Commonly known as pinkeye, Conjunctivitis is the inflammation of the outer most layer of the eye and the inner side of the eyelid. Conjunctivitis infections commonly come in one of three flavours: viral, bacterial, or allergic. There is, however, several other cases of less common conjunctivitis: - Chemicals - Thermal and ultraviolet burns - Foreign bodies - Overuse of contact lenses - Toxins - Vitamin deficiency - Dry eye, sometimes due to inadequate eyelid closure - Exposure to chickens infected with Newcastle disease Lets take a quick look at the three most common types of conjunctivitis. The first is viral conjunctivitis. This type is transmitted by contact with a variety of contagious viruses. These required viruses need not be any harsher than the common cold virus, as these cases are generally associated with upper respiratrory tract symptoms. Bacterial conjunctivitis is most commonly caused by the infected's own skin or respiratory flora due to pyogenic bacteria. Another common way to spread infection, generally by females, is through sharing of facial lotions or eye makeup. And lastly, it is possible to share this kind of "pinkeye" through contact with other people and/or their environment. The last form that we will be looking at is allergetic conjuctivitis. This type generally follows a seasonal pattern, and is more common among those with allergic conditions. Unlike the others, allergetic conjuctivitis tends to take over both eyes, and is accompanied by swollen eyelids. It is caused by reactions to such substances as perfume, drugs, cosmetics, contact lenses, or protein deposits.