5 Warning Signs of a Tooth Infection You Shouldn't Ignore

The hallmark of a tooth infection is pain that doesn't quit. Unlike the brief sensitivity from a cavity or the occasional twinge from a crack, infected tooth pain is constant and often described as throbbing or pulsing in rhythm with your heartbeat. This pulsing sensation occurs because the infection causes increased blood flow and pressure inside the tooth, which has no room to expand.

The pain may radiate into your jaw, ear, neck, or head. It often worsens when you lie down (blood rushes to your head, increasing pressure) and may keep you awake at night. Over-the-counter pain relievers provide limited relief.

2. Swelling in your face, jaw, or cheek

When infection spreads beyond the tooth root into surrounding tissues, visible swelling develops. You might notice puffiness along your jawline, a swollen cheek, or swelling under your chin. In some cases, one side of your face looks noticeably larger than the other.

This swelling can feel firm or tender to the touch. As the infection progresses, the swelling may spread—and spreading swelling is a serious warning sign that requires immediate attention.

3. Temperature sensitivity that lingers

While sensitivity to hot and cold is common with cavities, infected tooth sensitivity behaves differently. When you drink something cold or eat something hot, the pain doesn't stop when the stimulus is removed. It lingers for 30 seconds, a minute, or even longer.

Hot sensitivity, in particular, is a red flag for infection. A tooth that throbs in response to hot coffee or warm soup often has an inflamed or dying nerve.

4. Fever or feeling unwell

When your body is fighting an infection, it responds systemically. A tooth infection can cause fever, fatigue, body aches, and a general feeling of being unwell—similar to having the flu. These symptoms indicate that the infection has triggered a whole-body immune response.

Any fever accompanying tooth pain should be taken seriously. A high fever (over 101°F) combined with dental symptoms is a warning sign of a potentially spreading infection.

5. Bad taste in mouth or foul-smelling breath

Infections produce pus—a collection of dead bacteria, dead white blood cells, and tissue debris. When a dental abscess drains, either through the gum or into your mouth, it produces a distinctly unpleasant taste. Patients often describe it as salty, metallic, or simply foul.

You might also notice persistent bad breath that doesn't improve with brushing, or that other people mention your breath has changed. This smell comes from the bacteria and their metabolic byproducts.

Additional signs that may indicate infection:

• A pimple-like bump on your gum near the affected tooth (fistula)


• Swollen lymph nodes under your jaw or in your neck


• Sudden relief from severe pain (this may mean the abscess ruptured and drained, but the infection remains)


• Discoloration of the tooth

Difficulty breathing or swallowing
Swelling can spread to your throat and airway, compromising your ability to breathe. This is called Ludwig's angina when it affects the floor of the mouth, and it can be fatal without emergency treatment. If you feel like your throat is closing, can't swallow your saliva, or are drooling because swallowing is too difficult, call 911.

Swelling spreading to your neck or under your eye
Infection spreading downward into the neck can reach the mediastinum (the space in your chest around your heart and major vessels), while infection spreading upward can threaten your eye and even your brain. Rapid spread of swelling is a sign that the infection has broken through natural barriers and is advancing quickly.

High fever (over 101°F/38.3°C)
Significant fever indicates your body is mounting a major immune response. Combined with dental symptoms, this suggests the infection may be entering your bloodstream (sepsis) or has spread beyond the tooth.

Confusion, extreme fatigue, or altered consciousness
These can be signs of sepsis—a life-threatening condition where infection triggers a cascading inflammatory response throughout the body. Sepsis can progress rapidly and requires immediate hospital care.

Rapid heart rate
A heart rate consistently over 100 beats per minute at rest, especially with fever and dental symptoms, can indicate systemic infection.

Don't delay seeking emergency care for these symptoms. Dental infections can deteriorate rapidly, and early intervention dramatically improves outcomes.

The progression from healthy tooth to infection:
A tooth infection (dental abscess) occurs when bacteria invade the inner pulp of the tooth—the soft tissue containing nerves and blood vessels. Once inside, bacteria multiply rapidly in this warm, moist environment, producing pus and inflammation.

Common causes:

• Untreated tooth decay: This is the most common cause. As a cavity deepens, it eventually reaches the pulp chamber, allowing bacteria direct access to the nerve and blood supply.


• Cracked or fractured teeth: Any crack that extends into the pulp provides an entry point for bacteria, even if the crack is invisible to the naked eye.


• Failed previous dental work: Old fillings can develop gaps, and previous root canals can become reinfected if bacteria find their way back in.


• Gum disease: Severe periodontal disease can create pockets where bacteria can travel down alongside the tooth root, eventually reaching the tip and causing infection from the outside in.


• Trauma: A blow to the tooth can damage or kill the pulp, even without visible damage. The dead tissue then becomes a breeding ground for bacteria.

• Poor oral hygiene allowing bacteria to flourish


• High sugar diet feeding cavity-causing bacteria


• Dry mouth (saliva helps neutralize acids and control bacteria)


• Weakened immune system (diabetes, HIV, immunosuppressant medications)


• Smoking (impairs blood flow and immune function)


• Delaying dental treatment for known problems

While waiting for your appointment:

• Take over-the-counter pain relievers (ibuprofen is particularly helpful because it reduces inflammation)


• Rinse gently with warm salt water (1/2 teaspoon salt in 8 oz water)


• Avoid very hot or cold foods if they trigger pain


• Don't put aspirin directly on your gum—this is a folk remedy that can burn tissue


• Sleep with your head elevated to reduce throbbing


• Stay hydrated and eat soft foods if chewing is difficult

• Antibiotics: Often prescribed to control the infection, though antibiotics alone won't cure it—the source must be addressed


• Root canal therapy: Removes the infected pulp, cleans the canals, and seals the tooth, allowing you to keep your natural tooth


• Incision and drainage: If an abscess has formed, your dentist may need to drain it to relieve pressure and remove pus


• Extraction: If the tooth cannot be saved, removing it eliminates the source of infection