Brief Answer: Infection, trauma, inflammation Detailed Answer: Dear patient, Thanks for the query. "Glands", which are medically known as lymph nodes, are reactive structures that swell up in response to local trauma, a local infection, or local inflammation or a cut/bruise that alerts the immune system; the most common cause of inflammed "glands" of the head and neck are tooth problems and upper respiratory infections; these "glands" tend to return to normal size once the stimulus is over. Hope this helps, wish you the best, Dr Brenes-Salazar MD Mayo Clinic MN

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