Antibiotics are not usually necessary for pink eye.Pink eye can be caused by a virus, an allergy, or bacteria.Pink eye is usually caused by a virus. Viral pink eye usually goes away on its own in a week or so. Antibiotics do not kill viruses.Pink eye can also be an allergic reaction to something like pollen, dust mites, pets, contact lenses, or cosmetics. This kind of pink eye gets better when you avoid the things that are causing the allergy. Antibiotics don't help allergies. A third type of pink eye is caused by bacteria. This can be helped by an antibiotic. However, mild bacterial pink eye almost always goes away within ten days without medication.Antibiotics can cause itching, stinging, burning, swelling and redness. They can cause more discharge. And they can cause allergic reactions in some people.