II. Causes:
We do not know why types of cysts appear, nor do we know why some persons get many of them. Often we are born with cysts under the skin.
People who smoke are more prone to the development of large types of cysts. Cysts are also more likely to become infected in smokers.
Sometimes, people who have multiple cysts have a family history of this problem.
As a person gets older, sometimes a cyst which was present since birth suddenly gets larger. When this happens, bacteria often get into the cyst and an infection occurs which can resemble a boil.