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.
Viral infections that lead to sinusitis may be contagious; bacterial sinusitis is generally not. Itâs important to remember that most viral upper respiratory infections (common colds) cause nasal congestion, which may involve the sinuses. If the viral sinus infection lasts well past the normal duration of a cold, viral sinusitis may be diagnosed. These viruses are highly contagious and likely to cause a cold in others who come in contact with them. Bacterial sinusitis most often occurs as a complication of a viral common cold. Bacteria that are normally present in the nose and throat take advantage of the viral infection to invade the inflamed sinus passages.