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.
Again the question is pneumonia contagious depends on the exact germ which is the cause of infection. Many scientists are still unsure of when the period of contagion begins and finishes. Particular viruses become contagious up to three days before symptoms develop.Theoretically this means a person who has pneumonia can be contagious for approximately two weeks. But the contagion is worse when the person is suffering with serious symptoms.articular viruses become contagious up to three days before symptoms develop. Theoretically this means a person who has pneumonia can be contagious for approximately two weeks. But the contagion is worse when the person is suffering with serious symptoms.