Yes, boils are highly contagious.  The discharge is the main mechanism that causes boils to spread from a person to another person or from one area to another within your body.  The bacterium that is causing boils to appear is within this discharge. 

Generally, when someone else has contact with the discharge of someone’s boil, they have made contact with a bacterium known as Staphylococcus aureus that lives within the discharge.  Once it has encounters someone’s skin, an infection could appear.  When this occurs the bacteria is capable of entering into another person skin through an abrasion.  After the discharge has spread to another person’s skin, the boil has as well.  If the discharge was to spread near the primary area, this could form into a carbuncle.

This is why it is important for infected patients to keep the area contained so that the discharge does not reach other areas or people.

Here are some ways to help prevent the spreading:

It is important to take all precautions to help minimize the risk of a patient’s infection from spreading.