This can occur when something obstructs a sinus passage, including:
(1) allergic rhinits
(2) sinusitis or upper respiratory tract infection
(3) a benign or malignant mass (polyp, cyst etc)
(4) fold in membrane
Signs and symptoms:
(1) sinus pain
(2) dental pain (also consider dental squeeze)
(3) nosebleeding
An inexperienced diver may panic if these symptoms occur unexpectedly.
Prevention: A person should not dive until all symptoms related to the sinuses have cleared.
Management:
(1) The pain can be relieved by descending a few feet until the pain is relieved, then slowly restarting the ascent.
(2) A decongestant may help.
(3) Antibiotic therapy may be indicated if there are signs of sinusitis.
(4) Analgesics for acute pain.