<unk>  is a soft tissue swelling of the epiglottis, and the surrounding structures example; plica aryepiglottica , arytenoids, sinus piriformis and vestibular folds mostly caused by bacteria. The epiglottis is  a flap of tissue at the base of the tongue that prevents food from going into the trachea. Due to its place in the airway, swelling of the epiglottis may interfere with breathing and constitutes a medical emergency, especially when it obstructs or completely closes off the windpipe.
Epiglottitis
Adenoiditis
Nasal polyp
Retropharyngeal abscess
Tonsillitis
Trigonitis
Rhinosinusitis
Mastoiditis