Signs and symptoms of a tooth abscess include:

• Severe, persistent, throbbing toothache that can radiate to the jawbone, neck or ear
• Sensitivity to hot and cold temperatures
• Sensitivity to the pressure of chewing or biting
• Fever
• Swelling in your face or cheek
• Tender, swollen lymph nodes under your jaw or in your neck
• Sudden rush of foul-smelling and foul-tasting, salty fluid in your mouth and pain relief, if the abscess ruptures
• Difficulty breathing or swallowing

A periapical tooth abscess occurs when bacteria invade the dental pulp — the innermost part of the tooth that contains blood vessels, nerves and connective tissue.

Bacteria enter through either a dental cavity or a chip or crack in the tooth and spread all the way down to the root. The bacterial infection can cause swelling and inflammation at the tip of the root.

These factors may increase your risk of a tooth abscess:

• Poor dental hygiene. Not taking proper care of your teeth and gums — such as not brushing your teeth twice a day and not flossing — can increase your risk of tooth decay, gum disease, tooth abscess, and other dental and mouth complications.
• A diet high in sugar. Frequently eating and drinking foods rich in sugar, such as sweets and sodas, can contribute to dental cavities and turn into a tooth abscess.
• Dry mouth. Having a dry mouth can increase your risk of tooth decay. Dry mouth is often due to the side effect of certain medications or aging issues.

A tooth abscess won't go away without treatment. If the abscess ruptures, the pain may decrease significantly — but you still need dental treatment. If the abscess doesn't drain, the infection may spread to your jaw and to other areas of your head and neck. You might even develop sepsis — a life-threatening infection that spreads throughout your body.

If you have a weakened immune system and you leave a tooth abscess untreated, your risk of a spreading infection increases even more.