Cysts can arise through a variety of processes in the body, including.  1 wear and tear or simple obstructions to the flow of fluid, 2  infections, 3  tumors, 4  chronic inflammatory conditions, 5  genetic (inherited) conditions,  defects in developing organs in the embryo.
1 Acute * sinusitis often develops after a person has had a cold, with symptoms lasting less than 3 weeks. 2  Chronic * sinusitis can last 3 to 8 weeks or longer; it often occurs in people who have allergies or asthma. 3  Recurrent sinusitis consists of several acute episodes of sinusitis in 1 year.
How to Tell when You Are Contagious. Four Parts: Identifying the Symptoms of a Contagious Illnesses Putting the Symptoms Together Preventing the Spread of Contagious Illnesses Watching Out for Other Contagious Illnesses Community Q&A. Being contagious means that you are capable of transmitting an illness to another person.