Sinusitis, also known as rhinosinusitis, is inflammation of the mucous membranes that line the sinuses resulting in symptoms that may include thick nasal mucus, a plugged nose, and facial pain. Other signs and symptoms may include fever, headaches, a poor sense of smell, sore throat, a feeling that phlegm is oozing out from the back of the nose to the throat along with a necessity to clear the throat frequently and frequent attacks of cough. Generally sinusitis starts off as a common viral infection like common cold. This infection generally subsides within 5 to 7 days. During this time the nasal structures can swell and facilitate the stagnation of fluids in sinuses that leads to acute sinusitis which lasts from 6th day of the infection to 15th day. From the 15th day to 45th day of the infection comes the subacute stage followed by chronic stage. Whenever a chronic stage patient's immunity takes a hit the infection moves to "acute on sinusitis" stage and moves back to chronic when the immunity is up. Sinusitis usually occurs in individuals with underlying conditions like allergies, or structural problems in the nose and in people with lesser immunity against bacteria by birth. Most cases are caused by a viral infection. Recurrent episodes are more likely in persons with asthma, cystic fibrosis, and poor immune function. In early stages an ENT doctor confirms sinusitis using nasal endoscopy. Diagnostic imaging is not usually needed in acute stage unless complications are suspected. In chronic cases, confirmatory testing is recommended by either direct visualization or computed tomography. Some cases may be prevented by hand washing, avoiding smoking, and immunization. Pain killers such as naproxen, nasal steroids, and nasal irrigation may be used to help with symptoms. Recommended initial treatment for acute sinusitis is watchful waiting. If symptoms do not improve in 7–10 days or get worse, then an antibiotic may be used or changed. In those in whom antibiotics are used, either amoxicillin or amoxicillin/clavulanate is recommended first line, with amoxicillin/clavulanate being superior to amoxicillin alone but with more side effects. Surgery may occasionally be used in people with chronic disease or in someone who is not responding to medicines as per doctor's expectation. Sinusitis is a common condition. It affects between about 10 and 30 percent of people each year in the United States and Europe. Chronic sinusitis affects about 12.5% of people. Treatment of sinusitis