Actually, conjunctivitis is most commonly caused by viral infection. However, bacterial infections, allergies, other irritants and dryness also cause its occurrence. Pink eye means some bacteria and viruses can spread easily from person to person, but is not a serious health risk if diagnosed promptly. Here we classify pink eye as viral infection and bacteria infection. Viral conjunctivitis is due to adenovirus, which is the most common cause of viral conjunctivitis. The most common causes of acute bacterial conjunctivitis are staphylococcus aureus, streptococcus pneumonia, and haemophilus influenza. Although pink eye can be fine in seven days with out any medical treatment, you still need to pay attention to it in that pink eye is the basic factor to cause other eye problems. And pink eye will spread person to person, so in order to spread it to others and get worse, you'd stay at home.
