Chronic inflammation of the<unk>  system (sialodochitis) may cause some segments of the<unk>  to narrow due to fibrosis, and others to dilate. Saliva stagnates and forms a mucus plug behind the<unk>  during sleep when the salivary output of the parotid is reduced. Then, when salivary secretion is stimulated, the mucus plug becomes stuck in the<unk> . The backlog of saliva behind the blockage causes the swelling, and the increased pressure inside the gland causes the pain. When the mucus plug is dislodged, the built up saliva is released and the swelling subsides.
Salivary duct stricture
Salivary gland atresia
Salivary gland fistula
Salivary gland hypoplasia
Ectopic salivary gland tissue
Salivary gland tumour
Salivary gland aplasia
Retropharyngeal abscess