva, itching, and increased production of tears . </P> <P> Bacterial conjunctivitis causes the rapid onset of conjunctival redness, swelling of the eyelid, and a sticky discharge . Typically, symptoms develop first in one eye, but may spread to the other eye within 2--5 days . Conjunctivitis due to common pus - producing bacteria causes marked grittiness or irritation and a stringy, opaque, greyish or yellowish discharge that may cause the lids to stick together, especially after sleep . Severe crusting of the infected eye and the surrounding skin may also occur . The gritty or scratchy feeling is sometimes localized enough that patients may insist that they have a foreign body in the eye . </P> <P> Common bacteria responsible for non-acute bacterial conjunctivitis are Staphylococcus, Streptococcus, and Haemophilus . Less commonly chlamydia may be the cause . </P> <P> Bacteria such as Chlamydia trachomatis or Moraxella can cause a non-exudative but persistent conjunctivitis without much redness . Bacterial conjunctivitis may cause the production of membranes or pseudomembranes that cover the conjunctiva . Pseudomembranes consist of a combination of inflammatory cells and exudates and adhere loosely to the conjunctiva, while true membranes are more tightly adherent and cannot be easily peeled away . Cases of bacterial conjunctivitis that involve the production of membranes or pseudomembranes are associated with Neisseria gonorrhoeae, β - hemolytic streptococci, and Corynebacterium diphtheriae. C. diphtheriae causes membrane formation in conjunctiva of non-immunized children . </P>

Staphylococcus is the only causative agent of conjunctivitis