What is parotitis? Parotitis is the name given to inflammation and infection of the largest of the salivary glands known as the parotid glands. Inflammation results in swelling of the tissues that surround the salivary glands, redness, and soreness. Salivary glands are responsible for producing saliva in the mouth, which has the important function of cleansing the mouth. Inflammation of the salivary glands reduces their ability to function properly and may lead to infections within the mouth. The inflammation of parotitis may result from many causes, including infection, drugs, radiation, and various diseases. Mumps was once the most common viral cause of parotitis, but vaccination has made mumps a rare disease today. Parotitis caused by bacterial infection is somewhat common in the United States. Bacterial infection in parotitis results from the accumulation and growth of bacteria within the salivary glands. Among the most common causes of parotitis is obstruction of the salivary duct or poor oral hygiene. Drugs that cause dry mouth such as some antihistamines can increase the risk of parotitis, as can cancer treatments such as radiation therapy. The signs and symptoms of parotitis can vary among individuals. Some people with parotitis may not realize they have a disease, while others may have severe swelling and pain. Fortunately, parotitis can be treated successfully with medications. You can reduce your risk of developing parotitis by practicing good oral hygiene, drinking plenty of fluids, washing your hands, and receiving the MMR vaccine to prevent mumps. Seek immediate medical care (call 911) for serious symptoms such as a high fever (higher than 101 degrees Fahrenheit) and difficulty breathing or swallowing. Seek prompt medical care if you are being treated for parotitis but mild symptoms recur or are persistent.